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RFC 6728 - Configuration Data Model for the IP Flow Information


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Internet Engineering Task Force (IETF)                          G. Muenz
Request for Comments: 6728                                   TU Muenchen
Category: Standards Track                                      B. Claise
ISSN: 2070-1721                                                P. Aitken
                                                     Cisco Systems, Inc.
                                                            October 2012

  Configuration Data Model for the IP Flow Information Export (IPFIX)
                 and Packet Sampling (PSAMP) Protocols

Abstract

   This document specifies a data model for the IP Flow Information
   Export (IPFIX) and Packet Sampling (PSAMP) protocols.  It is for
   configuring and monitoring Selection Processes, Caches, Exporting
   Processes, and Collecting Processes of IPFIX- and PSAMP-compliant
   Monitoring Devices using the Network Configuration Protocol
   (NETCONF).  The data model is defined using UML (Unified Modeling
   Language) class diagrams and formally specified using YANG.  The
   configuration data is encoded in Extensible Markup Language (XML).

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6728.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
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   not be created outside the IETF Standards Process, except to format
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   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  IPFIX Documents Overview  . . . . . . . . . . . . . . . .   4
     1.2.  PSAMP Documents Overview  . . . . . . . . . . . . . . . .   5
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Structure of the Configuration Data Model . . . . . . . . . .   7
     3.1.  Metering Process Decomposition in Selection Process
           and Cache . . . . . . . . . . . . . . . . . . . . . . . .   8
     3.2.  UML Representation  . . . . . . . . . . . . . . . . . . .  10
     3.3.  Exporter Configuration  . . . . . . . . . . . . . . . . .  15
     3.4.  Collector Configuration . . . . . . . . . . . . . . . . .  17
   4.  Configuration Parameters  . . . . . . . . . . . . . . . . . .  18
     4.1.  ObservationPoint Class  . . . . . . . . . . . . . . . . .  18
     4.2.  SelectionProcess Class  . . . . . . . . . . . . . . . . .  20
       4.2.1.  Selector Class  . . . . . . . . . . . . . . . . . . .  21
       4.2.2.  Sampler Classes . . . . . . . . . . . . . . . . . . .  22
       4.2.3.  Filter Classes  . . . . . . . . . . . . . . . . . . .  23
     4.3.  Cache Class . . . . . . . . . . . . . . . . . . . . . . .  25
       4.3.1.  ImmediateCache Class  . . . . . . . . . . . . . . . .  26
       4.3.2.  TimeoutCache, NaturalCache, and PermanentCache
               Class . . . . . . . . . . . . . . . . . . . . . . . .  27
       4.3.3.  CacheLayout Class . . . . . . . . . . . . . . . . . .  29
     4.4.  ExportingProcess Class  . . . . . . . . . . . . . . . . .  32
       4.4.1.  SctpExporter Class  . . . . . . . . . . . . . . . . .  34
       4.4.2.  UdpExporter Class . . . . . . . . . . . . . . . . . .  36
       4.4.3.  TcpExporter Class . . . . . . . . . . . . . . . . . .  37
       4.4.4.  FileWriter Class  . . . . . . . . . . . . . . . . . .  38
       4.4.5.  Options Class . . . . . . . . . . . . . . . . . . . .  39
     4.5.  CollectingProcess Class . . . . . . . . . . . . . . . . .  41
       4.5.1.  SctpCollector Class . . . . . . . . . . . . . . . . .  42
       4.5.2.  UdpCollector Class  . . . . . . . . . . . . . . . . .  43

       4.5.3.  TcpCollector Class  . . . . . . . . . . . . . . . . .  44
       4.5.4.  FileReader Class  . . . . . . . . . . . . . . . . . .  45
     4.6.  Transport Layer Security Class  . . . . . . . . . . . . .  46
     4.7.  Transport Session Class . . . . . . . . . . . . . . . . .  49
     4.8.  Template Class  . . . . . . . . . . . . . . . . . . . . .  53
   5.  Adaptation to Device Capabilities . . . . . . . . . . . . . .  54
   6.  YANG Module of the IPFIX/PSAMP Configuration Data Model . . .  57
   7.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . . 104
     7.1.  PSAMP Device  . . . . . . . . . . . . . . . . . . . . . . 104
     7.2.  IPFIX Device  . . . . . . . . . . . . . . . . . . . . . . 115
     7.3.  Export of Flow Records and Packet Reports . . . . . . . . 118
     7.4.  Collector and File Writer . . . . . . . . . . . . . . . . 121
     7.5.  Deviations  . . . . . . . . . . . . . . . . . . . . . . . 122
   8.  Security Considerations . . . . . . . . . . . . . . . . . . . 122
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . 124
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 125
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . . 125
     11.1. Normative References  . . . . . . . . . . . . . . . . . . 125
     11.2. Informative References  . . . . . . . . . . . . . . . . . 126

1.  Introduction

   IPFIX- and PSAMP-compliant Monitoring Devices (routers, switches,
   monitoring probes, Collectors, etc.) offer various configuration
   possibilities that allow adapting network monitoring to the goals and
   purposes of the application, such as accounting and charging, traffic
   analysis, performance monitoring, and security monitoring.  The use
   of a common vendor-independent configuration data model for IPFIX-
   and PSAMP-compliant Monitoring Devices facilitates network management
   and configuration, especially if Monitoring Devices of different
   implementers or manufacturers are deployed simultaneously.  On the
   one hand, a vendor-independent configuration data model helps to
   store and manage the configuration data of Monitoring Devices in a
   consistent format.  On the other hand, it can be used for local and
   remote configuration of Monitoring Devices.

   The purpose of this document is the specification of a vendor-
   independent configuration data model that covers the commonly
   available configuration parameters of Selection Processes, Caches,
   Exporting Processes, and Collecting Processes.  In addition, it
   includes common states parameters of a Monitoring Device.  The
   configuration data model is defined using UML (Unified Modeling
   Language) class diagrams [UML], while the actual configuration data
   is encoded in Extensible Markup Language (XML)
   [W3C.REC-xml-20081126].  An XML document conforming to the
   configuration data model contains the configuration data of one
   Monitoring Device.

   The configuration data model is designed for use with the NETCONF
   protocol [RFC6241] in order to configure remote Monitoring Devices.
   With the NETCONF protocol, it is possible to transfer a complete set
   of configuration data to a Monitoring Device, to query the current
   configuration and state parameters of a Monitoring Device, and to
   change specific parameter values of an existing Monitoring Device
   configuration.

   In order to ensure compatibility with the NETCONF protocol [RFC6241],
   YANG [RFC6020] is used to formally specify the configuration data
   model.  If required, the YANG specification of the configuration data
   model can be converted into XML Schema language
   [W3C.REC-xmlschema-0-20041028] or DSDL (Document Schema Definition
   Languages) [RFC6110], for example, by using the pyang tool
   [YANG-WEB].  YANG provides mechanisms to adapt the configuration data
   model to device-specific constraints and to augment the model with
   additional device-specific or vendor-specific parameters.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

1.1.  IPFIX Documents Overview

   The IPFIX protocol [RFC5101] provides network administrators with
   access to IP Flow information.  The architecture for the export of
   measured IP Flow information out of an IPFIX Exporting Process to a
   Collecting Process is defined in [RFC5470], per the requirements
   defined in [RFC3917].  The IPFIX protocol [RFC5101] specifies how
   IPFIX Data Records and Templates are carried via a number of
   transport protocols from IPFIX Exporting Processes to IPFIX
   Collecting Process.  IPFIX has a formal description of IPFIX
   Information Elements, their name, type, and additional semantic
   information, as specified in [RFC5102].  [RFC6615] specifies the
   IPFIX Management Information Base, consisting of the IPFIX MIB module
   and the IPFIX SELECTOR MIB module.  Finally, [RFC5472] describes what
   type of applications can use the IPFIX protocol and how they can use
   the information provided.  It furthermore shows how the IPFIX
   framework relates to other architectures and frameworks.  Methods for
   efficient export of bidirectional Flow information and common
   properties in Data Records are specified in [RFC5103] and [RFC5473],
   respectively.  [RFC5610] addresses the export of extended type
   information for enterprise-specific Information Elements.  The
   storage of IPFIX Messages in a file is specified in [RFC5655].

1.2.  PSAMP Documents Overview

   The framework for packet selection and reporting [RFC5474] enables
   network elements to select subsets of packets by statistical and
   other methods, and to export a stream of reports on the selected
   packets to a Collector.  The set of packet selection techniques
   (Sampling, Filtering, and hashing) standardized by PSAMP is described
   in [RFC5475].  The PSAMP protocol [RFC5476] specifies the export of
   packet information from a PSAMP Exporting Process to a PSAMP
   Collector.  Instead of exporting PSAMP Packet Reports, the stream of
   selected packets may also serve as input to the generation of IPFIX
   Flow Records.  Like IPFIX, PSAMP has a formal description of its
   Information Elements, their name, type, and additional semantic
   information.  The PSAMP information model is defined in [RFC5477].
   [RFC6727] specifies the PSAMP MIB module as an extension of the IPFIX
   SELECTOR MIB module defined in [RFC6615].

2.  Terminology

   This document adopts the terminologies used in [RFC5101], [RFC5103],
   [RFC5655], and [RFC5476].  As in these documents, all specific terms
   have the first letter of a word capitalized when used in this
   document.  The following listing indicates in which references the
   definitions of those terms that are commonly used throughout this
   document can be found:

   o  Definitions adopted from [RFC5101]:
      *  Collection Process
      *  Collector
      *  Data Record
      *  Exporter
      *  Flow
      *  Flow Key
      *  Flow Record
      *  Information Element
      *  IPFIX Device
      *  IPFIX Message
      *  Observation Domain
      *  Observation Point
      *  (Options) Template

   o  Definitions adopted from [RFC5103]:
      *  Reverse Information Element

   o  Definitions adopted from [RFC5655]:
      *  File Reader
      *  File Writer

   o  Definitions adopted from [RFC5476]:
      *  Filtering
      *  Observed Packet Stream
      *  Packet Report
      *  PSAMP Device
      *  Sampling
      *  Selection Process
      *  Selection Sequence
      *  Selection Sequence Report Interpretation
      *  Selection Sequence Statistics Report Interpretation
      *  Selection State
      *  Selector, Primitive Selector, Composite Selector
      *  Selector Report Interpretation

   The terms Metering Process and Exporting Process have different
   definitions in [RFC5101] and [RFC5476].  In the scope of this
   document, these terms are used according to the following
   definitions, which cover the deployment in both PSAMP Devices and
   IPFIX Devices:

   Metering Process

      The Metering Process generates IPFIX Flow Records or PSAMP Packet
      Reports, depending on its deployment as part of an IPFIX Device or
      PSAMP Device.  Inputs to the process are packets observed at one
      or more Observation Points, as well as characteristics describing
      the packet treatment at these Observation Points.  If IPFIX Flow
      Records are generated, the Metering Process MUST NOT aggregate
      packets observed at different Observation Domains in the same
      Flow.  The function of the Metering Process is split into two
      functional blocks: Selection Process and Cache.

   Exporting Process

      Depending on its deployment as part of an IPFIX Device or PSAMP
      Device, the Exporting Process sends IPFIX Flow Records or PSAMP
      Packet Reports to one or more Collecting Processes.  The IPFIX
      Flow Records or PSAMP Packet Reports are generated by one or more
      Metering Processes.

   In addition to the existing IPFIX and PSAMP terminology, the
   following terms are defined:

   Cache

      The Cache is a functional block in a Metering Process that
      generates IPFIX Flow Records or PSAMP Packet Reports from a
      Selected Packet Stream, in accordance with its configuration.  If

      Flow Records are generated, the Cache performs tasks like creating
      new records, updating existing ones, computing Flow statistics,
      deriving further Flow properties, detecting Flow expiration,
      passing Flow Records to the Exporting Process, and deleting Flow
      Records.  If Packet Reports are generated, the Cache performs
      tasks like extracting packet contents and derived packet
      properties from the Selected Packet Stream, creating new records,
      and passing them as Packet Reports to the Exporting Process.

   Cache Layout

      The Cache Layout defines the superset of fields that are included
      in the Packet Reports or Flow Records maintained by the Cache.
      The fields are specified by the corresponding Information
      Elements.  In general, the largest possible subset of the
      specified fields is derived for every Packet Report or Flow
      Record.  More specific rules about which fields must be included
      are given in Section 4.3.3.

   Monitoring Device

      A Monitoring Device implements at least one of the functional
      blocks specified in the context of IPFIX or PSAMP.  In particular,
      the term Monitoring Device encompasses Exporters, Collectors,
      IPFIX Devices, and PSAMP Devices.

   Selected Packet Stream

      The Selected Packet Stream is the set of all packets selected by a
      Selection Process.

3.  Structure of the Configuration Data Model

   The IPFIX reference model in [RFC5470] describes Metering Processes,
   Exporting Processes, and Collecting Processes as functional blocks of
   IPFIX Devices.  The PSAMP framework [RFC5474] provides the
   corresponding information for PSAMP Devices and introduces the
   Selection Process as a functional block within Metering Processes.
   In Section 2 of the document, the Cache is defined as another
   functional block within Metering Processes.  Further explanations
   about the relationship between Selection Process and Cache are given
   in Section 3.1.  IPFIX File Reader and File Writer are defined as
   specific kinds of Exporting and Collecting Processes in [RFC5655].

   Monitoring Device implementations usually maintain the separation of
   various functional blocks, although they do not necessarily implement
   all of them.  Furthermore, they provide various configuration
   possibilities; some of them are specified as mandatory by the IPFIX

   protocol [RFC5101] or PSAMP protocol [RFC5476].  The configuration
   data model enables the setting of commonly available configuration
   parameters for Selection Processes, Caches, Exporting Processes, and
   Collecting Processes.  In addition, it allows specifying the
   composition of functional blocks within a Monitoring Device
   configuration and their linkage with Observation Points.

   The selection of parameters in the configuration data model is based
   on configuration issues discussed in the IPFIX and PSAMP documents
   [RFC3917], [RFC5101], [RFC5470], [RFC5476], [RFC5474], and [RFC5475].
   Furthermore, the structure and content of the IPFIX MIB module
   [RFC6615] and the PSAMP MIB module [RFC6727] have been taken into
   consideration.  Consistency between the configuration data model and
   the IPFIX and PSAMP MIB modules is an intended goal.  Therefore,
   parameters in the configuration data model are named according to
   corresponding managed objects.  Certain IPFIX MIB objects containing
   state data have been adopted as state parameters in the configuration
   data model.  State parameters cannot be configured, yet their values
   can be queried from the Monitoring Device by a network manager.

   Section 3.2 explains how UML class diagrams are deployed to
   illustrate the structure of the configuration data model.
   Thereafter, Section 3.3 and Section 3.4 explain the class diagrams
   for the configuration of Exporters and Collectors, respectively.
   Each of the presented classes contains specific configuration
   parameters that are specified in Section 4.  Section 5 gives a short
   introduction to YANG concepts that allow adapting the configuration
   data model to the capabilities of a device.  The formal definition of
   the configuration data model in YANG is given in Section 6.
   Section 7 illustrates the usage of the model with example
   configurations in XML.

3.1.  Metering Process Decomposition in Selection Process and Cache

   In a Monitoring Device implementation, the functionality of the
   Metering Process is commonly split into packet Sampling and Filtering
   functions performed by Selection Processes, and the maintenance of
   Flow Records and Packet Reports is performed by a Cache.  Figure 1
   illustrates this separation with the example of a basic Metering
   Process.

               +-----------------------------------+
               | Metering Process                  |
               | +-----------+ Selected            |
      Observed | | Selection | Packet    +-------+ |  Stream of
      Packet  -->| Process   |---------->| Cache |--> Flow Records or
      Stream   | +-----------+ Stream    +-------+ |  Packet Reports
               +-----------------------------------+

     Figure 1: Selection Process and Cache forming a Metering Process

   The configuration data model adopts the separation of Selection
   Processes and Caches in order to support the flexible configuration
   and combination of these functional blocks.  As defined in [RFC5476],
   the Selection Process takes an Observed Packet Stream as its input
   and selects a subset of that stream as its output (Selected Packet
   Stream).  The action of the Selection Process on a single packet of
   its input is defined by one Selector (called a Primitive Selector) or
   an ordered composition of multiple Selectors (called a Composite
   Selector).  The Cache generates Flow Records or Packet Reports from
   the Selected Packet Stream, depending on its configuration.

   The configuration data model does not allow configuring a Metering
   Process without any Selection Process in front of the Cache.  If all
   packets in the Observed Packet Stream shall be selected and passed to
   the Cache without any Filtering or Sampling, a Selection Process
   needs to be configured with a Selector that selects all packets
   ("SelectAll" class in Section 4.2.1).

   The configuration data model enables the configuration of a Selection
   Process that receives packets from multiple Observation Points as its
   input.  In this case, the Observed Packet Streams of the Observation
   Points are processed in independent Selection Sequences.  As
   specified in [RFC5476], a distinct set of Selector instances needs to
   be maintained per Selection Sequence in order to keep the Selection
   States and statistics separate.

   With the configuration data model, it is possible to configure a
   Metering Process with more than one Selection Processes whose output
   is processed by a single Cache.  This is illustrated in Figure 2.

              +-------------------------------------+
              | Metering Process                    |
              | +-----------+ Selected              |
     Observed | | Selection | Packet                |
     Packet  -->| Process   |----------+  +-------+ |
     Stream   | +-----------+ Stream   +->|       | |  Stream of
              |      ...                  | Cache |--> Flow Records or
              | +-----------+ Selected +->|       | |  Packet Reports
     Observed | | Selection | Packet   |  +-------+ |
     Packet  -->| Process   |----------+            |
     Stream   | +-----------+ Stream                |
              +-------------------------------------+

       Figure 2: Metering Process with multiple Selection Processes

   The Observed Packet Streams at the input of a Metering Process may
   originate from Observation Points belonging to different Observation
   Domains.  By definition of the Observation Domain (see [RFC5101]),
   however, a Cache MUST NOT aggregate packets observed at different
   Observation Domains in the same Flow.  Hence, if the Cache is
   configured to generate Flow Records, it needs to distinguish packets
   according to their Observation Domains.

3.2.  UML Representation

   We use UML class diagrams [UML] to explain the structure of the
   configuration data model.  The attributes of the classes are the
   configuration or state parameters.  The configuration and state
   parameters of a given Monitoring Device are represented as objects of
   these classes encoded in XML.

    +------------------------------+
    | SctpExporter                 |
    +------------------------------+    0..1 +------------------------+
    | name                         |<>-------| TransportLayerSecurity |
    | ipfixVersion = 10            |         +------------------------+
    | sourceIPAddress[0..*]        |
    | destinationIPAddress[1..*]   |    0..1 +------------------------+
    | destinationPort = 4739|4740  |<>-------| TransportSession       |
    | ifName/ifIndex[0..1]         |         +------------------------+
    | sendBufferSize {opt.}        |
    | rateLimit[0..1]              |
    | timedReliability = 0         |
    +------------------------------+

                 Figure 3: UML example: SctpExporter class

   As an example, Figure 3 shows the UML diagram of the SctpExporter
   class, which is specified in more detail in Section 4.4.1.  The upper
   box contains the name of the class.  The lower box lists the
   attributes of the class.  Each attribute corresponds to a parameter
   of the configuration data model.

   Behind an attribute's name, there may appear a multiplicity indicator
   in brackets (i.e., between "[" and "]").  An attribute with
   multiplicity indicator "[0..1]" represents an OPTIONAL configuration
   parameter that is only included in the configuration data if the user
   configures it.  Typically, the absence of an OPTIONAL parameter has a
   specific meaning.  For example, not configuring rateLimit in an
   object of the SctpExporter class means that no rate limiting will be
   applied to the exported data.  In YANG, an OPTIONAL parameter is
   specified as a "leaf" without "mandatory true" substatement.  The
   "description" substatement specifies the behavior for the case that
   the parameter is not configured.

   The multiplicity indicator "[0..*]" means that this parameter is
   OPTIONAL and MAY be configured multiple times with different values.
   In the example, multiple source IP addresses (sourceIPAddress) may be
   configured for a multihomed Exporting Process.  In YANG, an attribute
   with multiplicity indicator "[0..*]" corresponds to a "leaf-list".

   The multiplicity indicator "[1..*]" means that this parameter MUST be
   configured at least once and MAY be configured multiple times with
   different values.  In the example, one or more destination IP
   addresses (destinationIPAddress) must be configured to specify the
   export destination.  In YANG, an attribute with multiplicity
   indicator "[1..*]" corresponds to a "leaf-list" with "min-elements 1"
   substatement.  Note that attributes without this multiplicity
   indicator MUST NOT appear more than once in each object of the class.

   Attributes without multiplicity indicator may be endued with a
   default value that is indicated behind the equality symbol ("=").  If
   a default value exists, the parameter does not have to be explicitly
   configured by the user.  If the parameter is not configured by the
   user, the Monitoring Device MUST use the specified default value for
   the given parameter.  In the example, IPFIX version 10 must be used
   unless a different value is configured for ipfixVersion.  In YANG, an
   attribute with default value corresponds to a "leaf" with "default"
   substatement.

   In the example, there exist two default values for the destination
   port (destinationPort) -- namely, the registered ports for IPFIX with
   and without transport layer security (i.e., DTLS or TLS), which are
   4740 and 4739, respectively.  In the UML diagram, the two default
   values are separated by a vertical bar ("|").  In YANG, such

   conditional default value alternatives cannot be specified formally.
   Instead, they are defined in the "description" substatement of the
   "leaf".

   Further attribute properties are denoted in braces (i.e., between "{"
   and "}").  An attribute with property "{opt.}", such as
   sendBufferSize in the SctpExporter class, represents a parameter that
   MAY be configured by the user.  If not configured by the user, the
   Monitoring Device MUST set an appropriate value for this parameter at
   configuration time.  As a result, the parameter will always exist in
   the configuration data, yet it is not mandatory for the user to
   configure it.  This behavior can be implemented as a static device-
   specific default value, but does not have to be.  Therefore, the user
   MUST NOT expect that the device always sets the same values for the
   same parameter.  Regardless of whether the parameter value has been
   configured by the user or set by the device, the parameter value MUST
   NOT be changed by the device after configuration.  Since this
   behavior cannot be specified formally in YANG, it is specified in the
   "description" substatement of the "leaf".

   The availability of a parameter may depend on another parameter
   value.  In the UML diagram, such restrictions are indicated as
   attribute properties (e.g., "{SCTP only}").  The given example does
   not show such restrictions.  In YANG, the availability of a parameter
   is formally restricted with the "when" substatement of the "leaf".

   Another attribute property not shown in the example is "{readOnly}",
   which specifies state parameters that cannot be configured.  In YANG,
   this corresponds to the "config false" substatement.

   Attributes without multiplicity indicator, without default value, and
   without "{readOnly}" property are mandatory configuration parameters.
   These parameters MUST be configured by the user unless an attribute
   property determines that the parameter is not available.  In YANG, a
   mandatory parameter corresponds to a "leaf" with "mandatory true"
   substatement.  In the example, the user MUST configure the name
   parameter.

   If some parameters are related to each other, it makes sense to group
   these parameters in a subclass.  This is especially useful if
   different subclasses represent choices of different parameter sets,
   or if the parameters of a subclass may appear multiple times.  For
   example, the SctpExporter class MAY contain the parameters of the
   TransportLayerSecurity subclass.

   An object of a class is encoded as an XML element.  In order to
   distinguish between classes and objects, class names start with an
   uppercase character while the associated XML elements start with

   lowercase characters.  Parameters appear as XML elements that are
   nested in the XML element of the object.  In XML, the parameters of
   an object can appear in any order and do not have to follow the order
   in the UML class diagram.  Unless specified differently, the order in
   which parameters appear does not have a meaning.  As an example, an
   object of the SctpExporter class corresponds to one occurrence of

     <sctpExporter>
       <name>my-sctp-export</name>
       ...
     </sctpExporter>

   There are various possibilities how objects of classes can be related
   to each other.  In the scope of this document, we use two different
   types of relationship between objects: aggregation and unidirectional
   association.  In UML class diagrams, two different arrow types are
   used as shown in Figure 4.

            +---+   0..* +---+         +---+ 0..*  1 +---+
            | A |<>------| B |         | A |-------->| B |
            +---+        +---+         +---+         +---+
             (a) Aggregation     (b) Unidirectional association

            Figure 4: Class relationships in UML class diagrams

   Aggregation means that one object is part of the other object.  In
   Figure 4 (a), an object of class B is part of an object of class A.
   This corresponds to nested XML elements:

     <a>
       <b>
         ...
       </b>
       ...
     </a>

   In the example, objects of the TransportLayerSecurity class and the
   TransportSession class appear as nested XML elements
   <transportLayerSecurity> and <transportSession> within an object of
   the SctpExporter class <sctpExporter>.

   A unidirectional association is a reference to an object.  In
   Figure 4(b), an object of class A contains a reference to an object
   of class B.  This corresponds to separate XML elements that are not
   nested.  To distinguish different objects of class B, class B must
   have a key.  In the configuration data model, keys are string
   parameters called "name", corresponding to XML elements <name>.  The
   names MUST be unique within the given XML subtree.  The reference to

   a specific object of class B is encoded with an XML element <b>,
   which contains the name of an object.  If an object of class A refers
   to the object of class B with name "foo", this looks as follows:

     <a>
       ...
       <b>foo</b>
       ...
     </a>

     <b>
       <name>foo</name>
       ...
     </b>

   In Figure 4, the indicated numbers define the multiplicity:

      "1": one only
      "0..*": zero or more
      "1..*": one or more

   In the case of aggregation, the multiplicity indicates how many
   objects of one class may be included in one object of the other
   class.  In Figure 4(a), an object of class A may contain an arbitrary
   number of objects of class B.  In the case of unidirectional
   association, the multiplicity at the arrowhead specifies the number
   of objects of a given class that may be referred to.  The
   multiplicity at the arrow tail specifies how many different objects
   of one class may refer to a single object of the other class.  In
   Figure 4(b), an object of class A refers to single object of class B.
    One object of class B can be referred to from an arbitrary number of
   objects of class A.

   Similar to classes that are referenced in UML associations, classes
   that contain configuration parameters and that occur in an
   aggregation relationship with multiplicity greater than one must have
   a key.  This key is necessary because every configuration parameter
   must be addressable in order to manipulate or delete it.  The key
   values MUST be unique in the given XML subtree (i.e., unique within
   the aggregating object).  Hence, if class B in Figure 4(a) contains a
   configuration parameter, all objects of class B belonging to the same
   object of class A must have different key values.  Again, the key
   appears as an attribute called "name" in the concerned classes.

   A class that contains state parameters but no configuration
   parameters, such as the Template class (see Section 4.8), does not
   have a key.  This is because state parameters cannot be manipulated
   or deleted, and therefore do not need to be addressable.

   Note that the usage of keys as described above is required by YANG
   [RFC6020], which mandates the existence of a key for elements that
   appear in a list of configuration data.

   The configuration data model for IPFIX and PSAMP makes use of
   unidirectional associations to specify the data flow between
   different functional blocks.  For example, if the output of a
   Selection Process is processed by a Cache, this corresponds to an
   object of the SelectionProcess class that contains a reference to an
   object of the Cache class.  The configuration data model does not
   mandate that such a reference exists for every functional block that
   has an output.  If such a reference is absent, the output is dropped
   without any further processing.  Although such configurations are
   incomplete, we do not consider them invalid as they may temporarily
   occur if a Monitoring Device is configured in multiple steps.  Also,
   it might be useful to pre-configure certain functions of a Monitoring
   Device in order to be able to switch to a new configuration more
   quickly.

3.3.  Exporter Configuration

   Figure 5 below shows the main classes of the configuration data model
   that are involved in the configuration of an IPFIX or PSAMP Exporter.
   The role of the classes can be briefly summarized as follows:

   o  The ObservationPoint class specifies an Observation Point (i.e.,
      an interface or linecard) of the Monitoring Device at which
      packets are captured for traffic measurements.  An object of the
      ObservationPoint class may be associated with one or more objects
      of the SelectionProcess class configuring Selection Processes that
      process the observed packets in parallel.  As long as an
      ObservationPoint object is specified without any references to
      SelectionProcess objects, the captured packets are not considered
      by any Metering Process.

   o  The SelectionProcess class contains the configuration and state
      parameters of a Selection Process.  The Selection Process may be
      composed of a single Selector or a sequence of Selectors, defining
      a Primitive or Composite Selector, respectively.

      The Selection Process selects packets from one or more Observed
      Packet Streams, each originating from a different Observation
      Point.  Therefore, a SelectionProcess object MAY be referred to
      from one or more ObservationPoint objects.

      A Selection Process MAY pass the Selected Packet Stream to a
      Cache.  Therefore, the SelectionProcess class contains a reference
      to an object of the Cache class.  If a Selection Process is
      configured without any reference to a Cache, the selected packets
      are not accounted in any Packet Report or Flow Record.

   o  The Cache class contains configuration and state parameters of a
      Cache.  A Cache may receive the output of one or more Selection
      Processes and maintains corresponding Packet Reports or Flow
      Records.  Therefore, an object of the Cache class MAY be referred
      to from multiple SelectionProcess objects.

      Configuration parameters of the Cache class specify the size of
      the Cache, the Cache Layout, and expiration parameters if
      applicable.  The Cache configuration also determines whether
      Packet Reports or Flow Records are generated.

      A Cache MAY pass its output to one or more Exporting Processes.
      Therefore, the Cache class enables references to one or more
      objects of the ExportingProcess class.  If a Cache object does not
      specify any reference to an ExportingProcess object, the Cache
      output is dropped.

   o  The ExportingProcess class contains configuration and state
      parameters of an Exporting Process.  It includes various
      transport-protocol-specific parameters and the export
      destinations.  An object of the ExportingProcess class MAY be
      referred to from multiple objects of the Cache class.

      An Exporting Process MAY be configured as a File Writer according
      to [RFC5655].

                            +------------------+
                            | ObservationPoint |
                            +------------------+
                                 0..* |
                                      |
                                 0..* V
                            +------------------+
                            | SelectionProcess |
                            +------------------+
                                 0..* |
                                      |
                                 0..1 V
                            +------------------+
                            | Cache            |
                            +------------------+
                                 0..* |
                                      |
                                 0..* V
                            +------------------+
                            | ExportingProcess |
                            +------------------+

             Figure 5: Class diagram of Exporter configuration

3.4.  Collector Configuration

   Figure 6 below shows the main classes of the configuration data model
   that are involved in the configuration of a Collector.  An object of
   the CollectingProcess class specifies the local IP addresses,
   transport protocols, and port numbers of a Collecting Process.
   Alternatively, the Collecting Process MAY be configured as a File
   Reader according to [RFC5655].

   An object of the CollectingProcess class may refer to one or more
   ExportingProcess objects configuring Exporting Processes that
   reexport the received data.  As an example, an Exporting Process can
   be configured as a File Writer in order to save the received IPFIX
   Messages in a file.

                           +-------------------+
                           | CollectingProcess |
                           +-------------------+
                                0..* |
                                     |
                                0..* V
                           +-------------------+
                           | ExportingProcess  |
                           +-------------------+

            Figure 6: Class diagram of Collector configuration

4.  Configuration Parameters

   This section specifies the configuration and state parameters of the
   configuration data model separately for each class.

4.1.  ObservationPoint Class

         +-------------------------------+
         | ObservationPoint              |
         +-------------------------------+
         | name                          |
         | observationPointId {readOnly} |
         | observationDomainId           | 0..*
         | ifName[0..*]                  |-------------+
         | ifIndex[0..*]                 |             | 0..*
         | entPhysicalName[0..*]         |             V
         | entPhysicalIndex[0..*]        |    +------------------+
         | direction = "both"            |    | SelectionProcess |
         +-------------------------------+    +------------------+

                     Figure 7: ObservationPoint class

   Figure 7 shows the ObservationPoint class that specifies an
   Observation Point of the Monitoring Device.

   As defined in [RFC5101], an Observation Point can be any location
   where packets are observed.  A Monitoring Device potentially has more
   than one such location.  An instance of ObservationPoint class
   defines which location is associated with a specific Observation
   Point.  For this purpose, interfaces and physical entities are
   identified using their names.  Alternatively, index values of the
   corresponding entries in the ifTable (IF-MIB module [RFC2863]) or the
   entPhysicalTable (ENTITY-MIB module [RFC4133]) can be used as
   identifiers.  However, indices SHOULD only be used as identifiers if
   an SNMP agent on the same Monitoring Device enables access to the
   corresponding MIB tables.

   By its definition in [RFC5101], an Observation Point may be
   associated with a set of interfaces.  Therefore, the configuration
   data model allows configuring multiple interfaces and physical
   entities for a single Observation Point.

   The Observation Point ID (i.e., the value of the Information Element
   observationPointId [IANA-IPFIX]) is assigned by the Monitoring
   Device.  It appears as a state parameter in the ObservationPoint
   class.

   The configuration parameters of the Observation Point are:

   observationDomainId:  This parameter defines the identifier of the
      Observation Domain the Observation Point belongs to.  Observation
      Points that are configured with the same Observation Domain ID
      belong to the same Observation Domain.
      Note that this parameter corresponds to
      ipfixObservationPointObservationDomainId in the IPFIX MIB module
      [RFC6615].

   ifName/ifIndex/entPhysicalName/entPhysicalIndex:  These parameters
      identify interfaces and physical entities (e.g., linecards) that
      are on the Monitoring Device and are associated with the given
      Observation Point.
      An interface is either identified by its name (ifName) or the
      ifIndex value of the corresponding object in the IF-MIB module
      [RFC2863]. ifIndex SHOULD only be used if an SNMP agent enables
      access to the ifTable.
      Similarly, a physical entity is either identified by its name
      (entPhysicalName) or the entPhysicalIndex value of the
      corresponding object in the ENTITY-MIB module [RFC4133].
      entPhysicalIndex SHOULD only be used if an SNMP agent enables
      access to the entPhysicalTable.
      Note that the parameters ifIndex and entPhysicalIndex correspond
      to ipfixObservationPointPhysicalInterface and
      ipfixObservationPointPhysicalEntity in the IPFIX MIB module
      [RFC6615].

   direction:  This parameter specifies if ingress traffic, egress
      traffic, or both ingress and egress traffic is captured, using the
      values "ingress", "egress", and "both", respectively.  If not
      configured, ingress and egress traffic is captured (i.e., the
      default value is "both").  If not applicable (e.g., in the case of
      a sniffing interface in promiscuous mode), the value of this
      parameter is ignored.

   An ObservationPoint object MAY refer to one or more SelectionProcess
   objects configuring Selection Processes that process the observed
   packets in parallel.

4.2.  SelectionProcess Class

       +------------------+
       | SelectionProcess |
       +------------------+   1..* +----------+
       | name             |<>------| Selector |
       |                  |        +----------+
       |                  |
       |                  |   0..* +--------------------------------+
       |                  |<>------| SelectionSequence              |
       |                  |        +--------------------------------+
       |                  |        | observationDomainId {readOnly} |
       |                  |        | selectionSequenceId {readOnly} |
       |                  |        +--------------------------------+
       |                  |
       |                  | 0..*  0..1 +-------+
       |                  |----------->| Cache |
       +------------------+            +-------+

                     Figure 8: SelectionProcess class

   Figure 8 shows the SelectionProcess class.  The SelectionProcess
   class contains the configuration and state parameters of a Selection
   Process that selects packets from one or more Observed Packet Streams
   and generates a Selected Packet Stream as its output.  A non-empty
   ordered list defines a sequence of Selectors.  The actions defined by
   the Selectors are applied to the stream of incoming packets in the
   specified order.

   If the Selection Process receives packets from multiple Observation
   Points, the Observed Packet Streams need to be processed
   independently in separate Selection Sequences.  Each Selection
   Sequence is identified by a Selection Sequence ID that is unique
   within the Observation Domain the Observation Point belongs to (see
   [RFC5477]).  Selection Sequence IDs are assigned by the Monitoring
   Device.  As state parameters, the SelectionProcess class contains a
   list of (observationDomainId, selectionSequenceId) tuples specifying
   the assigned Selection Sequence IDs and corresponding Observation
   Domain IDs.  With this information, it is possible to associate
   Selection Sequence (Statistics) Report Interpretations exported
   according to the PSAMP protocol specification [RFC5476] with the
   corresponding object of the SelectionProcess class.

   A SelectionProcess object MAY include a reference to an object of the
   Cache class to generate Packet Reports or Flow Records from the
   Selected Packet Stream.

4.2.1.  Selector Class

    +--------------------------------------+
    | Selector                             |
    +--------------------------------------+      1 +-----------------+
    | name                                 |<>------+ SelectAll/      |
    | packetsObserved {readOnly}           |        | SampCountBased/ |
    | packetsDropped {readOnly}            |        | SampTimeBased/  |
    | selectorDiscontinuityTime {readOnly} |        | SampRandOutOfN/ |
    |                                      |        | SampUniProb/    |
    |                                      |        | FilterMatch/    |
    |                                      |        | FilterHash/     |
    +--------------------------------------+        +-----------------+

                         Figure 9: Selector class

   The Selector class in Figure 9 contains the configuration and state
   parameters of a Selector.  Standardized PSAMP Sampling and Filtering
   methods are described in [RFC5475]; their configuration parameters
   are specified in the classes SampCountBased, SampTimeBased,
   SampRandOutOfN, SampUniProb, FilterMatch, and FilterHash.  In
   addition, the SelectAll class, which has no parameters, is used for a
   Selector that selects all packets.  The Selector class includes
   exactly one of these sampler and filter classes, depending on the
   applied method.

   As state parameters, the Selector class contains the Selector
   statistics packetsObserved and packetsDropped as well as
   selectorDiscontinuityTime, which correspond to the IPFIX MIB module
   objects ipfixSelectionProcessStatsPacketsObserved,
   ipfixSelectionProcessStatsPacketsDropped, and
   ipfixSelectionProcessStatsDiscontinuityTime, respectively [RFC6615]:

   packetsObserved:  The total number of packets observed at the input
      of the Selector.  If this is the first Selector in the Selection
      Process, this counter corresponds to the total number of packets
      in all Observed Packet Streams at the input of the Selection
      Process.  Otherwise, the counter corresponds to the total number
      of packets at the output of the preceding Selector.
      Discontinuities in the value of this counter can occur at
      re-initialization of the management system, and at other times as
      indicated by the value of selectorDiscontinuityTime.

   packetsDropped:  The total number of packets discarded by the
      Selector.  Discontinuities in the value of this counter can occur
      at re-initialization of the management system, and at other times
      as indicated by the value of selectorDiscontinuityTime.

   selectorDiscontinuityTime:  Timestamp of the most recent occasion at
      which one or more of the Selector counters suffered a
      discontinuity.  In contrast to
      ipfixSelectionProcessStatsDiscontinuityTime, the time is absolute
      and not relative to sysUpTime.

   Note that packetsObserved and packetsDropped are aggregate statistics
   calculated over all Selection Sequences of the Selection Process.
   This is in contrast to the counter values in the Selection Sequence
   Statistics Report Interpretation [RFC5476], which are related to a
   single Selection Sequence only.

4.2.2.  Sampler Classes

        +----------------+   +----------------+   +----------------+
        | SampCountBased |   | SampTimeBased  |   | SampRandOutOfN |
        +----------------+   +----------------+   +----------------+
        | packetInterval |   | timeInterval   |   | population     |
        | packetSpace    |   | timeSpace      |   | size           |
        +----------------+   +----------------+   +----------------+

        +----------------+
        | SampUniProb    |
        +----------------+
        | probability    |
        +----------------+

                        Figure 10: Sampler classes

   The Sampler classes in Figure 10 contain the configuration parameters
   of specific Sampling algorithms:

   packetInterval, packetSpace:  For systematic count-based Sampling,
      packetInterval defines the number of packets that are
      consecutively sampled between gaps of length packetSpace.  These
      parameters correspond to the Information Elements
      samplingPacketInterval and samplingPacketSpace [RFC5477], as well
      as to the PSAMP MIB objects psampSampCountBasedInterval and
      psampSampCountBasedSpace [RFC6727].

   timeInterval, timeSpace:  For systematic time-based Sampling,
      timeInterval defines the time interval during which all arriving
      packets are sampled. timeSpace is the gap between two Sampling
      intervals.  These parameters correspond to the Information
      Elements samplingTimeInterval and samplingTimeSpace [RFC5477], as
      well as to the PSAMP MIB objects psampSampTimeBasedInterval and
      psampSampTimeBasedSpace [RFC6727].  The unit is microseconds.

   size, population:  For n-out-of-N random Sampling, size defines the
      number of elements taken from the parent population. population
      defines the number of elements in the parent population.  These
      parameters correspond to the Information Elements samplingSize and
      samplingPopulation [RFC5477], as well as to the PSAMP MIB objects
      psampSampRandOutOfNSize and psampSampRandOutOfNPopulation
      [RFC6727].

   probability:  For uniform probabilistic Sampling, probability defines
      the Sampling probability.  The probability is expressed as a value
      between 0 and 1.  This parameter corresponds to the Information
      Element samplingProbability [RFC5477], as well as to the PSAMP MIB
      object psampSampUniProbProbability [RFC6727].

4.2.3.  Filter Classes

          +---------------------------+
          | FilterMatch               |
          +---------------------------+
          | ieId/ieName               |
          | ieEnterpriseNumber = 0    |
          | value                     |
          +---------------------------+

          +---------------------------+
          | FilterHash                |
          +---------------------------+    1..* +---------------+
          | hashFunction = "BOB"      |<>-------| SelectedRange |
          | initializerValue[0..1]    |         +---------------+
          | ipPayloadOffset = 0       |         | name          |
          | ipPayloadSize = 8         |         | min           |
          | digestOutput = "false"    |         | max           |
          | outputRangeMin {readOnly} |         +---------------+
          | outputRangeMax {readOnly} |
          +---------------------------+

                         Figure 11: Filter classes

   The Filter classes in Figure 11 contain the configuration parameters
   of specific Filtering methods.  For property match Filtering, the
   configuration parameters are:

   ieId, ieName, ieEnterpriseNumber:  The property to be matched is
      specified by either ieId or ieName, specifying the identifier or
      name of the Information Element, respectively.  If
      ieEnterpriseNumber is zero (which is the default), this
      Information Element is registered in the IANA registry of IPFIX
      Information Elements [IANA-IPFIX].  A non-zero value of
      ieEnterpriseNumber specifies an enterprise-specific Information
      Element [IANA-ENTERPRISE-NUMBERS].

   value:  Matching value.

   For hash-based Filtering, the configuration and state parameters are:

   hashFunction:  Hash function to be used.  The following parameter
      values are defined by the configuration data model:
      *  BOB: BOB Hash Function as specified in [RFC5475], Appendix A.2
      *  IPSX: IP Shift-XOR (IPSX) Hash Function as specified in
         [RFC5475], Appendix A.1
      *  CRC: CRC-32 function as specified in [RFC1141]
      Default value is "BOB".  This parameter corresponds to the PSAMP
      MIB object psampFiltHashFunction [RFC6727].

   initializerValue:  Initializer value to the hash function.  This
      parameter corresponds to the Information Element
      hashInitialiserValue [RFC5477], as well as to the PSAMP MIB object
      psampFiltHashInitializerValue [RFC6727].  If not configured by the
      user, the Monitoring Device arbitrarily chooses an initializer
      value.

   ipPayloadOffset, ipPayloadSize:  ipPayloadOffset and ipPayloadSize
      configure the offset and the size of the payload section used as
      input to the hash function.  Default values are 0 and 8,
      respectively, corresponding to the minimum configurable values
      according to [RFC5476], Section 6.5.2.6.  These parameters
      correspond to the Information Elements hashIPPayloadOffset and
      hashIPPayloadSize [RFC5477], as well as to the PSAMP MIB objects
      psampFiltHashIpPayloadOffset and psampFiltHashIpPayloadSize
      [RFC6727].

   digestOutput:  digestOutput enables or disables the inclusion of the
      packet digest in the resulting PSAMP Packet Report.  This requires
      that the Cache Layout of the Cache generating the Packet Reports
      includes a digestHashValue field.  This parameter corresponds to
      the Information Element hashDigestOutput [RFC5477].

   outputRangeMin, outputRangeMax:  The values of these two state
      parameters are the beginning and end of the hash function's
      potential output range.  These parameters correspond to the
      Information Elements hashOutputRangeMin and hashOutputRangeMax
      [RFC5477], as well as to the PSAMP MIB objects
      psampFiltHashOutputRangeMin and psampFiltHashOutputRangeMax
      [RFC6727].

   One or more ranges of matching hash values are defined by the min and
   max parameters of the SelectedRange subclass.  These parameters
   correspond to the Information Elements hashSelectedRangeMin and
   hashSelectedRangeMax [RFC5477], as well as to the PSAMP MIB objects
   psampFiltHashSelectedRangeMin and psampFiltHashSelectedRangeMax
   [RFC6727].

4.3.  Cache Class

    +-----------------------------------+
    | Cache                             |
    +-----------------------------------+        1 +------------------+
    | name                              |<>--------| immediateCache/  |
    | meteringProcessId {readOnly}      |          | timeoutCache/    |
    | dataRecords {readOnly}            |          | naturalCache/    |
    | cacheDiscontinuityTime {readOnly} |          | permanentCache   |
    |                                   |          +------------------+
    |                                   |
    |                                   |     0..* +------------------+
    |                                   |--------->| ExportingProcess |
    +-----------------------------------+          +------------------+

                          Figure 12: Cache class

   Figure 12 shows the Cache class that contains the configuration and
   state parameters of a Cache.  Most of these parameters are specific
   to the type of the Cache and therefore contained in the subclasses
   immediateCache, timeoutCache, naturalCache, and permanentCache, which
   are presented below in Sections 4.3.1 and 4.3.2.  The following three
   state parameters are common to all Caches and therefore included in
   the Cache class itself:

   meteringProcessId:  The identifier of the Metering Process the Cache
      belongs to.
      This parameter corresponds to the Information Element
      meteringProcessId [IANA-IPFIX].  Its occurrence helps to associate
      Metering Process (Reliability) Statistics exported according to
      the IPFIX protocol specification [RFC5101] with the corresponding
      object of the MeteringProcess class.

   dataRecords:  The number of Data Records generated by this Cache.
      Discontinuities in the value of this counter can occur at
      re-initialization of the management system, and at other times as
      indicated by the value of cacheDiscontinuityTime.
      Note that this parameter corresponds to
      ipfixMeteringProcessDataRecords in the IPFIX MIB module [RFC6615].

   cacheDiscontinuityTime:  Timestamp of the most recent occasion at
      which dataRecords suffered a discontinuity.  In contrast to
      ipfixMeteringProcessDiscontinuityTime, the time is absolute and
      not relative to sysUpTime.
      Note that this parameter functionally corresponds to
      ipfixMeteringProcessDiscontinuityTime in the IPFIX MIB module
      [RFC6615].

   A Cache object MAY refer to one or more ExportingProcess objects
   configuring different Exporting Processes.

4.3.1.  ImmediateCache Class

         +-------------------------------+
         | ImmediateCache                |
         +-------------------------------+       1 +-------------+
         |                               |<>-------| CacheLayout |
         +-------------------------------+         +-------------+

                      Figure 13: ImmediateCache class

   The ImmediateCache class depicted in Figure 13 is used to configure a
   Cache that generates a PSAMP Packet Report for each packet at its
   input.  The fields contained in the generated Data Records are
   defined in an object of the CacheLayout class, which is defined below
   in Section 4.3.3.

4.3.2.  TimeoutCache, NaturalCache, and PermanentCache Class

         +-------------------------------+
         | TimeoutCache                  |
         +-------------------------------+       1 +-------------+
         | maxFlows {opt.}               |<>-------| CacheLayout |
         | activeTimeout {opt.}          |         +-------------+
         | idleTimeout {opt.}            |
         | activeFlows {readOnly}        |
         | unusedCacheEntries {readOnly} |
         +-------------------------------+

         +-------------------------------+
         | NaturalCache                  |
         +-------------------------------+       1 +-------------+
         | maxFlows {opt.}               |<>-------| CacheLayout |
         | activeTimeout {opt.}          |         +-------------+
         | idleTimeout {opt.}            |
         | activeFlows {readOnly}        |
         | unusedCacheEntries {readOnly} |
         +-------------------------------+

         +-------------------------------+
         | PermanentCache                |
         +-------------------------------+       1 +-------------+
         | maxFlows {opt.}               |<>-------| CacheLayout |
         | exportInterval {opt.}         |         +-------------+
         | activeFlows {readOnly}        |
         | unusedCacheEntries {readOnly} |
         +-------------------------------+

      Figure 14: TimeoutCache, NaturalCache, and PermanentCache class

   Figure 14 shows the TimeoutCache class, the NaturalCache class, and
   the PermanentCache class.  These classes are used to configure a
   Cache that aggregates the packets at its input and generates IPFIX
   Flow Records.  The three classes differ in when Flows expire:

   o  TimeoutCache: Flows expire after active or idle timeout.
   o  NaturalCache: Flows expire after active or idle timeout, or on
      natural termination (e.g., TCP FIN or TCP RST) of the Flow.
   o  PermanentCache: Flows never expire, but are periodically exported
      with the interval set by exportInterval.

   The following configuration and state parameters are common to the
   three classes:

   maxFlows:  This parameter configures the maximum number of entries in
      the Cache, which is the maximum number of Flows that can be
      measured simultaneously.
      If this parameter is configured, the Monitoring Device MUST ensure
      that sufficient resources are available to store the configured
      maximum number of Flows.  If the maximum number of Cache entries
      is in use, no additional Flows can be measured.  However, traffic
      that pertains to existing Flows can continue to be measured.

   activeFlows:  This state parameter indicates the number of Flows
      currently active in this Cache (i.e., the number of Cache entries
      currently in use).
      Note that this parameter corresponds to
      ipfixMeteringProcessCacheActiveFlows in the IPFIX MIB module
      [RFC6615].

   unusedCacheEntries:  The number of unused cache entries.  Note that
      the sum of activeFlows and unusedCacheEntries equals maxFlows if
      maxFlows is configured.
      Note that this parameter corresponds to
      ipfixMeteringProcessCacheUnusedCacheEntries in the IPFIX MIB
      module [RFC6615].

   The following timeout parameters are only available in the
   TimeoutCache class and the NaturalCache class:

   activeTimeout:  This parameter configures the time in seconds after
      which a Flow is expired even though packets matching this Flow are
      still received by the Cache.  The parameter value zero indicates
      infinity, meaning that there is no active timeout.
      If not configured by the user, the Monitoring Device sets this
      parameter.
      Note that this parameter corresponds to
      ipfixMeteringProcessCacheActiveTimeout in the IPFIX MIB module
      [RFC6615].

   idleTimeout:  This parameter configures the time in seconds after
      which a Flow is expired if no more packets matching this Flow are
      received by the Cache.  The parameter value zero indicates
      infinity, meaning that there is no idle timeout.
      If not configured by the user, the Monitoring Device sets this
      parameter.
      Note that this parameter corresponds to
      ipfixMeteringProcessCacheIdleTimeout in the IPFIX MIB module
      [RFC6615].

   The following interval parameter is only available in the
   PermanentCache class:

   exportInterval:  This parameter configures the interval (in seconds)
      for periodical export of Flow Records.
      If not configured by the user, the Monitoring Device sets this
      parameter.

   Every generated Flow Record MUST be associated with a single
   Observation Domain.  Hence, although a Cache MAY be configured to
   process packets observed at multiple Observation Domains, the Cache
   MUST NOT aggregate packets observed at different Observation Domains
   in the same Flow.

   An object of the Cache class contains an object of the CacheLayout
   class that defines which fields are included in the Flow Records.

4.3.3.  CacheLayout Class

         +--------------+
         | CacheLayout  |
         +--------------+   1..* +--------------------------------+
         |              |<>------| CacheField                     |
         |              |        +--------------------------------+
         |              |        | name                           |
         |              |        | ieId/ieName                    |
         |              |        | ieLength {opt.}                |
         |              |        | ieEnterpriseNumber = 0         |
         |              |        | isFlowKey[0..1] {not used with |
         |              |        |   ImmediateCache class}        |
         +--------------+        +--------------------------------+

                       Figure 15: CacheLayout class

   A Cache generates and maintains Packet Reports or Flow Records
   containing information that has been extracted from the incoming
   stream of packets.  Using the CacheField class, the CacheLayout class
   specifies the superset of fields that are included in the Packet
   Reports or Flow Records (see Figure 15).

   If Packet Reports are generated (i.e., if ImmediateCache class is
   used to configure the Cache), every field specified by the Cache
   Layout MUST be included in the resulting Packet Report unless the
   corresponding Information Element is not applicable or cannot be
   derived from the content or treatment of the incoming packet.  Any
   other field specified by the Cache Layout MAY only be included in the

   Packet Report if it is obvious from the field value itself or from
   the values of other fields in same Packet Report that the field value
   was not determined from the packet.

   For example, if a field is configured to contain the TCP source port
   (Information Element tcpSourcePort [IANA-IPFIX]), the field MUST be
   included in all Packet Reports that are related to TCP packets.
   Although the field value cannot be determined for non-TCP packets,
   the field MAY be included in the Packet Reports if another field
   contains the transport protocol identifier (Information Element
   protocolIdentifier [IANA-IPFIX]).

   If Flow Records are generated (i.e., if TimeoutCache, NaturalCache,
   or PermanentCache class is used to configure the Cache), the Cache
   Layout differentiates between Flow Key fields and non-key fields.
   Every Flow Key field specified by the Cache Layout MUST be included
   as Flow Key in the resulting Flow Record unless the corresponding
   Information Element is not applicable or cannot be derived from the
   content or treatment of the incoming packet.  Any other Flow Key
   field specified by the Cache Layout MAY only be included in the Flow
   Record if it is obvious from the field value itself or from the
   values of other Flow Key fields in the same Flow Record that the
   field value was not determined from the packet.  Two packets are
   accounted by the same Flow Record if none of their Flow Key fields
   differ.  If a Flow Key field can be determined for one packet but not
   for the other, the two packets are accounted in different Flow
   Records.

   Every non-key field specified by the Cache Layout MUST be included in
   the resulting Flow Record unless the corresponding Information
   Element is not applicable or cannot be derived for the given Flow.
   Any other non-key field specified by the Cache Layout MAY only be
   included in the Flow Record if it is obvious from the field value
   itself or from the values of other fields in same Flow Record that
   the field value was not determined from the packet.  Packets which
   are accounted by the same Flow Record may differ in their non-key
   fields, or one or more of the non-key fields can be undetermined for
   all or some of the packets.

   For example, if a non-key field specifies an Information Element
   whose value is determined by the first packet observed within a Flow
   (which is the default rule according to [RFC5102] unless specified
   differently in the description of the Information Element), this
   field MUST be included in the resulting Flow Record if it can be
   determined from the first packet of the Flow.

   The CacheLayout class does not have any parameters.  The
   configuration parameters of the CacheField class are as follows:

   ieId, ieName, ieEnterpriseNumber:  These parameters specify a field
      by the combination of the Information Element identifier or name,
      and the Information Element enterprise number.  Either ieId or
      ieName MUST be specified.  If ieEnterpriseNumber is zero (which is
      the default), this Information Element is registered in the IANA
      registry of IPFIX Information Elements [IANA-IPFIX].  A non-zero
      value of ieEnterpriseNumber specifies an enterprise-specific
      Information Element [IANA-ENTERPRISE-NUMBERS].
      If the enterprise number is set to 29305, this field contains a
      Reverse Information Element.  In this case, the Cache MUST
      generate Data Records in accordance to [RFC5103].

   ieLength:  This parameter specifies the length of the field in
      octets.  A value of 65535 means that the field is encoded as a
      variable-length Information Element.  For Information Elements of
      integer and float type, the field length MAY be set to a smaller
      value than the standard length of the abstract data type if the
      rules of reduced size encoding are fulfilled (see [RFC5101],
      Section 6.2).  If not configured by the user, the field length is
      set by the Monitoring Device.

   isFlowKey:  If present, this field is a Flow Key.  If the field
      contains a Reverse Information Element, it MUST NOT be configured
      as Flow Key.
      This parameter is not available if the Cache is configured using
      the ImmediateCache class since there is no distinction between
      Flow Key fields and non-key fields in Packet Reports.

   Note that the use of Information Elements can be restricted to
   certain Cache types as well as to Flow Key or non-key fields.  Such
   restrictions may result from Information Element definitions or from
   device-specific constraints.  According to Section 5, the Monitoring
   Device MUST notify the user if a Cache field cannot be configured
   with the given Information Element.

4.4.  ExportingProcess Class

     +-------------------------------+
     | ExportingProcess              |
     +-------------------------------+   1..* +-------------+
     | name                          |<>------| Destination |
     | exportingProcessId {readOnly} |        +-------------+
     | exportMode = "parallel"       |        | name        |<>-+
     |                               |        +-------------+   | 1
     |                               |                          |
     |                               |               +---------------+
     |                               |               | SctpExporter/ |
     |                               |               | UdpExporter/  |
     |                               |               | TcpExporter/  |
     |                               |               | FileWriter    |
     |                               |               +---------------+
     |                               |
     |                               |   0..* +------------------+
     |                               |<>------| Options          |
     +-------------------------------+        +------------------+

                     Figure 16: ExportingProcess class

   The ExportingProcess class in Figure 16 specifies destinations to
   which the incoming Packet Reports and Flow Records are exported using
   objects of the Destination class.  The Destination class includes one
   object of the SctpExporter, UdpExporter, TcpExporter, or FileWriter
   class which contains further configuration parameters.  These classes
   are described in Sections 4.4.1, 4.4.2, 4.4.3, and 4.4.4.

   As state parameter, the ExportingProcess class contains the
   identifier of the Exporting Process (exportingProcessId).  This
   parameter corresponds to the Information Element exportingProcessId
   [IANA-IPFIX].  Its occurrence helps to associate Exporting Process
   Reliability Statistics exported according to the IPFIX protocol
   specification [RFC5101] with the corresponding object of the
   ExportingProcess class.

   The order in which objects of the Destination class appear is defined
   by the user.  However, the order has a specific meaning only if the
   exportMode parameter is set to "fallback".  The exportMode parameter
   is defined as follows:

   exportMode:  This parameter determines to which configured
      destination(s) the incoming Data Records are exported.  The
      following parameter values are specified by the configuration data
      model:

      *  parallel: every Data Record is exported to all configured
         destinations in parallel
      *  loadBalancing: every Data Record is exported to exactly one
         configured destination according to a device-specific load-
         balancing policy
      *  fallback: every Data Record is exported to exactly one
         configured destination according to the fallback policy
         described below
      If exportMode is set to "fallback", the first object of the
      Destination class defines the primary destination, the second
      object of the Destination class defines the secondary destination,
      and so on.  If the Exporting Process fails to export Data Records
      to the primary destination, it tries to export them to the
      secondary one.  If the secondary destination fails as well, it
      continues with the tertiary, etc.
      "parallel" is the default value if exportMode is not configured.

   Note that the exportMode parameter is related to the
   ipfixExportMemberType object in [RFC6615].  If exportMode is
   "parallel", the ipfixExportMemberType values of the corresponding
   entries in ipfixExportTable are set to parallel(3).  If exportMode is
   "loadBalancing", the ipfixExportMemberType values of the
   corresponding entries in ipfixExportTable are set to
   loadBalancing(4).  If exportMode is "fallback", the
   ipfixExportMemberType value that refers to the primary destination is
   set to primary(1); the ipfixExportMemberType values that refer to the
   remaining destinations need to be set to secondary(2).  The IPFIX MIB
   module does not define any value for tertiary destination, etc.

   The reporting of information with Options Templates is defined with
   objects of the Options class.

   The Exporting Process may modify the Packet Reports and Flow Records
   to enable a more efficient transmission or storage under the
   condition that no information is changed or suppressed.  For example,
   the Exporting Process may shorten the length of a field according to
   the rules of reduced size encoding [RFC5101].  The Exporting Process
   may also export certain fields in a separate Data Record as described
   in [RFC5476].

4.4.1.  SctpExporter Class

    +------------------------------+
    | SctpExporter                 |
    +------------------------------+    0..1 +------------------------+
    | ipfixVersion = 10            |<>-------| TransportLayerSecurity |
    | sourceIPAddress[0..*]        |         +------------------------+
    | destinationIPAddress[1..*]   |
    | destinationPort = 4739|4740  |    0..1 +------------------------+
    | ifName/ifIndex[0..1]         |<>-------| TransportSession       |
    | sendBufferSize {opt.}        |         +------------------------+
    | rateLimit[0..1]              |
    | timedReliability = 0         |
    +------------------------------+

                       Figure 17: SctpExporter class

   The SctpExporter class shown in Figure 17 contains the configuration
   parameters of an SCTP export destination.  The configuration
   parameters are:

   ipfixVersion:  Version number of the IPFIX protocol used.  If
      omitted, the default value is 10 (=0x000a) as specified in
      [RFC5101].

   sourceIPAddress:  List of source IP addresses used by the Exporting
      Process.  If configured, the specified addresses are eligible
      local IP addresses of the multihomed SCTP endpoint.  If not
      configured, all locally assigned IP addresses are eligible local
      IP addresses.

   destinationIPAddress:  One or more IP addresses of the Collecting
      Process to which IPFIX Messages are sent.  The user must ensure
      that all configured IP addresses belong to the same Collecting
      Process.  The Exporting Process tries to establish an SCTP
      association to any of the configured destination IP addresses.

   destinationPort:  Destination port number to be used.  If not
      configured, standard port 4739 (IPFIX without TLS and DTLS) or
      4740 (IPFIX over TLS or DTLS) is used.

   ifIndex/ifName:  Either the index or the name of the interface used
      by the Exporting Process to export IPFIX Messages to the given
      destination MAY be specified according to corresponding objects in
      the IF-MIB [RFC2863].  If omitted, the Exporting Process selects
      the outgoing interface based on local routing decision and accepts
      return traffic, such as transport-layer acknowledgments, on all
      available interfaces.

   sendBufferSize:  Size of the socket send buffer in bytes.  If not
      configured by the user, the buffer size is set by the Monitoring
      Device.

   rateLimit:  Maximum number of bytes per second the Exporting Process
      may export to the given destination as required by [RFC5476].  The
      number of bytes is calculated from the lengths of the IPFIX
      Messages exported.  If this parameter is not configured, no rate
      limiting is performed for this destination.

   timedReliability:  Lifetime in milliseconds until an IPFIX Message
      containing Data Sets only is "abandoned" due to the timed
      reliability mechanism of the Partial Reliability extension of SCTP
      (PR-SCTP) [RFC3758].  If this parameter is set to zero, reliable
      SCTP transport MUST be used for all Data Records.  Regardless of
      the value of this parameter, the Exporting Process MAY use
      reliable SCTP transport for Data Sets associated with certain
      Options Templates, such as the Data Record Reliability Options
      Template specified in [RFC6526].

   Using the TransportLayerSecurity class described in Section 4.6,
   Datagram Transport Layer Security (DTLS) is enabled and configured
   for this export destination.

   If a Transport Session is established to the configured destination,
   the SctpExporter class includes an object of the TransportSession
   class containing state parameters of the Transport Session.  The
   TransportSession class is specified in Section 4.7.

4.4.2.  UdpExporter Class

    +-------------------------------------+
    | UdpExporter                         |
    +-------------------------------------+   0..1 +------------------+
    | ipfixVersion = 10                   |<>------| TransportLayer-  |
    | sourceIPAddress[0..1]               |        | Security         |
    | destinationIPAddress                |        +------------------+
    | destinationPort = 4739|4740         |
    | ifName/ifIndex[0..1]                |   0..1 +------------------+
    | sendBufferSize {opt.}               |<>------| TransportSession |
    | rateLimit[0..1]                     |        +------------------+
    | maxPacketSize {opt.}                |
    | templateRefreshTimeout = 600        |
    | optionsTemplateRefreshTimeout = 600 |
    | templateRefreshPacket[0..1]         |
    | optionsTemplateRefreshPacket[0..1]  |
    +-------------------------------------+

                       Figure 18: UdpExporter class

   The UdpExporter class shown in Figure 18 contains the configuration
   parameters of a UDP export destination.  The parameters ipfixVersion,
   destinationPort, ifName, ifIndex, sendBufferSize, and rateLimit have
   the same meaning as in the SctpExporter class (see Section 4.4.1).
   The remaining configuration parameters are:

   sourceIPAddress:  This parameter specifies the source IP address used
      by the Exporting Process.  If this parameter is omitted, the IP
      address assigned to the outgoing interface is used as the source
      IP address.

   destinationIPAddress:  Destination IP address to which IPFIX Messages
      are sent (i.e., the IP address of the Collecting Process).

   maxPacketSize:  This parameter specifies the maximum size of IP
      packets sent to the Collector.  If set to zero, the Exporting
      Device MUST derive the maximum packet size from path MTU discovery
      mechanisms.  If not configured by the user, this parameter is set
      by the Monitoring Device.

   templateRefreshTimeout, optionsTemplateRefreshTimeout,
      templateRefreshPacket, optionsTemplateRefreshPacket:  These
      parameters specify when (Options) Templates are refreshed by the
      Exporting Process.
      templateRefreshTimeout and optionsTemplateRefreshTimeout are
      specified in seconds between resendings of (Options) Templates.

      If omitted, the default value of 600 seconds (10 minutes) is used
      [RFC5101].
      templateRefreshPacket and optionsTemplateRefreshPacket specify the
      number of IPFIX Messages after which (Options) Templates are
      resent.  If omitted, the (Options) Templates are only resent after
      timeout.
      Note that the values configured for templateRefreshTimeout and
      optionsTemplateRefreshTimeout MUST be adapted to the
      templateLifeTime and optionsTemplateLifeTime parameter settings at
      the receiving Collecting Process (see Section 4.5.2).
      Note that these parameters correspond to
      ipfixTransportSessionTemplateRefreshTimeout,
      ipfixTransportSessionOptionsTemplateRefreshTimeout,
      ipfixTransportSessionTemplateRefreshPacket, and
      ipfixTransportSessionOptionsTemplateRefreshPacket in the IPFIX MIB
      module [RFC6615].

   Using the TransportLayerSecurity class described in Section 4.6, DTLS
   is enabled and configured for this export destination.

   If a Transport Session is established to the configured destination,
   the UdpExporter class includes an object of the TransportSession
   class containing state parameters of the Transport Session.  The
   TransportSession class is specified in Section 4.7.

4.4.3.  TcpExporter Class

    +------------------------------+
    | TcpExporter                  |
    +------------------------------+    0..1 +------------------------+
    | ipfixVersion = 10            |<>-------| TransportLayerSecurity |
    | sourceIPAddress[0..1]        |         +------------------------+
    | destinationIPAddress         |
    | destinationPort = 4739|4740  |    0..1 +------------------------+
    | ifName/ifIndex[0..1]         |<>-------| TransportSession       |
    | sendBufferSize {opt.}        |         +------------------------+
    | rateLimit[0..1]              |
    +------------------------------+

                       Figure 19: TcpExporter class

   The TcpExporter class shown in Figure 19 contains the configuration
   parameters of a TCP export destination.  The parameters have the same
   meaning as in the UdpExporter class (see Section 4.4.2).

   Using the TransportLayerSecurity class described in Section 4.6,
   Transport Layer Security (TLS) is enabled and configured for this
   export destination.

   If a Transport Session is established to the configured destination,
   the TcpExporter class includes an object of the TransportSession
   class containing state parameters of the Transport Session.  The
   TransportSession class is specified in Section 4.7.

4.4.4.  FileWriter Class

      +-----------------------------------------+
      | FileWriter                              |
      +-----------------------------------------+    0..* +----------+
      | ipfixVersion = 10                       |<>-------| Template |
      | file                                    |         +----------+
      | status {readOnly}                       |
      | bytes {readOnly}                        |
      | messages {readOnly}                     |
      | discardedMessages {readOnly}            |
      | records {readOnly}                      |
      | templates {readOnly}                    |
      | optionsTemplates {readOnly}             |
      | fileWriterDiscontinuityTime {readOnly}  |
      +-----------------------------------------+

                       Figure 20: FileWriter classes

   If an object of the FileWriter class is included in an object of the
   Destination class, IPFIX Messages are written into a file as
   specified in [RFC5655].  The FileWriter class contains the following
   configuration parameters:

   ipfixVersion:  Version number of the IPFIX protocol used.  If
      omitted, the default value is 10 (=0x000a) as specified in
      [RFC5101].

   file:  File name and location specified as URI.

   The state parameters of the FileWriter class are:

   bytes, messages, records, templates, optionsTemplates:  The number of
      bytes, IPFIX Messages, Data Records, Template Records, and Options
      Template Records written by the File Writer.  Discontinuities in
      the values of these counters can occur at re-initialization of the
      management system, and at other times as indicated by the value of
      fileWriterDiscontinuityTime.

   discardedMessages:  The number of IPFIX Messages that could not be
      written by the File Writer due to internal buffer overflows,
      limited storage capacity, etc.  Discontinuities in the value of
      this counter can occur at re-initialization of the management
      system, and at other times as indicated by the value of
      fileWriterDiscontinuityTime.

   fileWriterDiscontinuityTime:  Timestamp of the most recent occasion
      at which one or more File Writer counters suffered a
      discontinuity.  In contrast to discontinuity times in the IPFIX
      MIB module, the time is absolute and not relative to sysUpTime.

   Each object of the FileWriter class includes a list of objects of the
   Template class with information and statistics about the Templates
   written to the file.  The Template class is specified in Section 4.8.

4.4.5.  Options Class

                         +-----------------------+
                         | Options               |
                         +-----------------------+
                         | name                  |
                         | optionsType           |
                         | optionsTimeout {opt.} |
                         +-----------------------+

                         Figure 21: Options class

   The Options class in Figure 21 defines the type of specific
   information to be reported, such as statistics, flow keys, Sampling
   and Filtering parameters, etc.  [RFC5101] and [RFC5476] specify
   several types of reporting information that may be exported.  The
   following parameter values are specified by the configuration data
   model:

   meteringStatistics:  Export of Metering Process statistics using the
      Metering Process Statistics Options Template [RFC5101].

   meteringReliability:  Export of Metering Process reliability
      statistics using the Metering Process Reliability Statistics
      Options Template [RFC5101].

   exportingReliability:  Export of Exporting Process reliability
      statistics using the Exporting Process Reliability Statistics
      Options Template [RFC5101].

   flowKeys:  Export of the Flow Key specification using the Flow Keys
      Options Template [RFC5101].

   selectionSequence:  Export of Selection Sequence Report
      Interpretation and Selector Report Interpretation [RFC5476].

   selectionStatistics:  Export of Selection Sequence Statistics Report
      Interpretation [RFC5476].

   accuracy:  Export of Accuracy Report Interpretation [RFC5476].

   reducingRedundancy:  Enables the utilization of Options Templates to
      reduce redundancy in the exported Data Records according to
      [RFC5473].  The Exporting Process decides when to apply these
      Options Templates.

   extendedTypeInformation:  Export of extended type information for
      enterprise-specific Information Elements used in the exported
      Templates [RFC5610].

   The Exporting Process MUST choose a Template definition according to
   the options type and available options data.

   The optionsTimeout parameter specifies the reporting interval (in
   milliseconds) for periodic export of the option data.  A parameter
   value of zero means that the export of the option data is not
   triggered periodically, but whenever the available option data has
   changed.  This is the typical setting for options types flowKeys,
   selectionSequence, accuracy, and reducingRedundancy.  If
   optionsTimeout is not configured by the user, it is set by the
   Monitoring Device.

4.5.  CollectingProcess Class

           +-------------------+
           | CollectingProcess |
           +-------------------+
           | name              |       0..* +------------------+
           |                   |<>----------| SctpCollector    |
           |                   |            +------------------+
           |                   |
           |                   |       0..* +------------------+
           |                   |<>----------| UdpCollector     |
           |                   |            +------------------+
           |                   |
           |                   |       0..* +------------------+
           |                   |<>----------| TcpCollector     |
           |                   |            +------------------+
           |                   |
           |                   |       0..* +------------------+
           |                   |<>----------| FileReader       |
           |                   |            +------------------+
           |                   |
           |                   | 0..*  0..* +------------------+
           |                   |----------->| ExportingProcess |
           +-------------------+            +------------------+

                    Figure 22: CollectingProcess class

   Figure 22 shows the CollectingProcess class that contains the
   configuration and state parameters of a Collecting Process.  Objects
   of the SctpCollector, UdpCollector, and TcpCollector classes specify
   how IPFIX Messages are received from remote Exporters.  The
   Collecting Process can also be configured as a File Reader using
   objects of the FileReader class.  These classes are described in
   Sections 4.5.1, 4.5.2, 4.5.3, and 4.5.4.

   A CollectingProcess object MAY refer to one or more ExportingProcess
   objects configuring Exporting Processes that export the received data
   without modifications to a file or to another Collector.

4.5.1.  SctpCollector Class

      +--------------------------+
      | SctpCollector            |
      +--------------------------+    0..1 +------------------------+
      | name                     |<>-------| TransportLayerSecurity |
      | localIPAddress[0..*]     |         +------------------------+
      | localPort = 4739|4740    |
      |                          |    0..* +------------------------+
      |                          |<>-------| TransportSession       |
      +--------------------------+         +------------------------+

                      Figure 23: SctpCollector class

   The SctpCollector class contains the configuration parameters of a
   listening SCTP socket at a Collecting Process.  The parameters are:

   localIPAddress:  List of local IP addresses on which the Collecting
      Process listens for IPFIX Messages.  The IP addresses are used as
      eligible local IP addresses of the multihomed SCTP endpoint
      [RFC4960].  If omitted, the Collecting Process listens on all
      local IP addresses.

   localPort:  Local port number on which the Collecting Process listens
      for IPFIX Messages.  If omitted, standard port 4739 (IPFIX without
      TLS and DTLS) or 4740 (IPFIX over TLS or DTLS) is used.

   Using the TransportLayerSecurity class described in Section 4.6, DTLS
   is enabled and configured for this receiving socket.

   As state data, the SctpCollector class contains the list of currently
   established Transport Sessions that terminate at the given SCTP
   socket of the Collecting Process.  The TransportSession class is
   specified in Section 4.7.

4.5.2.  UdpCollector Class

   +---------------------------------+
   | UdpCollector                    |
   +---------------------------------+   0..1 +------------------------+
   | name                            |<>------| TransportLayerSecurity |
   | localIPAddress[0..*]            |        +------------------------+
   | localPort = 4739|4740           |
   | templateLifeTime = 1800         |   0..* +------------------------+
   | optionsTemplateLifeTime = 1800  |<>------| TransportSession       |
   | templateLifePacket[0..*]        |        +------------------------+
   | optionsTemplateLifePacket[0..*] |
   +---------------------------------+

                       Figure 24: UdpCollector class

   The UdpCollector class contains the configuration parameters of a
   listening UDP socket at a Collecting Process.  The parameter
   localPort has the same meaning as in the SctpCollector class (see
   Section 4.5.1).  The remaining parameters are:

   localIPAddress:  List of local IP addresses on which the Collecting
      Process listens for IPFIX Messages.  If omitted, the Collecting
      Process listens on all local IP addresses.

   templateLifeTime, optionsTemplateLifeTime:  (Options) Template
      lifetime in seconds for all UDP Transport Sessions terminating at
      this UDP socket.  (Options) Templates that are not received again
      within the configured lifetime become invalid at the Collecting
      Process.
      As specified in [RFC5101], Section 10.3.7, the lifetime of
      Templates and Options Templates MUST be at least three times
      higher than the templateRefreshTimeout and
      optionTemplatesRefreshTimeout parameter values configured on the
      corresponding Exporting Processes.
      If not configured, the default value 1800 is used, which is three
      times the default (Options) Template refresh timeout (see
      Section 4.4.2) as specified in [RFC5101].
      Note that these parameters correspond to
      ipfixTransportSessionTemplateRefreshTimeout and
      ipfixTransportSessionOptionsTemplateRefreshTimeout in the IPFIX
      MIB module [RFC6615].

   templateLifePacket, optionsTemplateLifePacket:  If templateLifePacket
      is configured, Templates defined in a UDP Transport Session become
      invalid if they are neither included in a sequence of more than
      this number of IPFIX Messages nor received again within the period
      of time specified by templateLifeTime.  Similarly, if

      optionsTemplateLifePacket is configured, Options Templates become
      invalid if they are neither included in a sequence of more than
      this number of IPFIX Messages nor received again within the period
      of time specified by optionsTemplateLifeTime.
      If not configured, Templates and Options Templates only become
      invalid according to the lifetimes specified by templateLifeTime
      and optionsTemplateLifeTime, respectively.
      Note that these parameters correspond to
      ipfixTransportSessionTemplateRefreshPacket and
      ipfixTransportSessionOptionsTemplateRefreshPacket in the IPFIX MIB
      module [RFC6615].

   Using the TransportLayerSecurity class described in Section 4.6, DTLS
   is enabled and configured for this receiving socket.

   As state data, the UdpCollector class contains the list of currently
   established Transport Sessions that terminate at the given UDP socket
   of the Collecting Process.  The TransportSession class is specified
   in Section 4.7.

4.5.3.  TcpCollector Class

      +--------------------------+
      | TcpCollector             |
      +--------------------------+    0..1 +------------------------+
      | name                     |<>-------| TransportLayerSecurity |
      | localIPAddress[0..*]     |         +------------------------+
      | localPort = 4739|4740    |
      |                          |    0..* +------------------------+
      |                          |<>-------| TransportSession       |
      +--------------------------+         +------------------------+

                       Figure 25: TcpCollector class

   The TcpCollector class contains the configuration parameters of a
   listening TCP socket at a Collecting Process.  The parameters have
   the same meaning as in the UdpCollector class (see Section 4.5.2).

   Using the TransportLayerSecurity class described in Section 4.6, TLS
   is enabled and configured for this receiving socket.

   As state data, the TcpCollector class contains the list of currently
   established Transport Sessions that terminate at the given TCP socket
   of the Collecting Process.  The TransportSession class is specified
   in Section 4.7.

4.5.4.  FileReader Class

      +-----------------------------------------+
      | FileReader                              |
      +-----------------------------------------+    0..* +----------+
      | name                                    |<>-------| Template |
      | file                                    |         +----------+
      | bytes {readOnly}                        |
      | messages {readOnly}                     |
      | records {readOnly}                      |
      | templates {readOnly}                    |
      | optionsTemplates {readOnly}             |
      | fileReaderDiscontinuityTime {readOnly}  |
      +-----------------------------------------+

                       Figure 26: FileReader classes

   The Collecting Process may import IPFIX Messages from a file as
   specified in [RFC5655].  The FileReader class defines the following
   configuration parameter:

   file:  File name and location specified as URI.

   The state parameters of the FileReader class are:

   bytes, messages, records, templates, optionsTemplates:  The number of
      bytes, IPFIX Messages, Data Records, Template Records, and Options
      Template Records read by the File Reader.  Discontinuities in the
      values of these counters can occur at re-initialization of the
      management system, and at other times as indicated by the value of
      fileReaderDiscontinuityTime.

   fileReaderDiscontinuityTime:  Timestamp of the most recent occasion
      at which one or more File Reader counters suffered a
      discontinuity.  In contrast to discontinuity times in the IPFIX
      MIB module, the time is absolute and not relative to sysUpTime.

   Each object of the FileReader class includes a list of objects of the
   Template class with information and statistics about the Templates
   read from the file.  The Template class is specified in Section 4.8.

4.6.  Transport Layer Security Class

                  +--------------------------------------+
                  | TransportLayerSecurity               |
                  +--------------------------------------+
                  | localCertificationAuthorityDN[0..*]  |
                  | localSubjectDN[0..*]                 |
                  | localSubjectFQDN[0..*]               |
                  | remoteCertificationAuthorityDN[0..*] |
                  | remoteSubjectDN[0..*]                |
                  | remoteSubjectFQDN[0..*]              |
                  +--------------------------------------+

                  Figure 27: TransportLayerSecurity class

   The TransportLayerSecurity class is used in the Exporting Process's
   SctpExporter, UdpExporter, and TcpExporter classes, and the
   Collecting Process's SctpCollector, UdpCollector, and TcpCollector
   classes to enable and configure TLS/DTLS for IPFIX.  TLS/DTLS can be
   enabled without configuring any additional parameters.  In this case,
   an empty XML element <transportLayerSecurity /> appears in the
   configuration.  If TLS/DTLS is enabled, the endpoint must use DTLS
   [RFC6347] if the transport protocol is SCTP or UDP, and TLS [RFC5246]
   if the transport protocol is TCP.

   [RFC5101] mandates strong mutual authentication of Exporting
   Processes and Collecting Process as follows.  Note this text cites
   [RFC3280], which was obsoleted by [RFC5280].

      IPFIX Exporting Processes and IPFIX Collecting Processes are
      identified by the fully qualified domain name (FQDN) of the
      interface on which IPFIX Messages are sent or received, for
      purposes of X.509 client and server certificates as in [RFC3280].
      To prevent man-in-the-middle attacks from impostor Exporting or
      Collecting Processes, the acceptance of data from an unauthorized
      Exporting Process, or the export of data to an unauthorized
      Collecting Process, strong mutual authentication via asymmetric
      keys MUST be used for both TLS and DTLS.  Each of the IPFIX
      Exporting and Collecting Processes MUST verify the identity of its
      peer against its authorized certificates, and MUST verify that the
      peer's certificate matches its fully qualified domain name, or, in
      the case of SCTP, the fully qualified domain name of one of its
      endpoints.
      The fully qualified domain name used to identify an IPFIX
      Collecting Process or Exporting Process may be stored either in a
      subjectAltName extension of type dNSName, or in the most specific
      Common Name field of the Subject field of the X.509 certificate.

      If both are present, the subjectAltName extension is given
      preference.

   In order to use TLS/DTLS, appropriate certificates and keys have to
   be previously installed on the Monitoring Devices.  For security
   reasons, the configuration data model does not offer the possibility
   to upload any certificates or keys on a Monitoring Device.  If TLS/
   DTLS is enabled on a Monitoring Device that does not dispose of
   appropriate certificates and keys, the configuration MUST be rejected
   with an error.

   The configuration data model allows restricting the authorization of
   remote endpoints to certificates issued by specific certification
   authorities or identifying specific FQDNs for authorization.
   Furthermore, the configuration data model allows restricting the
   utilization of certificates identifying the local endpoint.  This is
   useful if the Monitoring Device disposes of more than one certificate
   for the given local endpoint.

   The configuration parameters are defined as follows:

   localCertificationAuthorityDN:  This parameter MAY appear one or more
      times to restrict the identification of the local endpoint during
      the TLS/DTLS handshake to certificates issued by the configured
      certification authorities.  Each occurrence of this parameter
      contains the distinguished name of one certification authority.
      To identify the local endpoint, the Exporting Process or
      Collecting Process MUST use a certificate issued by one of the
      configured certification authorities.  Certificates issued by any
      other certification authority MUST NOT be sent to the remote peer
      during TLS/DTLS handshake.  If none of the certificates installed
      on the Monitoring Device fulfills the specified restrictions, the
      configuration MUST be rejected with an error.
      If localCertificationAuthorityDN is not configured, the choice of
      certificates identifying the local endpoint is not restricted with
      respect to the issuing certification authority.

   localSubjectDN, localSubjectFQDN:  Each of these parameters MAY
      appear one or more times to restrict the identification of the
      local endpoint during the TLS/DTLS handshake to certificates
      issued for specific subjects or for specific FQDNs.  Each
      occurrence of localSubjectDN contains a distinguished name
      identifying the local endpoint.  Each occurrence of
      localSubjectFQDN contains a FQDN which is assigned to the local
      endpoint.
      To identify the local endpoint, the Exporting Process or
      Collecting Process MUST use a certificate that contains either one
      of the configured distinguished names in the subject field or at

      least one of the configured FQDNs in a dNSName component of the
      subject alternative extension field or in the most specific
      commonName component of the subject field.  If none of the
      certificates installed on the Monitoring Device fulfills the
      specified restrictions, the configuration MUST be rejected with an
      error.
      If any of the parameters localSubjectDN and localSubjectFQDN is
      configured at the same time as the localCertificationAuthorityDN
      parameter, certificates MUST also fulfill the specified
      restrictions regarding the certification authority.
      If localSubjectDN and localSubjectFQDN are not configured, the
      choice of certificates identifying the local endpoint is not
      restricted with respect to the subject's distinguished name or
      FQDN.

   remoteCertificationAuthorityDN:  This parameter MAY appear one or
      more times to restrict the authentication of remote endpoints
      during the TLS/DTLS handshake to certificates issued by the
      configured certification authorities.  Each occurrence of this
      parameter contains the distinguished name of one certification
      authority.
      To authenticate the remote endpoint, the remote Exporting Process
      or Collecting Process MUST provide a certificate issued by one of
      the configured certification authorities.  Certificates issued by
      any other certification authority MUST be rejected during TLS/DTLS
      handshake.
      If the Monitoring Device is not able to validate certificates
      issued by the configured certification authorities (e.g., because
      of missing public keys), the configuration must be rejected with
      an error.
      If remoteCertificationAuthorityDN is not configured, the
      authorization of remote endpoints is not restricted with respect
      to the issuing certification authority of the delivered
      certificate.

   remoteSubjectDN, remoteSubjectFQDN:  Each of these parameters MAY
      appear one or more times to restrict the authentication of remote
      endpoints during the TLS/DTLS handshake to certificates issued for
      specific subjects or for specific FQDNs.  Each occurrence of
      remoteSubjectDN contains a distinguished name identifying a remote
      endpoint.  Each occurrence of remoteSubjectFQDN contains a FQDN
      that is assigned to a remote endpoint.
      To authenticate a remote endpoint, the remote Exporting Process or
      Collecting Process MUST provide a certificate that contains either
      one of the configured distinguished names in the subject field or
      at least one of the configured FQDNs in a dNSName component of the
      subject alternative extension field or in the most specific
      commonName component of the subject field.  Certificates not

      fulfilling this condition MUST be rejected during TLS/DTLS
      handshake.
      If any of the parameters remoteSubjectDN and remoteSubjectFQDN is
      configured at the same time as the remoteCertificationAuthorityDN
      parameter, certificates MUST also fulfill the specified
      restrictions regarding the certification authority in order to be
      accepted.
      If remoteSubjectDN and remoteSubjectFQDN are not configured, the
      authorization of remote endpoints is not restricted with respect
      to the subject's distinguished name or FQDN of the delivered
      certificate.

4.7.  Transport Session Class

   +----------------------------------------------+
   | TransportSession                             |
   +----------------------------------------------+    0..* +----------+
   | ipfixVersion {readOnly}                      |<>-------| Template |
   | sourceAddress {readOnly}                     |         +----------+
   | destinationAddress {readOnly}                |
   | sourcePort {readOnly}                        |
   | destinationPort {readOnly}                   |
   | sctpAssocId {readOnly} {SCTP only}           |
   | status {readOnly}                            |
   | rate {readOnly}                              |
   | bytes {readOnly}                             |
   | messages {readOnly}                          |
   | discardedMessages {readOnly}                 |
   | records {readOnly}                           |
   | templates {readOnly}                         |
   | optionsTemplates {readOnly}                  |
   | transportSessionStartTime {readOnly}         |
   | transportSessionDiscontinuityTime {readOnly} |
   +----------------------------------------------+

                     Figure 28: TransportSession class

   The TransportSession class contains state data about Transport
   Sessions originating from an Exporting Process or terminating at a
   Collecting Process.  In general, the state parameters correspond to
   the managed objects in the ipfixTransportSessionTable and
   ipfixTransportSessionStatsTable of the IPFIX MIB module [RFC6615].
   An exception is the usage of the parameters sourceAddress and
   destinationAddress.  If SCTP is the transport protocol, the Exporter
   or Collector MAY be multihomed SCTP endpoints (see [RFC4960], Section
   6.4) and use more than one IP address.  In the IPFIX MIB module,
   ipfixTransportSessionSctpAssocId is used instead of
   ipfixTransportSessionSourceAddress and

   ipfixTransportSessionDestinationAddress to point to an entry in the
   sctpAssocTable defined in the SCTP MIB module [RFC3871].  Since we
   cannot assume that an SNMP agent offering access to the SCTP MIB
   module exists on the Monitoring Device, the configuration data model
   cannot rely on this parameter.  Therefore, the state parameters
   sourceAddress and destinationAddress are used for SCTP as well,
   containing one of the potentially many Exporter and Collector IP
   addresses in the SCTP association.  Preferably, the IP addresses of
   the path that is usually selected by the Exporter to send IPFIX
   Messages to the Collector SHOULD be contained.

   Several MIB objects of the ipfixTransportSessionTable are omitted in
   the TransportSession class.  The MIB object
   ipfixTransportSessionDeviceMode is not included because its value can
   be derived from the context in which a TransportSession object
   appears: exporting(1) if it belongs to an Exporting Process,
   collecting(2) if it belongs to a Collecting Process.  Similarly, the
   MIB object ipfixTransportSessionProtocol is not included as the
   transport protocol is known from the context as well.  The MIB
   objects ipfixTransportSessionTemplateRefreshTimeout,
   ipfixTransportSessionOptionsTemplateRefreshTimeout,
   ipfixTransportSessionTemplateRefreshPacket, and
   ipfixTransportSessionOptionsTemplateRefreshPacket are not included
   since they correspond to configuration parameters of the UdpExporter
   class (templateRefreshTimeout, optionsTemplateRefreshTimeout,
   templateRefreshPacket, optionsTemplateRefreshPacket) and the
   UdpCollector class (templateLifeTime, optionsTemplateLifeTime,
   templateLifePacket, optionsTemplateLifePacket).

   ipfixVersion:  Used for Exporting Processes, this parameter contains
      the version number of the IPFIX protocol that the Exporter uses to
      export its data in this Transport Session.  Hence, it is identical
      to the value of the configuration parameter ipfixVersion of the
      outer SctpExporter, UdpExporter, or TcpExporter object.
      Used for Collecting Processes, this parameter contains the version
      number of the IPFIX protocol it receives for this Transport
      Session.  If IPFIX Messages of different IPFIX protocol versions
      are received, this parameter contains the maximum version number.
      This state parameter is identical to
      ipfixTransportSessionIpfixVersion in the IPFIX MIB module
      [RFC6615].

   sourceAddress, destinationAddress:  If TCP or UDP is the transport
      protocol, sourceAddress contains the IP address of the Exporter,
      and destinationAddress contains the IP addresses of the Collector.
      Hence, the two parameters have identical values as
      ipfixTransportSessionSourceAddress and
      ipfixTransportSessionDestinationAddress in the IPFIX MIB module
      [RFC6615].
      If SCTP is the transport protocol, sourceAddress contains one of
      the IP addresses of the Exporter and destinationAddress one of the
      IP addresses of the Collector.  Preferably, the IP addresses of
      the path that is usually selected by the Exporter to send IPFIX
      Messages to the Collector SHOULD be contained.

   sourcePort, destinationPort:  These state parameters contain the
      transport-protocol port numbers of the Exporter and the Collector
      of the Transport Session and thus are identical to
      ipfixTransportSessionSourcePort and
      ipfixTransportSessionDestinationPort in the IPFIX MIB module
      [RFC6615].

   sctpAssocId:  The association ID used for the SCTP session between
      the Exporter and the Collector of the Transport Session.  It is
      equal to the sctpAssocId entry in the sctpAssocTable defined in
      the SCTP-MIB [RFC3871].
      This parameter is only available if the transport protocol is SCTP
      and if an SNMP agent on the same Monitoring Device enables access
      to the corresponding MIB objects in the sctpAssocTable.
      This state parameter is identical to
      ipfixTransportSessionSctpAssocId in the IPFIX MIB module
      [RFC6615].

   status:  Status of the Transport Session, which can be one of the
      following:
      *  inactive: Transport Session is established, but no IPFIX
         Messages are currently transferred (e.g., because this is a
         backup (secondary) session)
      *  active: Transport Session is established and transfers IPFIX
         Messages
      *  unknown: Transport Session status cannot be determined
      This state parameter is identical to ipfixTransportSessionStatus
      in the IPFIX MIB module [RFC6615].

   rate:  The number of bytes per second transmitted by the Exporting
      Process or received by the Collecting Process.  This parameter is
      updated every second.
      This state parameter is identical to ipfixTransportSessionRate in
      the IPFIX MIB module [RFC6615].

   bytes, messages, records, templates, optionsTemplates:  The number of
      bytes, IPFIX Messages, Data Records, Template Records, and Options
      Template Records transmitted by the Exporting Process or received
      by the Collecting Process.  Discontinuities in the values of these
      counters can occur at re-initialization of the management system,
      and at other times as indicated by the value of
      transportSessionDiscontinuityTime.

   discardedMessages:  Used for Exporting Processes, this parameter
      indicates the number of messages that could not be sent due to
      internal buffer overflows, network congestion, routing issues,
      etc.
      Used for Collecting Process, this parameter indicates the number
      of received IPFIX Messages that are malformed, cannot be decoded,
      are received in the wrong order or are missing according to the
      sequence number.
      Discontinuities in the value of this counter can occur at
      re-initialization of the management system, and at other times as
      indicated by the value of transportSessionDiscontinuityTime.

   transportSessionStartTime:  Timestamp of the start of the given
      Transport Session.
      This state parameter does not correspond to any object in the
      IPFIX MIB module.

   transportSessionDiscontinuityTime:  Timestamp of the most recent
      occasion at which one or more of the Transport Session counters
      suffered a discontinuity.  In contrast to
      ipfixTransportSessionDiscontinuityTime, the time is absolute and
      not relative to sysUpTime.

   Note that, if used for Exporting Processes, the values of the state
   parameters destinationAddress and destinationPort match the values of
   the configuration parameters destinationIPAddress and destinationPort
   of the outer SctpExporter, TcpExporter, and UdpExporter objects (in
   the case of SctpExporter, one of the configured destinationIPAddress
   values); if the transport protocol is UDP or SCTP and if the
   parameter sourceIPAddress is configured in the outer UdpExporter or
   SctpExporter object, the value of sourceAddress equals the configured
   value or one of the configured values.  Used for Collecting
   Processes, the value of destinationAddress equals the value (or one
   of the values) of the parameter localIPAddress if this parameter is
   configured in the outer UdpCollector, TcpCollector, or SctpCollector
   object; destinationPort equals the value of the configuration
   parameter localPort.

   Each object of the TransportSession class includes a list of objects
   of the Template class with information and statistics about the
   Templates transmitted or received on the given Transport Session.
   The Template class is specified in Section 4.8.

4.8.  Template Class

     +--------------------------------------+
     | Template                             |
     +--------------------------------------+
     | observationDomainId {readOnly}       |<>---+ 0..*
     | templateId {readOnly}                |     |
     | setId {readOnly}                     |     |
     | accessTime {readOnly}                |     |
     | templateDataRecords {readOnly}       |     |
     | templateDiscontinuityTime {readOnly} |     |
     +--------------------------------------+     |
                                                  |
                              +--------------------------------------+
                              | Field                                |
                              +--------------------------------------+
                              | ieId {readOnly}                      |
                              | ieLength {readOnly}                  |
                              | ieEnterpriseNumber {readOnly}        |
                              | isFlowKey {readOnly} {non-Options    |
                              |   Template only}                     |
                              | isScope {readOnly} {Options Template |
                              |   only}                              |
                              +--------------------------------------+

                         Figure 29: Template class

   The Template class contains state data about Templates used by an
   Exporting Process or received by a Collecting Process in a specific
   Transport Session.  The Field class defines one field of the
   Template.  The names and semantics of the state parameters correspond
   to the managed objects in the ipfixTemplateTable,
   ipfixTemplateDefinitionTable, and ipfixTemplateStatsTable of the
   IPFIX MIB module [RFC6615]:

   observationDomainId:  The ID of the Observation Domain for which this
      Template is defined.

   templateId:  This number indicates the Template ID in the IPFIX
      Message.

   setId:  This number indicates the Set ID of the Template.
      Currently, there are two values defined [RFC5101].  The value 2 is
      used for Sets containing Template definitions.  The value 3 is
      used for Sets containing Options Template definitions.

   accessTime:  Used for Exporting Processes, this parameter contains
      the time when this (Options) Template was last sent to the
      Collector or written to the file.
      Used for Collecting Processes, this parameter contains the time
      when this (Options) Template was last received from the Exporter
      or read from the file.

   templateDataRecords:  The number of transmitted or received Data
      Records defined by this (Options) Template since the point in time
      indicated by templateDefinitionTime.

   templateDiscontinuityTime:  Timestamp of the most recent occasion at
      which the counter templateDataRecords suffered a discontinuity.
      In contrast to ipfixTemplateDiscontinuityTime, the time is
      absolute and not relative to sysUpTime.

   ieId, ieLength, ieEnterpriseNumber:  Information Element identifier,
      length, and enterprise number of a field in the Template.  If this
      is not an enterprise-specific Information Element,
      ieEnterpriseNumber is zero.
      These state parameters are identical to
      ipfixTemplateDefinitionIeId, ipfixTemplateDefinitionIeLength, and
      ipfixTemplateDefinitionIeEnterpriseNumber in the IPFIX MIB module
      [RFC6615].

   isFlowKey:  If this state parameter is present, this is a Flow Key
      field.
      This parameter is only available for non-Options Templates (i.e.,
      if setId is 2).

   isFlowKey:  If this state parameter is present, this is a scope
      field.
      This parameter is only available for Options Templates (i.e., if
      setId is 3).

5.  Adaptation to Device Capabilities

   The configuration data model standardizes a superset of common IPFIX
   and PSAMP configuration parameters.  A typical Monitoring Device
   implementation will not support the entire range of possible
   configurations.  Certain functions may not be supported, such as the
   Collecting Process that does not exist on a Monitoring Device that is
   conceived as Exporter only.  The configuration of other functions may

   be subject to resource limitations or functional restrictions.  For
   example, the Cache size is typically limited according to the
   available memory on the device.  It is also possible that a
   Monitoring Device implementation requires the configuration of
   additional parameters that are not part of the configuration data
   model in order to function properly.

   YANG [RFC6020] offers several possibilities to restrict and adapt a
   configuration data model.  The current version of YANG defines the
   concepts of features, deviations, and extensions.

   The feature concept allows the author of a configuration data model
   to make proportions of the model conditional in a manner that is
   controlled by the device.  Devices do not have to support these
   conditional parts to conform to the model.  If the NETCONF protocol
   is used, features which are supported by the device are announced in
   the <hello> message [RFC6241].

   The configuration data model for IPFIX and PSAMP covers the
   configuration of Exporters, Collectors, and devices that may act as
   both.  As Exporters and Collectors implement different functions, the
   corresponding proportions of the model are conditional on the
   following features:

   exporter:  If this feature is supported, Exporting Processes can be
      configured.

   collector:  If this feature is supported, Collecting Processes can be
      configured.

   Exporters do not necessarily implement any Selection Processes,
   Caches, or even Observation Points in particular cases.  Therefore,
   the corresponding proportions of the model are conditional on the
   following feature:

   meter:  If this feature is supported, Observation Points, Selection
      Processes, and Caches can be configured.

   Additional features refer to different PSAMP Sampling and Filtering
   methods as well as to the supported types of Caches:

   psampSampCountBased:  If this feature is supported, Sampling method
      sampCountBased can be configured.

   psampSampTimeBased:  If this feature is supported, Sampling method
      sampTimeBased can be configured.

   psampSampRandOutOfN:  If this feature is supported, Sampling method
      sampRandOutOfN can be configured.

   psampSampUniProb:  If this feature is supported, Sampling method
      sampUniProb can be configured.

   psampFilterMatch:  If this feature is supported, Filtering method
      filterMatch can be configured.

   psampFilterHash:  If this feature is supported, Filtering method
      filterHash can be configured.

   immediateCache:  If this feature is supported, a Cache generating
      PSAMP Packet Reports can be configured using the ImmediateCache
      class.

   timeoutCache:  If this feature is supported, a Cache generating IPFIX
      Flow Records can be configured using the TimeoutCache class.

   naturalCache:  If this feature is supported, a Cache generating IPFIX
      Flow Records can be configured using the NaturalCache class.

   permanentCache:  If this feature is supported, a Cache generating
      IPFIX Flow Records can be configured using the PermanentCache
      class.

   The following features concern the support of UDP and TCP as
   transport protocols and the support of File Readers and File Writers:

   udpTransport:  If this feature is supported, UDP can be used as
      transport protocol by Exporting Processes and Collecting
      Processes.

   tcpTransport:  If this feature is supported, TCP can be used as
      transport protocol by Exporting Processes and Collecting
      Processes.

   fileReader:  If this feature is supported, File Readers can be
      configured as part of Collecting Processes.

   fileWriter:  If this feature is supported, File Writers can be
      configured as part of Exporting Processes.

   The deviation concept enables a device to announce deviations from
   the standard model using the "deviation" statement.  For example, it
   is possible to restrict the value range of a specific parameter or to
   define that the configuration of a certain parameter is not supported
   at all.  Hence, deviations are typically used to specify limitations

   due to resource constraints or functional restrictions.  Deviations
   concern existing parameters of the original configuration data model
   and must not be confused with model extensions.  Model extensions are
   specified with the "augment" statement and allow adding new
   parameters to the original configuration data model.

   If certain device-specific constraints cannot be formally specified
   with YANG, they MUST be expressed with human-readable text using the
   "description" statement.  The provided information MUST enable the
   user to define a configuration that is entirely supported by the
   Monitoring Device.  On the other hand, if a Monitoring Device is
   configured, it MUST notify the user about any part of the
   configuration that is not supported.  The Monitoring Device MUST NOT
   silently accept configuration data that cannot be completely
   enforced.  If the NETCONF protocol is used to send configuration data
   to the Monitoring Device, the error handling is specified in the
   NETCONF protocol specification [RFC6241].

   Just like features, deviations and model extensions are announced in
   NETCONF's <hello> message.  A usage example of deviations is given in
   Section 7.5.

6.  YANG Module of the IPFIX/PSAMP Configuration Data Model

   The YANG module specification of the configuration data model is
   listed below.  It makes use of the common YANG types defined in the
   modules urn:ietf:params:xml:ns:yang:ietf-yang-types and
   urn:ietf:params:xml:ns:yang:ietf-inet-types [RFC6021].

  <CODE BEGINS> file "ietf-ipfix-psamp@2012-09-05.yang"
  module ietf-ipfix-psamp {
    namespace "urn:ietf:params:xml:ns:yang:ietf-ipfix-psamp";
    prefix ipfix;

    import ietf-yang-types { prefix yang; }
    import ietf-inet-types { prefix inet; }

    organization
      "IETF IPFIX Working Group";

    contact
      "WG Web:  <http://tools.ietf.org/wg/ipfix/>
      WG List:  <ipfix@ietf.org>

      WG Chair: Nevil Brownlee
                <n.brownlee@auckland.ac.nz>

      WG Chair: Juergen Quittek
                <quittek@neclab.eu>

      Editor:   Gerhard Muenz
                <muenz@net.in.tum.de>";

    description
      "IPFIX/PSAMP Configuration Data Model

      Copyright (c) 2012 IETF Trust and the persons identified as
      the document authors.  All rights reserved.
      Redistribution and use in source and binary forms, with or
      without modification, is permitted pursuant to, and subject
      to the license terms contained in, the Simplified BSD License
      set forth in Section 4.c of the IETF Trust's Legal Provisions
      Relating to IETF Documents
      (http://trustee.ietf.org/license-info).";

    revision 2012-09-05 {
      description "Initial version";
      reference "RFC 6728: Configuration Data Model for the IP Flow
        Information Export (IPFIX) and Packet Sampling (PSAMP)
        Protocols";
    }

    /*****************************************************************
    * Features
    *****************************************************************/

    feature exporter {
      description "If supported, the Monitoring Device can be used as
        an Exporter.  Exporting Processes can be configured.";
    }

    feature collector {
      description "If supported, the Monitoring Device can be used as
        a Collector.  Collecting Processes can be configured.";
    }

    feature meter {
      description "If supported, Observation Points, Selection
        Processes, and Caches can be configured.";
    }

    feature psampSampCountBased {
      description "If supported, the Monitoring Device supports
        count-based Sampling.  The Selector method sampCountBased can
        be configured.";

    }

    feature psampSampTimeBased {
      description "If supported, the Monitoring Device supports
        time-based Sampling.  The Selector method sampTimeBased can
        be configured.";
    }

    feature psampSampRandOutOfN {
      description "If supported, the Monitoring Device supports
        random n-out-of-N Sampling.  The Selector method
        sampRandOutOfN can be configured.";
    }

    feature psampSampUniProb {
      description "If supported, the Monitoring Device supports
        uniform probabilistic Sampling.  The Selector method
        sampUniProb can be configured.";
    }

    feature psampFilterMatch {
      description "If supported, the Monitoring Device supports
        property match Filtering.  The Selector method filterMatch
        can be configured.";
    }

    feature psampFilterHash {
      description "If supported, the Monitoring Device supports
        hash-based Filtering.  The Selector method filterHash can be
        configured.";
    }

    feature immediateCache {
      description "If supported, the Monitoring Device supports
        Caches generating PSAMP Packet Reports by configuration with
        immediateCache.";
    }

    feature timeoutCache {
      description "If supported, the Monitoring Device supports
        Caches generating IPFIX Flow Records by configuration with
        timeoutCache.";
    }

    feature naturalCache {
      description "If supported, the Monitoring Device supports
        Caches generating IPFIX Flow Records by configuration with
        naturalCache.";

    }

    feature permanentCache {
      description "If supported, the Monitoring Device supports
        Caches generating IPFIX Flow Records by configuration with
        permanentCache.";
    }

    feature udpTransport {
      description "If supported, the Monitoring Device supports UDP
        as the transport protocol.";
    }

    feature tcpTransport {
      description "If supported, the Monitoring Device supports TCP
        as the transport protocol.";
    }

    feature fileReader {
      description "If supported, the Monitoring Device supports the
        configuration of Collecting Processes as File Readers.";
    }

    feature fileWriter {
      description "If supported, the Monitoring Device supports the
        configuration of Exporting Processes as File Writers.";
    }

    /*****************************************************************
    * Identities
    *****************************************************************/

    /*** Hash function identities ***/
    identity hashFunction {
      description "Base identity for all hash functions used for
        hash-based packet Filtering.  Identities derived from
        this base are used by the leaf
        /ipfix/selectionProcess/selector/filterHash/hashFunction.";
    }
    identity BOB {
      base "hashFunction";
      description "BOB hash function";
      reference "RFC 5475, Section 6.2.4.1.";
    }
    identity IPSX {
      base "hashFunction";
      description "IPSX hash function";
      reference "RFC 5475, Section 6.2.4.1.";

    }
    identity CRC {
      base "hashFunction";
      description "CRC hash function";
      reference "RFC 5475, Section 6.2.4.1.";
    }

    /*** Export mode identities ***/
    identity exportMode {
      description "Base identity for different usages of export
        destinations configured for an Exporting Process.
        Identities derived from this base are used by the leaf
        /ipfix/exportingProcess/exportMode.";
    }
    identity parallel {
      base "exportMode";
      description "Parallel export of Data Records to all
        destinations configured for the Exporting Process.";
    }
    identity loadBalancing {
      base "exportMode";
      description "Load-balancing between the different destinations
        configured for the Exporting Process.";
    }
    identity fallback {
      base "exportMode";
      description "Export to the primary destination (i.e., the first
        SCTP, UDP, TCP, or file destination configured for the
        Exporting Process).  If the export to the primary destination
        fails, the Exporting Process tries to export to the secondary
        destination.  If the secondary destination fails as well, it
        continues with the tertiary, etc.";
    }

    /*** Options type identities ***/
    identity optionsType {
      description "Base identity for report types exported with
        options.  Identities derived from this base are used by the leaf
        /ipfix/exportingProcess/options/optionsType.";
    }
    identity meteringStatistics {
      base "optionsType";
      description "Metering Process Statistics.";
      reference "RFC 5101, Section 4.1.";
    }
    identity meteringReliability {
      base "optionsType";
      description "Metering Process Reliability Statistics.";

      reference "RFC 5101, Section 4.2.";
    }
    identity exportingReliability {
      base "optionsType";
      description "Exporting Process Reliability
        Statistics.";
      reference "RFC 5101, Section 4.3.";
    }
    identity flowKeys {
      base "optionsType";
      description "Flow Keys.";
      reference "RFC 5101, Section 4.4.";
    }
    identity selectionSequence {
      base "optionsType";
      description "Selection Sequence and Selector Reports.";
      reference "RFC 5476, Sections 6.5.1 and 6.5.2.";
    }
    identity selectionStatistics {
      base "optionsType";
      description "Selection Sequence Statistics Report.";
      reference "RFC 5476, Sections 6.5.3.";
    }
    identity accuracy {
      base "optionsType";
      description "Accuracy Report.";
      reference "RFC 5476, Section 6.5.4.";
    }
    identity reducingRedundancy {
      base "optionsType";
      description "Enables the utilization of Options Templates to
        reduce redundancy in the exported Data Records.";
      reference "RFC 5473.";
    }
    identity extendedTypeInformation {
      base "optionsType";
      description "Export of extended type information for
        enterprise-specific Information Elements used in the
        exported Templates.";
      reference "RFC 5610.";
    }

    /*****************************************************************
    * Type definitions
    *****************************************************************/

    typedef ieNameType {
      type string {

        length "1..max";
        pattern "\S+";
      }
      description "Type for Information Element names.  Whitespaces
        are not allowed.";
    }

    typedef ieIdType {
      type uint16 {
        range "1..32767" {
          description "Valid range of Information Element
              identifiers.";
          reference "RFC 5102, Section 4.";
        }
      }
      description "Type for Information Element identifiers.";
    }

    typedef nameType {
      type string {
        length "1..max";
        pattern "\S(.*\S)?";
      }
      description "Type for 'name' leafs, which are used to identify
        specific instances within lists, etc.
        Leading and trailing whitespaces are not allowed.";
    }

    typedef ifNameType {
      type string {
        length "1..255";
      }
      description "This corresponds to the DisplayString textual
        convention of SNMPv2-TC, which is used for ifName in the IF
        MIB module.";
      reference "RFC 2863 (ifName).";
    }

    typedef direction {
      type enumeration {
        enum ingress {
          description "This value is used for monitoring incoming
            packets.";
        }
        enum egress {
          description "This value is used for monitoring outgoing
            packets.";
        }

        enum both {
          description "This value is used for monitoring incoming and
            outgoing packets.";
        }
      }
      description "Direction of packets going through an interface or
        linecard.";
    }

    typedef transportSessionStatus {
      type enumeration {
        enum inactive {
          description "This value MUST be used for Transport Sessions
            that are specified in the system but currently not active.
            The value can be used for Transport Sessions that are
            backup (secondary) sessions.";
        }
        enum active {
          description "This value MUST be used for Transport Sessions
            that are currently active and transmitting or receiving
            data.";
        }
        enum unknown {
          description "This value MUST be used if the status of the
            Transport Sessions cannot be detected by the device.  This
            value should be avoided as far as possible.";
        }
      }
      description "Status of a Transport Session.";
      reference "RFC 6615, Section 8 (ipfixTransportSessionStatus).";
    }

    /*****************************************************************
    * Groupings
    *****************************************************************/

    grouping observationPointParameters {
      description "Interface as input to Observation Point.";
      leaf observationPointId {
        type uint32;
        config false;
        description "Observation Point ID (i.e., the value of the
          Information Element observationPointId) assigned by the
          Monitoring Device.";
        reference "IANA registry for IPFIX Entities,
          http://www.iana.org/assignments/ipfix.";
      }
      leaf observationDomainId {

        type uint32;
        mandatory true;
        description "The Observation Domain ID associates the
          Observation Point to an Observation Domain.  Observation
          Points with identical Observation Domain IDs belong to the
          same Observation Domain.
          Note that this parameter corresponds to
          ipfixObservationPointObservationDomainId in the IPFIX MIB
          module.";
        reference "RFC 5101; RFC 6615, Section 8
          (ipfixObservationPointObservationDomainId).";
      }
      leaf-list ifName {
        type ifNameType;
        description "List of names identifying interfaces of the
          Monitoring Device.  The Observation Point observes packets at
          the specified interfaces.";
      }
      leaf-list ifIndex {
        type uint32;
        description "List of ifIndex values pointing to entries in the
          ifTable of the IF-MIB module maintained by the Monitoring
          Device.  The Observation Point observes packets at the
          specified interfaces.
          This parameter SHOULD only be used if an SNMP agent enables
          access to the ifTable.
          Note that this parameter corresponds to
          ipfixObservationPointPhysicalInterface in the IPFIX MIB
          module.";
        reference "RFC 2863; RFC 6615, Section 8
          (ipfixObservationPointPhysicalInterface).";
      }
      leaf-list entPhysicalName {
        type string;
        description "List of names identifying physical entities of the
          Monitoring Device.  The Observation Point observes packets at
          the specified entities.";
      }
      leaf-list entPhysicalIndex {
        type uint32;
        description "List of entPhysicalIndex values pointing to
          entries in the entPhysicalTable of the ENTITY-MIB module
          maintained by the Monitoring Device.  The Observation Point
          observes packets at the specified entities.
          This parameter SHOULD only be used if an SNMP agent enables
          access to the entPhysicalTable.
          Note that this parameter corresponds to
          ipfixObservationPointPhysicalEntity in the IPFIX MIB

          module.";
        reference "RFC 4133; RFC 6615, Section 8
          (ipfixObservationPointPhysicalInterface).";
      }
      leaf direction {
        type direction;
        default both;
        description "Direction of packets.  If not applicable (e.g., in
          the case of a sniffing interface in promiscuous mode), this
          parameter is ignored.";
      }
    }

    grouping sampCountBasedParameters {
      description "Configuration parameters of a Selector applying
        systematic count-based packet Sampling to the packet
        stream.";
      reference "RFC 5475, Section 5.1; RFC 5476, Section 6.5.2.1.";
      leaf packetInterval {
        type uint32;
        units packets;
        mandatory true;
        description "The number of packets that are consecutively
          sampled between gaps of length packetSpace.
          This parameter corresponds to the Information Element
          samplingPacketInterval and to psampSampCountBasedInterval
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.2.2; RFC 6727, Section 6
          (psampSampCountBasedInterval).";
      }
      leaf packetSpace {
        type uint32;
        units packets;
        mandatory true;
        description "The number of unsampled packets between two
          Sampling intervals.
          This parameter corresponds to the Information Element
          samplingPacketSpace and to psampSampCountBasedSpace
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.2.3; RFC 6727, Section 6
          (psampSampCountBasedSpace).";
      }
    }

    grouping sampTimeBasedParameters {
      description "Configuration parameters of a Selector applying
        systematic time-based packet Sampling to the packet
        stream.";

      reference "RFC 5475, Section 5.1; RFC 5476, Section 6.5.2.2.";
      leaf timeInterval {
        type uint32;
        units microseconds;
        mandatory true;
        description "The time interval in microseconds during
          which all arriving packets are sampled between gaps
          of length timeSpace.
          This parameter corresponds to the Information Element
          samplingTimeInterval and to psampSampTimeBasedInterval
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.2.4; RFC 6727, Section 6
          (psampSampTimeBasedInterval).";
      }
      leaf timeSpace {
        type uint32;
        units microseconds;
        mandatory true;
        description "The time interval in microseconds during
          which no packets are sampled between two Sampling
          intervals specified by timeInterval.
          This parameter corresponds to the Information Element
          samplingTimeInterval and to psampSampTimeBasedSpace
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.2.5; RFC 6727, Section 6
          (psampSampTimeBasedSpace).";
      }
    }

    grouping sampRandOutOfNParameters {
      description "Configuration parameters of a Selector applying
        n-out-of-N packet Sampling to the packet stream.";
      reference "RFC 5475, Section 5.2.1; RFC 5476, Section 6.5.2.3.";
      leaf size {
        type uint32;
        units packets;
        mandatory true;
        description "The number of elements taken from the parent
          population.
          This parameter corresponds to the Information Element
          samplingSize and to psampSampRandOutOfNSize in the PSAMP
          MIB module.";
        reference "RFC 5477, Section 8.2.6; RFC 6727, Section 6
          (psampSampRandOutOfNSize).";
      }
      leaf population {
        type uint32;
        units packets;

        mandatory true;
        description "The number of elements in the parent
          population.
          This parameter corresponds to the Information Element
          samplingPopulation and to psampSampRandOutOfNPopulation
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.2.7; RFC 6727, Section 6
          (psampSampRandOutOfNPopulation).";
      }
    }

    grouping sampUniProbParameters {
      description "Configuration parameters of a Selector applying
        uniform probabilistic packet Sampling (with equal
        probability per packet) to the packet stream.";
      reference "RFC 5475, Section 5.2.2.1;
        RFC 5476, Section 6.5.2.4.";
      leaf probability {
        type decimal64 {
          fraction-digits 18;
          range "0..1";
        }
        mandatory true;
        description "Probability that a packet is sampled,
          expressed as a value between 0 and 1.  The probability
          is equal for every packet.
          This parameter corresponds to the Information Element
          samplingProbability and to psampSampUniProbProbability
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.2.8; RFC 6727, Section 6
          (psampSampUniProbProbability).";
      }
    }

    grouping filterMatchParameters {
      description "Configuration parameters of a Selector applying
        property match Filtering to the packet stream.
        The field to be matched is specified as an Information
        Element.";
      reference "RFC 5475, Section 6.1; RFC 5476, Section 6.5.2.5.";
      choice nameOrId {
        mandatory true;
        description "The field to be matched is specified by
          either the name or the identifier of the Information
          Element.";
        leaf ieName {
          type ieNameType;
          description "Name of the Information Element.";

        }
        leaf ieId {
          type ieIdType;
          description "Identifier of the Information Element.";
        }
      }
      leaf ieEnterpriseNumber {
        type uint32;
        default 0;
        description "If this parameter is zero, the Information
          Element is registered in the IANA registry of IPFIX
          Information Elements.
          If this parameter is configured with a non-zero private
          enterprise number, the Information Element is
          enterprise-specific.";
        reference "IANA registry for Private Enterprise Numbers,
          http://www.iana.org/assignments/enterprise-numbers;
          IANA registry for IPFIX Entities,
          http://www.iana.org/assignments/ipfix.";
      }
      leaf value {
        type string;
        mandatory true;
        description "Matching value of the Information Element.";
      }
    }

    grouping filterHashParameters {
      description "Configuration parameters of a Selector applying
        hash-based Filtering to the packet stream.";
      reference "RFC 5475, Section 6.2; RFC 5476, Section 6.5.2.6.";
      leaf hashFunction {
        type identityref {
          base "hashFunction";
        }
        default BOB;
        description "Hash function to be applied.  According to
          RFC 5475, Section 6.2.4.1, 'BOB' must be used in order to
          be compliant with PSAMP.
          This parameter functionally corresponds to
          psampFiltHashFunction in the PSAMP MIB module.";
        reference "RFC 6727, Section 6 (psampFiltHashFunction)";
      }
      leaf initializerValue {
        type uint64;
        description "Initializer value to the hash function.
          If not configured by the user, the Monitoring Device
          arbitrarily chooses an initializer value.

          This parameter corresponds to the Information Element
          hashInitialiserValue and to psampFiltHashInitializerValue
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.3.9; RFC 6727, Section 6
          (psampFiltHashInitializerValue).";
      }
      leaf ipPayloadOffset {
        type uint64;
        units octets;
        default 0;
        description "IP payload offset indicating the position of
          the first payload byte considered as input to the hash
          function.
          Default value 0 corresponds to the minimum offset that
          must be configurable according to RFC 5476, Section
          6.5.2.6.
          This parameter corresponds to the Information Element
          hashIPPayloadOffset and to psampFiltHashIpPayloadOffset
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.3.2; RFC 6727, Section 6
          (psampFiltHashIpPayloadOffset).";
      }
      leaf ipPayloadSize {
        type uint64;
        units octets;
        default 8;
        description "Number of IP payload bytes used as input to
          the hash function, counted from the payload offset.
          If the IP payload is shorter than the payload range,
          all available payload octets are used as input.
          Default value 8 corresponds to the minimum IP payload
          size that must be configurable according to RFC 5476,
          Section 6.5.2.6.
          This parameter corresponds to the Information Element
          hashIPPayloadSize and to psampFiltHashIpPayloadSize
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.3.3; RFC 6727, Section 6
          (psampFiltHashIpPayloadSize).";
      }
      leaf digestOutput {
        type boolean;
        default false;
        description "If true, the output from this Selector is
          included in the Packet Report as a packet digest.
          Therefore, the configured Cache Layout needs to contain
          a digestHashValue field.
          This parameter corresponds to the Information Element
          hashDigestOutput.";

        reference "RFC 5477, Section 8.3.8.";
      }
      leaf outputRangeMin {
        type uint64;
        config false;
        description "Beginning of the hash function's potential
          range.
          This parameter corresponds to the Information Element
          hashOutputRangeMin and to psampFiltHashOutputRangeMin
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.3.4; RFC 6727, Section 6
          (psampFiltHashOutputRangeMin).";
      }
      leaf outputRangeMax {
        type uint64;
        config false;
        description "End of the hash function's potential range.
          This parameter corresponds to the Information Element
          hashOutputRangeMax and to psampFiltHashOutputRangeMax
          in the PSAMP MIB module.";
        reference "RFC 5477, Section 8.3.5; RFC 6727, Section 6
          (psampFiltHashOutputRangeMax).";
      }
      list selectedRange {
        key name;
        min-elements 1;
        description "List of hash function return ranges for
          which packets are selected.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        leaf min {
          type uint64;
          description "Beginning of the hash function's selected
            range.
            This parameter corresponds to the Information Element
            hashSelectedRangeMin and to psampFiltHashSelectedRangeMin
            in the PSAMP MIB module.";
          reference "RFC 5477, Section 8.3.6; RFC 6727, Section 6
          (psampFiltHashSelectedRangeMin).";
        }
        leaf max {
          type uint64;
          description "End of the hash function's selected range.
            This parameter corresponds to the Information Element
            hashSelectedRangeMax and to psampFiltHashSelectedRangeMax
            in the PSAMP MIB module.";

          reference "RFC 5477, Section 8.3.7; RFC 6727, Section 6
          (psampFiltHashSelectedRangeMax).";
        }
      }
    }

    grouping selectorParameters {
      description "Configuration and state parameters of a Selector.";
      choice Method {
        mandatory true;
        description "Packet selection method applied by the Selector.";
        leaf selectAll {
          type empty;
          description "Method that selects all packets.";
        }
        container sampCountBased {
          if-feature psampSampCountBased;
          description "Systematic count-based packet Sampling.";
          uses sampCountBasedParameters;
        }
        container sampTimeBased {
          if-feature psampSampTimeBased;
          description "Systematic time-based packet Sampling.";
          uses sampTimeBasedParameters;
        }
        container sampRandOutOfN {
          if-feature psampSampRandOutOfN;
          description "n-out-of-N packet Sampling.";
          uses sampRandOutOfNParameters;
        }
        container sampUniProb {
          if-feature psampSampUniProb;
          description "Uniform probabilistic packet Sampling.";
          uses sampUniProbParameters;
        }
        container filterMatch {
          if-feature psampFilterMatch;
          description "Property match Filtering.";
          uses filterMatchParameters;
        }
        container filterHash {
          if-feature psampFilterHash;
          description "Hash-based Filtering.";
          uses filterHashParameters;
        }
      }
      leaf packetsObserved {
        type yang:counter64;

        config false;
        description "The number of packets observed at the input of
          the Selector.
          If this is the first Selector in the Selection Process,
          this counter corresponds to the total number of packets in
          all Observed Packet Streams at the input of the Selection
          Process.  Otherwise, the counter corresponds to the total
          number of packets at the output of the preceding Selector.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          selectorDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixSelectorStatsPacketsObserved in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixSelectorStatsPacketsObserved).";
      }
      leaf packetsDropped {
        type yang:counter64;
        config false;
        description "The total number of packets discarded by the
          Selector.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          selectorDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixSelectorStatsPacketsDropped in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixSelectorStatsPacketsDropped).";
      }
      leaf selectorDiscontinuityTime {
        type yang:date-and-time;
        config false;
        description "Timestamp of the most recent occasion at which
          one or more of the Selector counters suffered a
          discontinuity.
          Note that this parameter functionally corresponds to
          ipfixSelectionProcessStatsDiscontinuityTime in the IPFIX
          MIB module.  In contrast to
          ipfixSelectionProcessStatsDiscontinuityTime, the time is
          absolute and not relative to sysUpTime.";
        reference "RFC 6615, Section 8
          (ipfixSelectionProcessStatsDiscontinuityTime).";
      }
    }

    grouping cacheLayoutParameters {
      description "Cache Layout parameters used by immediateCache,
        timeoutCache, naturalCache, and permanentCache.";
      container cacheLayout {
        description "Cache Layout parameters.";
        list cacheField {
          key name;
          min-elements 1;
          description "Superset of fields that are included in the
            Packet Reports or Flow Records generated by the Cache.";
          leaf name {
            type nameType;
            description "Key of this list.";
          }
          choice nameOrId {
            mandatory true;
            description "Name or identifier of the Information
              Element.";
            reference "RFC 5102, Section 2; IANA registry for IPFIX
              Entities, http://www.iana.org/assignments/ipfix.";
            leaf ieName {
              type ieNameType;
              description "Name of the Information Element.";
            }
            leaf ieId {
              type ieIdType;
              description "Identifier of the Information Element.";
            }
          }
          leaf ieLength {
            type uint16;
            units octets;
            description "Length of the field in which the Information
              Element is encoded.  A value of 65535 specifies a
              variable-length Information Element.  For Information
              Elements of integer and float type, the field length MAY
              be set to a smaller value than the standard length of
              the abstract data type if the rules of reduced size
              encoding are fulfilled.
              If not configured by the user, this parameter is set by
              the Monitoring Device.";
            reference "RFC 5101, Section 6.2.";
          }
          leaf ieEnterpriseNumber {
            type uint32;
            default 0;
            description "If this parameter is zero, the Information
              Element is registered in the IANA registry of IPFIX

              Information Elements.
              If this parameter is configured with a non-zero private
              enterprise number, the Information Element is
              enterprise-specific.
              If the enterprise number is set to 29305, this field
              contains a Reverse Information Element.  In this case,
              the Cache MUST generate Data Records in accordance to
              RFC 5103.";
            reference "RFC 5101; RFC 5103;
              IANA registry for Private Enterprise Numbers,
              http://www.iana.org/assignments/enterprise-numbers;
              IANA registry for IPFIX Entities,
              http://www.iana.org/assignments/ipfix.";
          }
          leaf isFlowKey {
            when "(name(../../..) != 'immediateCache')
              and
              ((count(../ieEnterpriseNumber) = 0)
              or
              (../ieEnterpriseNumber != 29305))" {
              description "This parameter is not available for
                Reverse Information Elements (which have enterprise
                number 29305).  It is also not available for
                immediateCache.";
            }
            type empty;
            description "If present, this is a flow key.";
          }
        }
      }
    }

    grouping flowCacheParameters {
      description "Configuration and state parameters of a Cache
        generating Flow Records.";
      leaf maxFlows {
        type uint32;
        units flows;
        description "This parameter configures the maximum number of
          Flows in the Cache, which is the maximum number of Flows
          that can be measured simultaneously.
          The Monitoring Device MUST ensure that sufficient resources
          are available to store the configured maximum number of
          Flows.
          If the maximum number of Flows is measured, an additional
          Flow can be measured only if an existing entry is removed.
          However, traffic that pertains to existing Flows can
          continue to be measured.";

      }
      leaf activeTimeout {
        when "(name(..) = 'timeoutCache') or
          (name(..) = 'naturalCache')" {
          description "This parameter is only available for
            timeoutCache and naturalCache.";
        }
        type uint32;
        units seconds;
        description "This parameter configures the time in
          seconds after which a Flow is expired even though packets
          matching this Flow are still received by the Cache.
          The parameter value zero indicates infinity, meaning that
          there is no active timeout.
          If not configured by the user, the Monitoring Device sets
          this parameter.
          Note that this parameter corresponds to
          ipfixMeteringProcessCacheActiveTimeout in the IPFIX
          MIB module.";
        reference "RFC 6615, Section 8
          (ipfixMeteringProcessCacheActiveTimeout).";
      }
      leaf idleTimeout {
        when "(name(..) = 'timeoutCache') or
          (name(..) = 'naturalCache')" {
          description "This parameter is only available for
            timeoutCache and naturalCache.";
        }
        type uint32;
        units seconds;
        description "This parameter configures the time in
          seconds after which a Flow is expired if no more packets
          matching this Flow are received by the Cache.
          The parameter value zero indicates infinity, meaning that
          there is no idle timeout.
          If not configured by the user, the Monitoring Device sets
          this parameter.
          Note that this parameter corresponds to
          ipfixMeteringProcessCacheIdleTimeout in the IPFIX
          MIB module.";
        reference "RFC 6615, Section 8
          (ipfixMeteringProcessCacheIdleTimeout).";
      }
      leaf exportInterval {
        when "name(..) = 'permanentCache'" {
          description "This parameter is only available for
            permanentCache.";
        }

        type uint32;
        units seconds;
        description "This parameter configures the interval (in
          seconds) for periodical export of Flow Records.
          If not configured by the user, the Monitoring Device sets
          this parameter.";
      }
      leaf activeFlows {
        type yang:gauge32;
        units flows;
        config false;
        description "The number of Flows currently active in this
          Cache.
          Note that this parameter corresponds to
          ipfixMeteringProcessCacheActiveFlows in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixMeteringProcessCacheActiveFlows).";
      }
      leaf unusedCacheEntries {
        type yang:gauge32;
        units flows;
        config false;
        description "The number of unused Cache entries in this
          Cache.
          Note that this parameter corresponds to
          ipfixMeteringProcessCacheUnusedCacheEntries in the IPFIX
          MIB module.";
        reference "RFC 6615, Section 8
          (ipfixMeteringProcessCacheUnusedCacheEntries).";
      }
    }

    grouping exportingProcessParameters {
      description "Parameters of an Exporting Process.";
      leaf exportingProcessId {
        type uint32;
        config false;
        description "The identifier of the Exporting Process.
          This parameter corresponds to the Information Element
          exportingProcessId.  Its occurrence helps to associate
          Exporting Process parameters with Exporing Process
          statistics exported by the Monitoring Device using the
          Exporting Process Reliability Statistics Template as
          defined by the IPFIX protocol specification.";
        reference "RFC 5101, Section 4.3; IANA registry for IPFIX
          Entities, http://www.iana.org/assignments/ipfix.";
      }

      leaf exportMode {
        type identityref {
          base "exportMode";
        }
        default parallel;
        description "This parameter determines to which configured
          destination(s) the incoming Data Records are exported.";
      }
      list destination {
        key name;
        min-elements 1;
        description "List of export destinations.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        choice DestinationParameters {
          mandatory true;
          description "Configuration parameters depend on whether
            SCTP, UDP, or TCP is used as transport protocol, and
            whether the destination is a file.";
          container sctpExporter {
            description "SCTP parameters.";
            uses sctpExporterParameters;
          }
          container udpExporter {
            if-feature udpTransport;
            description "UDP parameters.";
            uses udpExporterParameters;
          }
          container tcpExporter {
            if-feature tcpTransport;
            description "TCP parameters.";
            uses tcpExporterParameters;
          }
          container fileWriter {
            if-feature fileWriter;
            description "File Writer parameters.";
            uses fileWriterParameters;
          }
        }
      }
      list options {
        key name;
        description "List of options reported by the Exporting
          Process.";
        leaf name {
          type nameType;

          description "Key of this list.";
        }
        uses optionsParameters;
      }
    }

    grouping commonExporterParameters {
      description "Parameters of en export destination that are
        common to all transport protocols.";
      leaf ipfixVersion {
        type uint16;
        default 10;
        description "IPFIX version number.";
        reference "RFC 5101.";
      }
      leaf destinationPort {
        type inet:port-number;
        description "If not configured by the user, the Monitoring
          Device uses the default port number for IPFIX, which is
          4739 without TLS or DTLS and 4740 if TLS or DTLS is
          activated.";
      }
      choice indexOrName {
        description "Index or name of the interface as stored in the
          ifTable of IF-MIB.
          If configured, the Exporting Process MUST use the given
          interface to export IPFIX Messages to the export
          destination.
          If omitted, the Exporting Process selects the outgoing
          interface based on local routing decision and accepts
          return traffic, such as transport-layer acknowledgments,
          on all available interfaces.";
        reference "RFC 2863.";
        leaf ifIndex {
          type uint32;
          description "Index of an interface as stored in the ifTable
            of IF-MIB.";
          reference "RFC 2863.";
        }
        leaf ifName {
          type string;
          description "Name of an interface as stored in the ifTable
            of IF-MIB.";
          reference "RFC 2863.";
        }
      }
      leaf sendBufferSize {
        type uint32;

        units bytes;
        description "Size of the socket send buffer.
          If not configured by the user, this parameter is set by
          the Monitoring Device.";
      }
      leaf rateLimit {
        type uint32;
        units "bytes per second";
        description "Maximum number of bytes per second the Exporting
          Process may export to the given destination.  The number of
          bytes is calculated from the lengths of the IPFIX Messages
          exported.  If not configured, no rate limiting is performed.";
        reference "RFC 5476, Section 6.3.";
      }
      container transportLayerSecurity {
        presence "If transportLayerSecurity is present, DTLS is
          enabled if the transport protocol is SCTP or UDP, and TLS
          is enabled if the transport protocol is TCP.";
        description "TLS or DTLS configuration.";
        uses transportLayerSecurityParameters;
      }
      container transportSession {
        config false;
        description "State parameters of the Transport Session
          directed to the given destination.";
        uses transportSessionParameters;
      }
    }

    grouping sctpExporterParameters {
      description "SCTP-specific export destination parameters.";
      uses commonExporterParameters;
      leaf-list sourceIPAddress {
        type inet:ip-address;
        description "List of source IP addresses used by the
          Exporting Process.
          If configured, the specified addresses are eligible local
          IP addresses of the multihomed SCTP endpoint.
          If not configured, all locally assigned IP addresses are
          eligible local IP addresses.";
        reference "RFC 4960, Section 6.4.";
      }
      leaf-list destinationIPAddress {
        type inet:ip-address;
        min-elements 1;
        description "One or more IP addresses of the Collecting
          Process to which IPFIX Messages are sent.
          The user MUST ensure that all configured IP addresses

          belong to the same Collecting Process.
          The Exporting Process tries to establish an SCTP
          association to any of the configured destination IP
          addresses.";
        reference "RFC 4960, Section 6.4.";
      }
      leaf timedReliability {
        type uint32;
        units milliseconds;
        default 0;
        description "Lifetime in milliseconds until an IPFIX
          Message containing Data Sets only is 'abandoned' due to
          the timed reliability mechanism of PR-SCTP.
          If this parameter is set to zero, reliable SCTP
          transport is used for all Data Records.
          Regardless of the value of this parameter, the Exporting
          Process MAY use reliable SCTP transport for Data Sets
          associated with Options Templates.";
        reference "RFC 3758; RFC 4960.";
      }
    }

    grouping udpExporterParameters {
      description "Parameters of a UDP export destination.";
      uses commonExporterParameters;
      leaf sourceIPAddress {
        type inet:ip-address;
        description "Source IP address used by the Exporting Process.
        If not configured, the IP address assigned to the outgoing
        interface is used as source IP address.";
      }
      leaf destinationIPAddress {
        type inet:ip-address;
        mandatory true;
        description "IP address of the Collection Process to which
          IPFIX Messages are sent.";
      }
      leaf maxPacketSize {
        type uint16;
        units octets;
        description "This parameter specifies the maximum size of
          IP packets sent to the Collector.  If set to zero, the
          Exporting Device MUST derive the maximum packet size
          from path MTU discovery mechanisms.
          If not configured by the user, this parameter is set by
          the Monitoring Device.";
      }
      leaf templateRefreshTimeout {

        type uint32;
        units seconds;
        default 600;
        description "Sets time after which Templates are resent in the
          UDP Transport Session.
          Note that the configured lifetime MUST be adapted to the
          templateLifeTime parameter value at the receiving Collecting
          Process.
          Note that this parameter corresponds to
          ipfixTransportSessionTemplateRefreshTimeout in the IPFIX
          MIB module.";
        reference "RFC 5101, Section 10.3.6; RFC 6615, Section 8
          (ipfixTransportSessionTemplateRefreshTimeout).";
      }
      leaf optionsTemplateRefreshTimeout {
        type uint32;
        units seconds;
        default 600;
        description "Sets time after which Options Templates are
          resent in the UDP Transport Session.
          Note that the configured lifetime MUST be adapted to the
          optionsTemplateLifeTime parameter value at the receiving
          Collecting Process.
          Note that this parameter corresponds to
          ipfixTransportSessionOptionsTemplateRefreshTimeout in the
          IPFIX MIB module.";
        reference "RFC 5101, Section 10.3.6; RFC 6615, Section 8
          (ipfixTransportSessionOptionsTemplateRefreshTimeout).";
      }
      leaf templateRefreshPacket {
        type uint32;
        units "IPFIX Messages";
        description "Sets number of IPFIX Messages after which
          Templates are resent in the UDP Transport Session.
          Note that this parameter corresponds to
          ipfixTransportSessionTemplateRefreshPacket in the IPFIX
          MIB module.
          If omitted, Templates are only resent after timeout.";
        reference "RFC 5101, Section 10.3.6; RFC 6615, Section 8
          (ipfixTransportSessionTemplateRefreshPacket).";
      }
      leaf optionsTemplateRefreshPacket {
        type uint32;
        units "IPFIX Messages";
        description "Sets number of IPFIX Messages after which
          Options Templates are resent in the UDP Transport Session
          protocol.
          Note that this parameter corresponds to

          ipfixTransportSessionOptionsTemplateRefreshPacket in the
          IPFIX MIB module.
          If omitted, Templates are only resent after timeout.";
        reference "RFC 5101, Section 10.3.6; RFC 6615, Section 8
          (ipfixTransportSessionOptionsTemplateRefreshPacket).";
      }
    }

    grouping tcpExporterParameters {
      description "Parameters of a TCP export destination.";
      uses commonExporterParameters;
      leaf sourceIPAddress {
        type inet:ip-address;
        description "Source IP address used by the Exporting Process.
          If not configured by the user, this parameter is set by
          the Monitoring Device to an IP address assigned to the
          outgoing interface.";
      }
      leaf destinationIPAddress {
        type inet:ip-address;
        mandatory true;
        description "IP address of the Collection Process to which
          IPFIX Messages are sent.";
      }
    }

    grouping fileWriterParameters {
      description "File Writer parameters.";
      leaf ipfixVersion {
        type uint16;
        default 10;
        description "IPFIX version number.";
        reference "RFC 5101.";
      }
      leaf file {
        type inet:uri;
        mandatory true;
        description "URI specifying the location of the file.";
      }
      leaf bytes {
        type yang:counter64;
        units octets;
        config false;
        description "The number of bytes written by the File Writer.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileWriterDiscontinuityTime.";

      }
      leaf messages {
        type yang:counter64;
        units "IPFIX Messages";
        config false;
        description "The number of IPFIX Messages written by the File
          Writer.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileWriterDiscontinuityTime.";
      }
      leaf discardedMessages {
        type yang:counter64;
        units "IPFIX Messages";
        config false;
        description "The number of IPFIX Messages that could not be
          written by the File Writer due to internal buffer
          overflows, limited storage capacity, etc.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileWriterDiscontinuityTime.";
      }
      leaf records {
        type yang:counter64;
        units "Data Records";
        config false;
        description "The number of Data Records written by the File
          Writer.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileWriterDiscontinuityTime.";
      }
      leaf templates {
        type yang:counter32;
        units "Templates";
        config false;
        description "The number of Template Records (excluding
          Options Template Records) written by the File Writer.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileWriterDiscontinuityTime.";
      }
      leaf optionsTemplates {
        type yang:counter32;

        units "Options Templates";
        config false;
        description "The number of Options Template Records written
          by the File Writer.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileWriterDiscontinuityTime.";
      }
      leaf fileWriterDiscontinuityTime {
        type yang:date-and-time;
        config false;
        description "Timestamp of the most recent occasion at which
          one or more File Writer counters suffered a discontinuity.
          In contrast to discontinuity times in the IPFIX MIB module,
          the time is absolute and not relative to sysUpTime.";
      }
      list template {
        config false;
        description "This list contains the Templates and Options
          Templates that have been written by the File Reader.
          Withdrawn or invalidated (Options) Templates MUST be removed
          from this list.";
        uses templateParameters;
      }
    }

    grouping optionsParameters {
      description "Parameters specifying the data export using an
        Options Template.";
      leaf optionsType {
        type identityref {
          base "optionsType";
        }
        mandatory true;
        description "Type of the exported options data.";
      }
      leaf optionsTimeout {
        type uint32;
        units milliseconds;
        description "Time interval for periodic export of the options
          data.  If set to zero, the export is triggered when the
          options data has changed.
          If not configured by the user, this parameter is set by the
          Monitoring Device.";
      }
    }

    grouping collectingProcessParameters {
      description "Parameters of a Collecting Process.";
      list sctpCollector {
        key name;
        description "List of SCTP receivers (sockets) on which the
          Collecting Process receives IPFIX Messages.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        uses sctpCollectorParameters;
      }
      list udpCollector {
        if-feature udpTransport;
        key name;
        description "List of UDP receivers (sockets) on which the
          Collecting Process receives IPFIX Messages.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        uses udpCollectorParameters;
      }
      list tcpCollector {
        if-feature tcpTransport;
        key name;
        description "List of TCP receivers (sockets) on which the
          Collecting Process receives IPFIX Messages.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        uses tcpCollectorParameters;
      }
      list fileReader {
        if-feature fileReader;
        key name;
        description "List of File Readers from which the Collecting
          Process reads IPFIX Messages.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        uses fileReaderParameters;
      }
    }

    grouping commonCollectorParameters {

      description "Parameters of a Collecting Process that are
        common to all transport protocols.";
      leaf localPort {
        type inet:port-number;
        description "If not configured, the Monitoring Device uses the
          default port number for IPFIX, which is 4739 without
          TLS or DTLS and 4740 if TLS or DTLS is activated.";
      }
      container transportLayerSecurity {
        presence "If transportLayerSecurity is present, DTLS is enabled
          if the transport protocol is SCTP or UDP, and TLS is enabled
          if the transport protocol is TCP.";
        description "TLS or DTLS configuration.";
        uses transportLayerSecurityParameters;
      }
      list transportSession {
        config false;
        description "This list contains the currently established
          Transport Sessions terminating at the given socket.";
        uses transportSessionParameters;
      }
    }

    grouping sctpCollectorParameters {
      description "Parameters of a listening SCTP socket at a
        Collecting Process.";
      uses commonCollectorParameters;
      leaf-list localIPAddress {
        type inet:ip-address;
        description "List of local IP addresses on which the
          Collecting Process listens for IPFIX Messages.  The IP
          addresses are used as eligible local IP addresses of the
          multihomed SCTP endpoint.";
        reference "RFC 4960, Section 6.4.";
      }
    }

    grouping udpCollectorParameters {
      description "Parameters of a listening UDP socket at a
        Collecting Process.";
      uses commonCollectorParameters;
      leaf-list localIPAddress {
        type inet:ip-address;
        description "List of local IP addresses on which the Collecting
          Process listens for IPFIX Messages.";
      }
      leaf templateLifeTime {
        type uint32;

        units seconds;
        default 1800;
        description "Sets the lifetime of Templates for all UDP
          Transport Sessions terminating at this UDP socket.
          Templates that are not received again within the configured
          lifetime become invalid at the Collecting Process.
          As specified in RFC 5101, the Template lifetime MUST be at
          least three times higher than the templateRefreshTimeout
          parameter value configured on the corresponding Exporting
          Processes.
          Note that this parameter corresponds to
          ipfixTransportSessionTemplateRefreshTimeout in the IPFIX
          MIB module.";
        reference "RFC 5101, Section 10.3.7; RFC 6615, Section 8
          (ipfixTransportSessionTemplateRefreshTimeout).";
      }
      leaf optionsTemplateLifeTime {
        type uint32;
        units seconds;
        default 1800;
        description "Sets the lifetime of Options Templates for all
          UDP Transport Sessions terminating at this UDP socket.
          Options Templates that are not received again within the
          configured lifetime become invalid at the Collecting
          Process.
          As specified in RFC 5101, the Options Template lifetime MUST
          be at least three times higher than the
          optionsTemplateRefreshTimeout parameter value configured on
          the corresponding Exporting Processes.
          Note that this parameter corresponds to
          ipfixTransportSessionOptionsTemplateRefreshTimeout in the
          IPFIX MIB module.";
        reference "RFC 5101, Section 10.3.7; RFC 6615, Section 8
          (ipfixTransportSessionOptionsTemplateRefreshTimeout).";
      }
      leaf templateLifePacket {
        type uint32;
        units "IPFIX Messages";
        description "If this parameter is configured, Templates
          defined in a UDP Transport Session become invalid if they
          are neither included in a sequence of more than this number
          of IPFIX Messages nor received again within the period of
          time specified by templateLifeTime.
          Note that this parameter corresponds to
          ipfixTransportSessionTemplateRefreshPacket in the IPFIX
          MIB module.";
        reference "RFC 5101, Section 10.3.7; RFC 6615, Section 8
          (ipfixTransportSessionTemplateRefreshPacket).";

      }
      leaf optionsTemplateLifePacket {
        type uint32;
        units "IPFIX Messages";
        description "If this parameter is configured, Options
          Templates defined in a UDP Transport Session become
          invalid if they are neither included in a sequence of more
          than this number of IPFIX Messages nor received again
          within the period of time specified by
          optionsTemplateLifeTime.
          Note that this parameter corresponds to
          ipfixTransportSessionOptionsTemplateRefreshPacket in the
          IPFIX MIB module.";
        reference "RFC 5101, Section 10.3.7; RFC 6615, Section 8
          (ipfixTransportSessionOptionsTemplateRefreshPacket).";
      }
    }

    grouping tcpCollectorParameters {
      description "Parameters of a listening TCP socket at a
        Collecting Process.";
      uses commonCollectorParameters;
      leaf-list localIPAddress {
        type inet:ip-address;
        description "List of local IP addresses on which the Collecting
          Process listens for IPFIX Messages.";
      }
    }

    grouping fileReaderParameters {
      description "File Reader parameters.";
      leaf file {
        type inet:uri;
        mandatory true;
        description "URI specifying the location of the file.";
      }
      leaf bytes {
        type yang:counter64;
        units octets;
        config false;
        description "The number of bytes read by the File Reader.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileReaderDiscontinuityTime.";
      }
      leaf messages {
        type yang:counter64;

        units "IPFIX Messages";
        config false;
        description "The number of IPFIX Messages read by the File
          Reader.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileReaderDiscontinuityTime.";
      }
      leaf records {
        type yang:counter64;
        units "Data Records";
        config false;
        description "The number of Data Records read by the File
          Reader.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileReaderDiscontinuityTime.";
      }
      leaf templates {
        type yang:counter32;
        units "Templates";
        config false;
        description "The number of Template Records (excluding
          Options Template Records) read by the File Reader.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileReaderDiscontinuityTime.";
      }
      leaf optionsTemplates {
        type yang:counter32;
        units "Options Templates";
        config false;
        description "The number of Options Template Records read by
          the File Reader.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          fileReaderDiscontinuityTime.";
      }
      leaf fileReaderDiscontinuityTime {
        type yang:date-and-time;
        config false;
        description "Timestamp of the most recent occasion at which
          one or more File Reader counters suffered a discontinuity.
          In contrast to discontinuity times in the IPFIX MIB module,

          the time is absolute and not relative to sysUpTime.";
      }
      list template {
        config false;
        description "This list contains the Templates and Options
          Templates that have been read by the File Reader.
          Withdrawn or invalidated (Options) Template MUST be removed
          from this list.";
        uses templateParameters;
      }
    }

    grouping transportLayerSecurityParameters {
      description "TLS or DTLS parameters.";
      leaf-list localCertificationAuthorityDN {
        type string;
        description "Distinguished names of certification authorities
          whose certificates may be used to identify the local
          endpoint.";
        reference "RFC 5280.";
      }
      leaf-list localSubjectDN {
        type string;
        description "Distinguished names that may be used in the
          certificates to identify the local endpoint.";
        reference "RFC 5280.";
      }
      leaf-list localSubjectFQDN {
        type inet:domain-name;
        description "Fully qualified domain names that may be used to
          in the certificates to identify the local endpoint.";
        reference "RFC 5280.";
      }
      leaf-list remoteCertificationAuthorityDN {
        type string;
        description "Distinguished names of certification authorities
          whose certificates are accepted to authorize remote
          endpoints.";
        reference "RFC 5280.";
      }
      leaf-list remoteSubjectDN {
        type string;
        description "Distinguished names which are accepted in
          certificates to authorize remote endpoints.";
        reference "RFC 5280.";
      }
      leaf-list remoteSubjectFQDN {
        type inet:domain-name;

        description "Fully qualified domain names that are accepted in
          certificates to authorize remote endpoints.";
        reference "RFC 5280.";
      }
    }

    grouping templateParameters {
      description "State parameters of a Template used by an Exporting
        Process or received by a Collecting Process in a specific
        Transport Session.  Parameter names and semantics correspond to
        the managed objects in IPFIX-MIB";
      reference "RFC 5101; RFC 6615, Section 8 (ipfixTemplateEntry,
        ipfixTemplateDefinitionEntry, ipfixTemplateStatsEntry)";
      leaf observationDomainId {
        type uint32;
        description "The ID of the Observation Domain for which this
          Template is defined.
          Note that this parameter corresponds to
          ipfixTemplateObservationDomainId in the IPFIX MIB module.";
        reference "RFC 6615, Section 8
          (ipfixTemplateObservationDomainId).";
      }
      leaf templateId {
        type uint16 {
          range "256..65535" {
            description "Valid range of Template IDs.";
            reference "RFC 5101";
          }
        }
        description "This number indicates the Template ID in the IPFIX
          message.
          Note that this parameter corresponds to ipfixTemplateId in
          the IPFIX MIB module.";
        reference "RFC 6615, Section 8 (ipfixTemplateId).";
      }
      leaf setId {
        type uint16;
        description "This number indicates the Set ID of the Template.
          Currently, there are two values defined.  The value 2 is used
          for Sets containing Template definitions.  The value 3 is
          used for Sets containing Options Template definitions.
          Note that this parameter corresponds to ipfixTemplateSetId
          in the IPFIX MIB module.";
        reference "RFC 6615, Section 8 (ipfixTemplateSetId).";
      }
      leaf accessTime {
        type yang:date-and-time;
        description "Used for Exporting Processes, this parameter

          contains the time when this (Options) Template was last
          sent to the Collector(s) or written to the file.
          Used for Collecting Processes, this parameter contains the
          time when this (Options) Template was last received from the
          Exporter or read from the file.
          Note that this parameter corresponds to
          ipfixTemplateAccessTime in the IPFIX MIB module.";
        reference "RFC 6615, Section 8 (ipfixTemplateAccessTime).";
      }
      leaf templateDataRecords {
        type yang:counter64;
        description "The number of transmitted or received Data
          Records defined by this (Options) Template.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          templateDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixTemplateDataRecords in the IPFIX MIB module.";
        reference "RFC 6615, Section 8 (ipfixTemplateDataRecords).";
      }
      leaf templateDiscontinuityTime {
        type yang:date-and-time;
        description "Timestamp of the most recent occasion at which
          the counter templateDataRecords suffered a discontinuity.
          Note that this parameter functionally corresponds to
          ipfixTemplateDiscontinuityTime in the IPFIX MIB module.
          In contrast to ipfixTemplateDiscontinuityTime, the time
          is absolute and not relative to sysUpTime.";
        reference "RFC 6615, Section 8
          (ipfixTemplateDiscontinuityTime).";
      }
      list field {
        description "This list contains the (Options) Template
          fields of which the (Options) Template is defined.
          The order of the list corresponds to the order of the fields
          in the (Option) Template Record.";
        leaf ieId {
          type ieIdType;
          description "This parameter indicates the Information
            Element identifier of the field.
            Note that this parameter corresponds to
            ipfixTemplateDefinitionIeId in the IPFIX MIB module.";
          reference "RFC 5101; RFC 6615, Section 8
            (ipfixTemplateDefinitionIeId).";
        }
        leaf ieLength {
          type uint16;

          units octets;
          description "This parameter indicates the length of the
            Information Element of the field.
            Note that this parameter corresponds to
            ipfixTemplateDefinitionIeLength in the IPFIX MIB
            module.";
          reference "RFC 5101; RFC 6615, Section 8
            (ipfixTemplateDefinitionIeLength).";
        }
        leaf ieEnterpriseNumber {
          type uint32;
          description "This parameter indicates the IANA enterprise
            number of the authority defining the Information Element
            identifier.
            If the Information Element is not enterprise-specific,
            this state parameter is zero.
            Note that this parameter corresponds to
            ipfixTemplateDefinitionIeEnterpriseNumber in the IPFIX
            MIB module.";
          reference "RFC 6615, Section 8
            (ipfixTemplateDefinitionIeEnterpriseNumber);
            IANA registry for Private Enterprise Numbers,
            http://www.iana.org/assignments/enterprise-numbers.";
        }
        leaf isFlowKey {
          when "../../setId = 2" {
            description "This parameter is available for non-Options
              Templates (Set ID is 2).";
          }
          type empty;
          description "If present, this is a Flow Key field.
            Note that this corresponds to flowKey(1) being set in
            ipfixTemplateDefinitionFlags.";
          reference "RFC 6615, Section 8
            (ipfixTemplateDefinitionFlags).";
        }
        leaf isScope {
          when "../../setId = 3" {
            description "This parameter is available for Options
              Templates (Set ID is 3).";
          }
          type empty;
          description "If present, this is a scope field.
            Note that this corresponds to scope(0) being set in
            ipfixTemplateDefinitionFlags.";
          reference "RFC 6615, Section 8
            (ipfixTemplateDefinitionFlags).";
        }

      }
    }

    grouping transportSessionParameters {
      description "State parameters of a Transport Session originating
        from an Exporting Process or terminating at a Collecting
        Process.  Parameter names and semantics correspond to the
        managed objects in IPFIX-MIB.";
      reference "RFC 5101; RFC 6615, Section 8
        (ipfixTransportSessionEntry,
         ipfixTransportSessionStatsEntry).";
      leaf ipfixVersion {
        type uint16;
        description "Used for Exporting Processes, this parameter
          contains the version number of the IPFIX protocol that the
          Exporter uses to export its data in this Transport Session.
          Hence, it is identical to the value of the configuration
          parameter ipfixVersion of the outer SctpExporter,
          UdpExporter, or TcpExporter node.
          Used for Collecting Processes, this parameter contains the
          version number of the IPFIX protocol it receives for
          this Transport Session.  If IPFIX Messages of different
          IPFIX protocol versions are received, this parameter
          contains the maximum version number.
          Note that this parameter corresponds to
          ipfixTransportSessionIpfixVersion in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionIpfixVersion).";
      }
      leaf sourceAddress {
        type inet:ip-address;
        description "The source address of the Exporter of the
          IPFIX Transport Session.
          If the transport protocol is SCTP, this is one of the
          potentially many IP addresses of the Exporter.
          Preferably, the source IP address of the path that is
          usually selected by the Exporter to send IPFIX Messages to
          the Collector SHOULD be used.
          Note that this parameter functionally corresponds to
          ipfixTransportSessionSourceAddressType and
          ipfixTransportSessionSourceAddress in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionSourceAddressType,
          ipfixTransportSessionSourceAddress);
          RFC 4960, Section 6.4.";
      }

      leaf destinationAddress {
        type inet:ip-address;
        description "The destination address of the Collector of
          the IPFIX Transport Session.
          If the transport protocol is SCTP, this is one of the
          potentially many IP addresses of the Collector.
          Preferably, the destination IP address of the path that is
          usually selected by the Exporter to send IPFIX Messages to
          the Collector SHOULD be used.
          Note that this parameter functionally corresponds to
          ipfixTransportSessionDestinationAddressType and
          ipfixTransportSessionDestinationAddress in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionDestinationAddressType,
          ipfixTransportSessionDestinationAddress);
          RFC 4960, Section 6.4.";
      }
      leaf sourcePort {
        type inet:port-number;
        description "The transport-protocol port number of the
          Exporter of the IPFIX Transport Session.
          Note that this parameter corresponds to
          ipfixTransportSessionSourcePort in the IPFIX MIB module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionSourcePort).";
      }
      leaf destinationPort {
        type inet:port-number;
        description "The transport-protocol port number of the
          Collector of the IPFIX Transport Session.
          Note that this parameter corresponds to
          ipfixTransportSessionDestinationPort in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionDestinationPort).";
      }
      leaf sctpAssocId {
        type uint32;
        description "The association ID used for the SCTP session
          between the Exporter and the Collector of the IPFIX
          Transport Session.  It is equal to the sctpAssocId entry
          in the sctpAssocTable defined in the SCTP-MIB.
          This parameter is only available if the transport protocol
          is SCTP and if an SNMP agent on the same Monitoring Device
          enables access to the corresponding MIB objects in the
          sctpAssocTable.
          Note that this parameter corresponds to

          ipfixTransportSessionSctpAssocId in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionSctpAssocId);
          RFC 3871";
      }
      leaf status {
        type transportSessionStatus;
        description "Status of the Transport Session.
          Note that this parameter corresponds to
          ipfixTransportSessionStatus in the IPFIX MIB module.";
        reference "RFC 6615, Section 8 (ipfixTransportSessionStatus).";
      }
      leaf rate {
        type yang:gauge32;
        units "bytes per second";
        description "The number of bytes per second transmitted by the
          Exporting Process or received by the Collecting Process.
          This parameter is updated every second.
          Note that this parameter corresponds to
          ipfixTransportSessionRate in the IPFIX MIB module.";
        reference "RFC 6615, Section 8 (ipfixTransportSessionRate).";
      }
      leaf bytes {
        type yang:counter64;
        units bytes;
        description "The number of bytes transmitted by the
          Exporting Process or received by the Collecting Process.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          transportSessionDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixTransportSessionBytes in the IPFIX MIB module.";
        reference "RFC 6615, Section 8 (ipfixTransportSessionBytes).";
      }
      leaf messages {
        type yang:counter64;
        units "IPFIX Messages";
        description "The number of messages transmitted by the
          Exporting Process or received by the Collecting Process.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          transportSessionDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixTransportSessionMessages in the IPFIX MIB module.";
        reference "RFC 6615, Section 8

          (ipfixTransportSessionMessages).";
      }
      leaf discardedMessages {
        type yang:counter64;
        units "IPFIX Messages";
        description "Used for Exporting Processes, this parameter
          indicates the number of messages that could not be sent due
          to internal buffer overflows, network congestion, routing
          issues, etc.  Used for Collecting Process, this parameter
          indicates the number of received IPFIX Message that are
          malformed, cannot be decoded, are received in the wrong
          order or are missing according to the sequence number.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          transportSessionDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixTransportSessionDiscardedMessages in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionDiscardedMessages).";
      }
      leaf records {
        type yang:counter64;
        units "Data Records";
        description "The number of Data Records transmitted by the
          Exporting Process or received by the Collecting Process.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          transportSessionDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixTransportSessionRecords in the IPFIX MIB module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionRecords).";
      }
      leaf templates {
        type yang:counter32;
        units "Templates";
        description "The number of Templates transmitted by the
          Exporting Process or received by the Collecting Process.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          transportSessionDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixTransportSessionTemplates in the IPFIX MIB module.";
        reference "RFC 6615, Section 8

          (ipfixTransportSessionTemplates).";
      }
      leaf optionsTemplates {
        type yang:counter32;
        units "Options Templates";
        description "The number of Option Templates transmitted by the
          Exporting Process or received by the Collecting Process.
          Discontinuities in the value of this counter can occur at
          re-initialization of the management system, and at other
          times as indicated by the value of
          transportSessionDiscontinuityTime.
          Note that this parameter corresponds to
          ipfixTransportSessionOptionsTemplates in the IPFIX MIB
          module.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionOptionsTemplates).";
      }
      leaf transportSessionStartTime {
        type yang:date-and-time;
        description "Timestamp of the start of the given Transport
          Session.
          This state parameter does not correspond to any object in
          the IPFIX MIB module.";
      }
      leaf transportSessionDiscontinuityTime {
        type yang:date-and-time;
        description "Timestamp of the most recent occasion at which
          one or more of the Transport Session counters suffered a
          discontinuity.
          Note that this parameter functionally corresponds to
          ipfixTransportSessionDiscontinuityTime in the IPFIX MIB
          module.  In contrast to
          ipfixTransportSessionDiscontinuityTime, the time is
          absolute and not relative to sysUpTime.";
        reference "RFC 6615, Section 8
          (ipfixTransportSessionDiscontinuityTime).";
      }
      list template {
        description "This list contains the Templates and Options
          Templates that are transmitted by the Exporting Process
          or received by the Collecting Process.
          Withdrawn or invalidated (Options) Templates MUST be removed
          from this list.";
        uses templateParameters;
      }
    }

    /*****************************************************************
    * Main container
    *****************************************************************/

    container ipfix {
      description "Top-level node of the IPFIX/PSAMP configuration
        data model.";
      list collectingProcess {
        if-feature collector;
        key name;
        description "Collecting Process of the Monitoring Device.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        uses collectingProcessParameters;
        leaf-list exportingProcess {
          if-feature exporter;
          type leafref { path "/ipfix/exportingProcess/name"; }
          description "Export of received records without any
            modifications.  Records are processed by all Exporting
            Processes in the list.";
        }
      }

      list observationPoint {
        if-feature meter;
        key name;
        description "Observation Point of the Monitoring Device.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        uses observationPointParameters;
        leaf-list selectionProcess {
          type leafref { path "/ipfix/selectionProcess/name"; }
          description "Selection Processes in this list process
            packets in parallel.";
        }
      }

      list selectionProcess {
        if-feature meter;
        key name;
        description "Selection Process of the Monitoring Device.";
        leaf name {
          type nameType;
          description "Key of this list.";

        }
        list selector {
          key name;
          min-elements 1;
          ordered-by user;
          description "List of Selectors that define the action of the
            Selection Process on a single packet.  The Selectors are
            serially invoked in the same order as they appear in this
            list.";
          leaf name {
            type nameType;
            description "Key of this list.";
          }
          uses selectorParameters;
        }
        list selectionSequence {
          config false;
          description "This list contains the Selection Sequence IDs
            that are assigned by the Monitoring Device to distinguish
            different Selection Sequences passing through the
            Selection Process.
            As Selection Sequence IDs are unique per Observation
            Domain, the corresponding Observation Domain IDs are
            included as well.
            With this information, it is possible to associate
            Selection Sequence (Statistics) Report Interpretations
            exported according to the PSAMP protocol with a Selection
            Process in the configuration data.";
          reference "RFC 5476.";
          leaf observationDomainId {
            type uint32;
            description "Observation Domain ID for which the
              Selection Sequence ID is assigned.";
          }
          leaf selectionSequenceId {
            type uint64;
            description "Selection Sequence ID used in the Selection
              Sequence (Statistics) Report Interpretation.";
          }
        }
        leaf cache {
          type leafref { path "/ipfix/cache/name"; }
          description "Cache that receives the output of the
            Selection Process.";
        }
      }

      list cache {

        if-feature meter;
        key name;
        description "Cache of the Monitoring Device.";
        leaf name {
          type nameType;
          description "Key of this list.";
        }
        leaf meteringProcessId {
          type uint32;
          config false;
          description "The identifier of the Metering Process this
            Cache belongs to.
            This parameter corresponds to the Information Element
            meteringProcessId.  Its occurrence helps to associate
            Cache parameters with Metering Process statistics
            exported by the Monitoring Device using the Metering
            Process (Reliability) Statistics Template as
            defined by the IPFIX protocol specification.";
          reference "RFC 5101, Sections 4.1 and 4.2;
            IANA registry for IPFIX Entities,
            http://www.iana.org/assignments/ipfix.";
        }
        leaf dataRecords {
          type yang:counter64;
          units "Data Records";
          config false;
          description "The number of Data Records generated by this
            Cache.
            Discontinuities in the value of this counter can occur at
            re-initialization of the management system, and at other
            times as indicated by the value of
            cacheDiscontinuityTime.
            Note that this parameter corresponds to
            ipfixMeteringProcessDataRecords in the IPFIX MIB
            module.";
          reference "RFC 6615, Section 8
            (ipfixMeteringProcessDataRecords).";
        }
        leaf cacheDiscontinuityTime {
          type yang:date-and-time;
          config false;
          description "Timestamp of the most recent occasion at which
            the counter dataRecords suffered a discontinuity.
            Note that this parameter functionally corresponds to
            ipfixMeteringProcessDiscontinuityTime in the IPFIX MIB
            module.  In contrast to
            ipfixMeteringProcessDiscontinuityTime, the time is
            absolute and not relative to sysUpTime.";

          reference "RFC 6615, Section 8
            (ipfixMeteringProcessDiscontinuityTime).";
        }
        choice CacheType {
          mandatory true;
          description "Type of Cache and specific parameters.";
          container immediateCache {
            if-feature immediateCache;
            description "Flow expiration after the first packet;
              generation of Packet Records.";
            uses cacheLayoutParameters;
          }
          container timeoutCache {
            if-feature timeoutCache;
            description "Flow expiration after active and idle
              timeout; generation of Flow Records.";
            uses flowCacheParameters;
            uses cacheLayoutParameters;
          }
          container naturalCache {
            if-feature naturalCache;
            description "Flow expiration after active and idle
              timeout, or on natural termination (e.g., TCP FIN or
              TCP RST) of the Flow; generation of Flow Records.";
            uses flowCacheParameters;
            uses cacheLayoutParameters;
          }
          container permanentCache {
            if-feature permanentCache;
            description "No flow expiration, periodical export with
              time interval exportInterval; generation of Flow
              Records.";
            uses flowCacheParameters;
            uses cacheLayoutParameters;
          }
        }
        leaf-list exportingProcess {
          if-feature exporter;
          type leafref { path "/ipfix/exportingProcess/name"; }
          description "Records are exported by all Exporting Processes
            in the list.";
        }
      }

      list exportingProcess {
        if-feature exporter;
        key name;
        description "Exporting Process of the Monitoring Device.";

        leaf name {
          type nameType;
          description "Key of this list.";
        }
        uses exportingProcessParameters;
      }
    }
  }
  <CODE ENDS>

7.  Examples

   This section shows example configurations conforming to the YANG
   module specified in Section 6.

7.1.  PSAMP Device

   This configuration example configures two Observation Points
   capturing ingress traffic at eth0 and all traffic at eth1.  Both
   Observed Packet Streams enter two different Selection Processes.  The
   first Selection Process implements a Composite Selector of a filter
   for UDP packets and a random sampler.  The second Selection Process
   implements a Primitive Selector of an ICMP filter.  The Selected
   Packet Streams of both Selection Processes enter the same Cache.  The
   Cache generates a PSAMP Packet Report for every selected packet.

   The associated Exporting Process exports to a Collector using PR-SCTP
   and DTLS.  The TLS/DTLS parameters specify that the collector must
   supply a certificate for the FQDN collector.example.net.  Valid
   certificates from any certification authority will be accepted.  As
   the destination transport port is omitted, the standard IPFIX-over-
   DTLS port 4740 is used.

   The parameters of the Selection Processes are reported as Selection
   Sequence Report Interpretations and Selector Report Interpretations
   [RFC5476].  There will be two Selection Sequence Report
   Interpretations per Selection Process, one for each Observation
   Point.  Selection Sequence Statistics Report Interpretations are
   exported every 30 seconds (30000 milliseconds).

   <ipfix xmlns="urn:ietf:params:xml:ns:yang:ietf-ipfix-psamp">

     <observationPoint>
       <name>OP at eth0 (ingress)</name>
       <observationDomainId>123</observationDomainId>
       <ifName>eth0</ifName>
       <direction>ingress</direction>
       <selectionProcess>Sampled UDP packets</selectionProcess>

       <selectionProcess>ICMP packets</selectionProcess>
     </observationPoint>

     <observationPoint>
       <name>OP at eth1</name>
       <observationDomainId>123</observationDomainId>
       <ifName>eth1</ifName>
       <selectionProcess>Sampled UDP packets</selectionProcess>
       <selectionProcess>ICMP packets</selectionProcess>
     </observationPoint>

     <selectionProcess>
       <name>Sampled UDP packets</name>
       <selector>
         <name>UDP filter</name>
         <filterMatch>
           <ieId>4</ieId>
           <value>17</value>
         </filterMatch>
       </selector>
       <selector>
         <name>10-out-of-100 sampler</name>
         <sampRandOutOfN>
           <size>10</size>
           <population>100</population>
         </sampRandOutOfN>
       </selector>
       <cache>PSAMP cache</cache>
     </selectionProcess>

     <selectionProcess>
       <name>ICMP packets</name>
       <selector>
         <name>ICMP filter</name>
         <filterMatch>
           <ieId>4</ieId>
           <value>1</value>
         </filterMatch>
       </selector>
       <cache>PSAMP cache</cache>
     </selectionProcess>

     <cache>
       <name>PSAMP cache</name>
       <immediateCache>
         <cacheLayout>
           <cacheField>
             <name>Field 1: ipHeaderPacketSection</name>

             <ieId>313</ieId>
             <ieLength>64</ieLength>
           </cacheField>
           <cacheField>
             <name>Field 2: observationTimeMilliseconds</name>
             <ieId>322</ieId>
           </cacheField>
         </cacheLayout>
       </immediateCache>
       <exportingProcess>The only exporter</exportingProcess>
     </cache>

     <exportingProcess>
       <name>The only exporter</name>
       <destination>
         <name>PR-SCTP collector</name>
         <sctpExporter>
           <destinationIPAddress>192.0.2.1</destinationIPAddress>
           <rateLimit>1000000</rateLimit>
           <timedReliability>500</timedReliability>
           <transportLayerSecurity>
             <remoteSubjectFQDN>coll-1.example.net</remoteSubjectFQDN>
           </transportLayerSecurity>
         </sctpExporter>
       </destination>
       <options>
         <name>Options 1</name>
         <optionsType>selectionSequence</optionsType>
         <optionsTimeout>0</optionsTimeout>
       </options>
       <options>
         <name>Options 2</name>
         <optionsType>selectionStatistics</optionsType>
         <optionsTimeout>30000</optionsTimeout>
       </options>
     </exportingProcess>

   </ipfix>

   The above configuration results in one Template and six Options
   Templates.  For the remainder of the example, we assume Template ID
   256 for the Template and Template IDs 257 to 262 for the Options
   Templates.  The Template is used to export the Packet Reports and has
   the following fields:

      Template ID: 256
      ipHeaderPacketSection (elementId = 313, length = 64)
      observationTimeMilliseconds (elementId = 322, length = 8)

   Two Options Templates are used for the Selection Sequence Report
   Interpretations.  The first one has one selectorId field and is used
   for the Selection Process "ICMP packets".  The second one has two
   selectorId fields to describe the two selectors of the Selection
   Process "Sampled UDP packets".

      Template ID: 257
      Scope: selectionSequenceId (elementId = 301, length = 8)
      observationPointId (elementId = 138, length = 4)
      selectorId (elementId = 302, length = 4)

      Template ID: 258
      Scope: selectionSequenceId (elementId = 301, length = 8)
      observationPointId (elementId = 138, length = 4)
      selectorId (elementId = 302, length = 4)
      selectorId (elementId = 302, length = 4)

   Another Options Template is used to carry the Property Match
   Filtering Selector Report Interpretation for the Selectors "UDP
   filter" and "ICMP filter":

      Template ID: 259
      Scope: selectorId (elementId = 302, length = 4)
      selectorAlgorithm (elementId = 304, length = 2)
      protocolIdentifier (elementId = 4, length = 1)

   Yet another Options Template is used to carry the Random n-out-of-N
   Sampling Selector Report Interpretation for the Selector "10-out-of-
   100 sampler":

      Template ID: 260
      Scope: selectorId (elementId = 302, length = 4)
      selectorAlgorithm (elementId = 304, length = 2)
      samplingSize (elementId = 319, length = 4)
      samplingPopulation (elementId = 310, length = 4)

   The last two Options Template are used to carry the Selection
   Sequence Statistics Report Interpretation for the Selection
   Processes, containing the statistics for one and two Selectors,
   respectively:

      Template ID: 261
      Scope: selectionSequenceId (elementId = 301, length = 8)
      selectorIdTotalPktsObserved (elementId = 318, length = 8)
      selectorIdTotalPktsSelected (elementId = 319, length = 8)

      Template ID: 262
      Scope: selectionSequenceId (elementId = 301, length = 8)
      selectorIdTotalPktsObserved (elementId = 318, length = 8)
      selectorIdTotalPktsSelected (elementId = 319, length = 8)
      selectorIdTotalPktsObserved (elementId = 318, length = 8)
      selectorIdTotalPktsSelected (elementId = 319, length = 8)

   After a short runtime, 100 packets have been observed at the two
   Observation Points, including 20 UDP and 5 ICMP packets. 3 of the UDP
   packets are selected by the random sampler, which results in a total
   of 8 Packet Reports generated by the Cache.  Under these
   circumstances, the complete configuration and state data of the PSAMP
   Device may look as follows:

   <ipfix xmlns="urn:ietf:params:xml:ns:yang:ietf-ipfix-psamp">

     <observationPoint>
       <name>OP at eth0 (ingress)</name>
       <observationPointId>1</observationPointId>
       <observationDomainId>123</observationDomainId>
       <ifName>eth0</ifName>
       <direction>ingress</direction>
       <selectionProcess>Sampled UDP packets</selectionProcess>
       <selectionProcess>ICMP packets</selectionProcess>
     </observationPoint>

     <observationPoint>
       <name>OP at eth1</name>
       <observationPointId>2</observationPointId>
       <observationDomainId>123</observationDomainId>
       <ifName>eth1</ifName>
       <direction>both</direction>
       <selectionProcess>Sampled UDP packets</selectionProcess>
       <selectionProcess>ICMP packets</selectionProcess>
     </observationPoint>

     <selectionProcess>
       <name>Sampled UDP packets</name>
       <selector>
         <name>UDP filter</name>
         <filterMatch>
           <ieId>4</ieId>
           <value>17</value>
         </filterMatch>
         <packetsObserved>100</packetsObserved>
         <packetsDropped>80</packetsDropped>
         <selectorDiscontinuityTime>2010-03-15T00:00:00.00Z
             </selectorDiscontinuityTime>

       </selector>
       <selector>
         <name>10-out-of-100 sampler</name>
         <sampRandOutOfN>
           <size>10</size>
           <population>100</population>
         </sampRandOutOfN>
         <packetsObserved>20</packetsObserved>
         <packetsDropped>17</packetsDropped>
         <selectorDiscontinuityTime>2010-03-15T00:00:00.00Z
             </selectorDiscontinuityTime>
       </selector>
       <selectionSequence>
           <observationDomainId>123</observationDomainId>
           <selectionSequenceId>1</selectionSequenceId>
       </selectionSequence>
       <selectionSequence>
           <observationDomainId>123</observationDomainId>
           <selectionSequenceId>2</selectionSequenceId>
       </selectionSequence>
       <cache>PSAMP cache</cache>
     </selectionProcess>

     <selectionProcess>
       <name>ICMP packets</name>
       <selector>
         <name>ICMP filter</name>
         <filterMatch>
           <ieId>4</ieId>
           <value>1</value>
         </filterMatch>
         <packetsObserved>100</packetsObserved>
         <packetsDropped>95</packetsDropped>
         <selectorDiscontinuityTime>2010-03-15T00:00:00.00Z
             </selectorDiscontinuityTime>
       </selector>
       <selectionSequence>
           <observationDomainId>123</observationDomainId>
           <selectionSequenceId>3</selectionSequenceId>
       </selectionSequence>
       <selectionSequence>
           <observationDomainId>123</observationDomainId>
           <selectionSequenceId>4</selectionSequenceId>
       </selectionSequence>
       <cache>PSAMP cache</cache>
     </selectionProcess>

     <cache>

       <name>PSAMP cache</name>
       <meteringProcessId>1</meteringProcessId>
       <immediateCache>
         <cacheLayout>
           <cacheField>
             <name>Field 1: ipHeaderPacketSection</name>
             <ieId>313</ieId>
             <ieLength>64</ieLength>
           </cacheField>
           <cacheField>
             <name>Field 2: observationTimeMilliseconds</name>
             <ieId>322</ieId>
           </cacheField>
         </cacheLayout>
       </immediateCache>
       <dataRecords>8</dataRecords>
       <cacheDiscontinuityTime>2010-03-15T00:00:00.00Z
           </cacheDiscontinuityTime>
       <exportingProcess>The only exporter</exportingProcess>
     </cache>

     <exportingProcess>
       <name>The only exporter</name>
       <exportingProcessId>1</exportingProcessId>
       <exportMode>parallel</exportMode>
       <destination>
         <name>PR-SCTP collector</name>
         <sctpExporter>
           <ipfixVersion>10</ipfixVersion>
           <destinationIPAddress>192.0.2.1</destinationIPAddress>
           <destinationPort>4740</destinationPort>
           <sendBufferSize>32768</sendBufferSize>
           <rateLimit>1000000</rateLimit>
           <timedReliability>500</timedReliability>
           <transportLayerSecurity>
             <remoteSubjectFQDN>coll-1.example.net</remoteSubjectFQDN>
           </transportLayerSecurity>
           <transportSession>
             <ipfixVersion>10</ipfixVersion>
             <sourceAddress>192.0.2.100</sourceAddress>
             <destinationAddress>192.0.2.1</destinationAddress>
             <sourcePort>45687</sourcePort>
             <destinationPort>4740</destinationPort>
             <sctpAssocId>1</sctpAssocId>
             <status>active</status>
             <rate>230</rate>
             <bytes>978</bytes>
             <messages>3</messages>

             <records>19</records>
             <templates>1</templates>
             <optionsTemplates>6</optionsTemplates>
             <transportSessionStartTime>2010-03-15T00:00:00.50Z
                 </transportSessionStartTime>
             <template>
               <observationDomainId>123</observationDomainId>
               <templateId>256</templateId>
               <setId>2</setId>
               <accessTime>2010-03-15T00:00:02.15Z</accessTime>
               <templateDataRecords>8</templateDataRecords>
               <templateDiscontinuityTime>2010-03-15T00:00:01.10Z
                   </templateDiscontinuityTime>
               <field>
                 <ieId>313</ieId>
                 <ieLength>64</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>154</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
             </template>
             <template>
               <observationDomainId>123</observationDomainId>
               <templateId>257</templateId>
               <setId>3</setId>
               <accessTime>2010-03-15T00:00:02.15Z</accessTime>
               <templateDataRecords>2</templateDataRecords>
               <templateDiscontinuityTime>2010-03-15T00:00:01.10Z
                   </templateDiscontinuityTime>
               <field>
                 <ieId>301</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
                 <isScope/>
               </field>
               <field>
                 <ieId>138</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>302</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>

             </template>
             <template>
               <observationDomainId>123</observationDomainId>
               <templateId>258</templateId>
               <setId>3</setId>
               <accessTime>2010-03-15T00:00:02.15Z</accessTime>
               <templateDataRecords>2</templateDataRecords>
               <templateDiscontinuityTime>2010-03-15T00:00:01.10Z
                   </templateDiscontinuityTime>
               <field>
                 <ieId>301</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
                 <isScope/>
               </field>
               <field>
                 <ieId>138</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>302</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>302</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
             </template>
             <template>
               <observationDomainId>123</observationDomainId>
               <templateId>259</templateId>
               <setId>3</setId>
               <accessTime>2010-03-15T00:00:02.15Z</accessTime>
               <templateDataRecords>2</templateDataRecords>
               <templateDiscontinuityTime>2010-03-15T00:00:01.10Z
                   </templateDiscontinuityTime>
               <field>
                 <ieId>302</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
                 <isScope/>
               </field>
               <field>
                 <ieId>304</ieId>
                 <ieLength>2</ieLength>

                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>4</ieId>
                 <ieLength>1</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
             </template>
             <template>
               <observationDomainId>123</observationDomainId>
               <templateId>260</templateId>
               <setId>3</setId>
               <accessTime>2010-03-15T00:00:02.15Z</accessTime>
               <templateDataRecords>1</templateDataRecords>
               <templateDiscontinuityTime>2010-03-15T00:00:01.10Z
                   </templateDiscontinuityTime>
               <field>
                 <ieId>302</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
                 <isScope/>
               </field>
               <field>
                 <ieId>304</ieId>
                 <ieLength>2</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>309</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>310</ieId>
                 <ieLength>4</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
             </template>
             <template>
               <observationDomainId>123</observationDomainId>
               <templateId>261</templateId>
               <setId>3</setId>
               <accessTime>2010-03-15T00:00:03.10Z</accessTime>
               <templateDataRecords>2</templateDataRecords>
               <templateDiscontinuityTime>2010-03-15T00:00:01.10Z
                   </templateDiscontinuityTime>
               <field>
                 <ieId>301</ieId>

                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
                 <isScope/>
               </field>
               <field>
                 <ieId>318</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>319</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
             </template>
             <template>
               <observationDomainId>123</observationDomainId>
               <templateId>262</templateId>
               <setId>3</setId>
               <accessTime>2010-03-15T00:00:03.10Z</accessTime>
               <templateDataRecords>2</templateDataRecords>
               <templateDiscontinuityTime>2010-03-15T00:00:01.10Z
                   </templateDiscontinuityTime>
               <field>
                 <ieId>301</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
                 <isScope/>
               </field>
               <field>
                 <ieId>318</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>319</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>318</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>
               </field>
               <field>
                 <ieId>319</ieId>
                 <ieLength>8</ieLength>
                 <ieEnterpriseNumber>0</ieEnterpriseNumber>

               </field>
             </template>
           </transportSession>
         </sctpExporter>
       </destination>
       <options>
         <name>Options 1</name>
         <optionsType>selectionSequence</optionsType>
         <optionsTimeout>0</optionsTimeout>
       </options>
       <options>
         <name>Options 2</name>
         <optionsType>selectionStatistics</optionsType>
         <optionsTimeout>30000</optionsTimeout>
       </options>
     </exportingProcess>

   </ipfix>

7.2.  IPFIX Device

   This configuration example demonstrates the shared usage of a Cache
   for maintaining Flow Records from two Observation Points belonging to
   different Observation Domains.  Packets are selected using different
   Sampling techniques: count-based Sampling for the first Observation
   Point (eth0) and selection of all packets for the second Observation
   Point (eth1).  The Exporting Process sends the Flow Records to a
   primary destination using SCTP.  A UDP Collector is specified as
   secondary destination.

   Exporting Process reliability statistics [RFC5101] are exported
   periodically every minute (60000 milliseconds).  Selection Sequence
   Report Interpretations and Selector Report Interpretations [RFC5476]
   are exported once after configuring the Selection Processes.  In
   total, two Selection Sequence Report Interpretations will be
   exported, one for each Selection Process.

   <ipfix xmlns="urn:ietf:params:xml:ns:yang:ietf-ipfix-psamp">

     <observationPoint>
       <name>OP at eth0 (ingress)</name>
       <observationDomainId>123</observationDomainId>
       <ifName>eth0</ifName>
       <direction>ingress</direction>
       <selectionProcess>Count-based packet selection</selectionProcess>
     </observationPoint>

     <observationPoint>

       <name>OP at eth1</name>
       <observationDomainId>456</observationDomainId>
       <ifName>eth1</ifName>
       <selectionProcess>All packet selection</selectionProcess>
     </observationPoint>

     <selectionProcess>
       <name>Count-based packet selection</name>
       <selector>
         <name>Count-based sampler</name>
         <sampCountBased>
           <packetInterval>1</packetInterval>
           <packetSpace>99</packetSpace>
         </sampCountBased>
       </selector>
       <cache>Flow cache</cache>
     </selectionProcess>

     <selectionProcess>
       <name>All packet selection</name>
       <selector>
         <name>Select all</name>
         <selectAll/>
       </selector>
       <cache>Flow cache</cache>
     </selectionProcess>

     <cache>
       <name>Flow cache</name>
       <timeoutCache>
         <maxFlows>4096</maxFlows>
         <activeTimeout>5000</activeTimeout>
         <idleTimeout>10000</idleTimeout>
         <cacheLayout>
           <cacheField>
             <name>Field 1</name>
             <ieName>sourceIPv4Address</ieName>
             <isFlowKey/>
           </cacheField>
           <cacheField>
             <name>Field 2</name>
             <ieName>destinationIPv4Address</ieName>
             <isFlowKey/>
           </cacheField>
           <cacheField>
             <name>Field 3</name>
             <ieName>protocolIdentifier</ieName>
             <isFlowKey/>

           </cacheField>
           <cacheField>
             <name>Field 4</name>
             <ieName>sourceTransportPort</ieName>
             <isFlowKey/>
           </cacheField>
           <cacheField>
             <name>Field 5</name>
             <ieName>destinationTransportPort</ieName>
             <isFlowKey/>
           </cacheField>
           <cacheField>
             <name>Field 6</name>
             <ieName>flowStartMilliseconds</ieName>
           </cacheField>
           <cacheField>
             <name>Field 7</name>
             <ieName>flowEndSeconds</ieName>
           </cacheField>
           <cacheField>
             <name>Field 8</name>
             <ieName>octetDeltaCount</ieName>
           </cacheField>
           <cacheField>
             <name>Field 9</name>
             <ieName>packetDeltaCount</ieName>
           </cacheField>
         </cacheLayout>
       </timeoutCache>
       <exportingProcess>SCTP export with UDP backup</exportingProcess>
     </cache>

     <exportingProcess>
       <name>SCTP export with UDP backup</name>
       <exportMode>fallback</exportMode>
       <destination>
         <name>SCTP destination (primary)</name>
         <sctpExporter>
           <destinationPort>4739</destinationPort>
           <destinationIPAddress>192.0.2.1</destinationIPAddress>
         </sctpExporter>
       </destination>
       <destination>
         <name>UDP destination (secondary)</name>
         <udpExporter>
           <destinationPort>4739</destinationPort>
           <destinationIPAddress>192.0.2.2</destinationIPAddress>
           <templateRefreshTimeout>300</templateRefreshTimeout>

           <optionsTemplateRefreshTimeout>300
               </optionsTemplateRefreshTimeout>
         </udpExporter>
       </destination>
       <options>
         <name>Options 1</name>
         <optionsType>selectionSequence</optionsType>
         <optionsTimeout>0</optionsTimeout>
       </options>
       <options>
         <name>Options 2</name>
         <optionsType>exportingReliability</optionsType>
         <optionsTimeout>60000</optionsTimeout>
       </options>
     </exportingProcess>

   </ipfix>

7.3.  Export of Flow Records and Packet Reports

   This configuration example demonstrates the combined export of Flow
   Records and Packet Reports for a single Observation Point.  One
   Selection Process applies random Sampling to the Observed Packet
   Stream.  Its output is passed to a Cache generating Flow Records.  In
   parallel, the Observed Packet Stream enters a second Selection
   Process that discards all non-ICMP packets and passes the selected
   packets to a second Cache for generating Packet Reports.  The output
   of both Caches is exported to a single Collector using SCTP.

   <ipfix xmlns="urn:ietf:params:xml:ns:yang:ietf-ipfix-psamp">

     <observationPoint>
       <name>OP at linecard 3</name>
       <observationDomainId>9876</observationDomainId>
       <ifIndex>4</ifIndex>
       <direction>ingress</direction>
       <selectionProcess>Sampling</selectionProcess>
       <selectionProcess>ICMP</selectionProcess>
     </observationPoint>

     <selectionProcess>
       <name>Sampling</name>
       <selector>
         <name>Random sampler</name>
         <sampUniProb>
           <probability>0.01</probability>
         </sampUniProb>
       </selector>

       <cache>Flow cache</cache>
     </selectionProcess>

     <selectionProcess>
       <name>ICMP</name>
       <selector>
         <name>ICMP filter</name>
         <filterMatch>
           <ieId>4</ieId>
           <value>1</value>
         </filterMatch>
       </selector>
       <cache>Packet reporting</cache>
     </selectionProcess>

     <cache>
       <name>Flow cache</name>
       <timeoutCache>
         <maxFlows>4096</maxFlows>
         <activeTimeout>5</activeTimeout>
         <idleTimeout>10</idleTimeout>
         <cacheLayout>
           <cacheField>
             <name>Field 1</name>
             <ieName>sourceIPv4Address</ieName>
             <isFlowKey/>
           </cacheField>
           <cacheField>
             <name>Field 2</name>
             <ieName>destinationIPv4Address</ieName>
             <isFlowKey/>
           </cacheField>
           <cacheField>
             <name>Field 6</name>
             <ieName>flowStartMilliseconds</ieName>
           </cacheField>
           <cacheField>
             <name>Field 7</name>
             <ieName>flowEndSeconds</ieName>
           </cacheField>
           <cacheField>
             <name>Field 8</name>
             <ieName>octetDeltaCount</ieName>
           </cacheField>
           <cacheField>
             <name>Field 9</name>
             <ieName>packetDeltaCount</ieName>
           </cacheField>

         </cacheLayout>
       </timeoutCache>
       <exportingProcess>Export</exportingProcess>
     </cache>

     <cache>
       <name>Packet reporting</name>
       <immediateCache>
         <cacheLayout>
           <cacheField>
             <name>Field 1</name>
             <ieId>313</ieId>
             <ieLength>64</ieLength>
           </cacheField>
           <cacheField>
             <name>Field 2</name>
             <ieId>154</ieId>
           </cacheField>
         </cacheLayout>
       </immediateCache>
       <exportingProcess>Export</exportingProcess>
     </cache>

     <exportingProcess>
       <name>Export</name>
       <destination>
         <name>SCTP collector</name>
         <sctpExporter>
           <destinationIPAddress>192.0.2.1</destinationIPAddress>
           <timedReliability>0</timedReliability>
         </sctpExporter>
       </destination>
       <options>
         <name>Options 1</name>
         <optionsType>selectionSequence</optionsType>
         <optionsTimeout>0</optionsTimeout>
       </options>
     </exportingProcess>

   </ipfix>

7.4.  Collector and File Writer

   This configuration example configures a Collector that writes the
   received data to a file.

   <ipfix xmlns="urn:ietf:params:xml:ns:yang:ietf-ipfix-psamp">

     <collectingProcess>
       <name>SCTP collector</name>
       <sctpCollector>
         <name>Listening port 4739</name>
         <localPort>4739</localPort>
         <localIPAddress>192.0.2.1</localIPAddress>
       </sctpCollector>
       <exportingProcess>File writer</exportingProcess>
     </collectingProcess>

     <exportingProcess>
       <name>File writer</name>
       <destination>
         <name>Write to /tmp folder</name>
         <fileWriter>
           <file>file://tmp/collected-records.ipfix</file>
         </fileWriter>
       </destination>
     </exportingProcess>

   </ipfix>

7.5.  Deviations

   Assume that a Monitoring Device has only two interfaces ifIndex=1 and
   ifIndex=2, which can be configured as Observation Points.  The
   Observation Point ID is always identical to the ifIndex.

   The following YANG module specifies these deviations.

module my-ipfix-psamp-deviation {
  namespace "urn:my-company:xml:ns:ietf-ipfix-psamp";
  prefix my;

  import ietf-ipfix-psamp { prefix ipfix; }

  deviation /ipfix:ipfix/ipfix:observationPoint/ipfix:entPhysicalIndex {
    deviate not-supported;
  }
  deviation /ipfix:ipfix/ipfix:observationPoint/ipfix:entPhysicalName {
    deviate not-supported;
  }
  deviation /ipfix:ipfix/ipfix:observationPoint/ipfix:ifName {
    deviate not-supported;
  }
  deviation /ipfix:ipfix/ipfix:observationPoint {
    deviate add {
      must "ipfix:ifIndex=1 or ipfix:ifIndex=2";
    }
  }
  deviation
      /ipfix:ipfix/ipfix:observationPoint/ipfix:observationPointId {
    deviate add {
      must "current()=../ipfix:ifIndex";
    }
  }
}

8.  Security Considerations

   The YANG module defined in this memo is designed to be accessed via
   the NETCONF protocol [RFC6241].  The lowest NETCONF layer is the
   secure transport layer and the mandatory-to-implement secure
   transport is SSH [RFC6242].

   There are a number of data nodes defined in this YANG module which
   are writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)

   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

   /ipfix/observationPoint
      The configuration parameters in this subtree specify where packets
      are observed and by which Selection Processes they will be
      processed.  Write access to this subtree allows observing packets
      at arbitrary interfaces or linecards of the Monitoring Device and
      may thus lead to the export of sensitive traffic information.
   /ipfix/selectionProcess
      The configuration parameters in this subtree specify for which
      packets information will be reported in Packet Reports or Flow
      Records.  Write access to this subtree allows changing the subset
      of packets for which information will be reported and may thus
      lead to the export of sensitive traffic information.
   /ipfix/cache
      The configuration parameters in this subtree specify the fields
      included in Packet Reports or Flow Records.  Write access to this
      subtree allows adding fields which may contain sensitive traffic
      information, such as IP addresses or parts of the packet payload.
   /ipfix/exportingProcess
      The configuration parameters in this subtree specify to which
      Collectors Packet Reports or Flow Records are exported.  Write
      access to this subtree allows exporting potentially sensitive
      traffic information to illegitimate Collectors.  Furthermore, TLS/
      DTLS parameters can be changed, which may affect the mutual
      authentication between Exporters and Collectors as well as the
      encrypted transport of the data.
   /ipfix/collectingProcess
      The configuration parameters in this subtree may specify that
      collected Packet Reports and Flow Records are reexported to
      another Collector or written to a file.  Write access to this
      subtree potentially allows reexporting or storing the sensitive
      traffic information.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

   /ipfix/observationPoint
      Parameters in this subtree may be sensitive because they reveal
      information about the Monitoring Device itself and the network
      infrastructure.

   /ipfix/selectionProcess
      Parameters in this subtree may be sensitive because they reveal
      information about the Monitoring Device itself and the observed
      traffic.  For example, the counters packetsObserved and
      packetsDropped inferring the number of observed packets.
   /ipfix/cache
      Parameters in this subtree may be sensitive because they reveal
      information about the Monitoring Device itself and the observed
      traffic.  For example, the counters activeFlows and dataRecords
      allow inferring the number of measured Flows or packets.
   /ipfix/exportingProcess
      Parameters in this subtree may be sensitive because they reveal
      information about the network infrastructure and the outgoing
      IPFIX Transport Sessions.  For example, it discloses the IP
      addresses of Collectors as well as the deployed TLS/DTLS
      configuration, which may facilitate the interception of outgoing
      IPFIX Messages.
   /ipfix/collectingProcess
      Parameters in this subtree may be sensitive because they reveal
      information about the network infrastructure and the incoming
      IPFIX Transport Sessions.  For example, it discloses the IP
      addresses of Exporters as well as the deployed TLS/DTLS
      configuration, which may facilitate the interception of incoming
      IPFIX Messages.

9.  IANA Considerations

   This document registers a URI in the IETF XML registry [RFC3688].
   Following the format in RFC 3688, the following registration is
   requested.

      URI: urn:ietf:params:xml:ns:yang:ietf-ipfix-psamp
      Registrant Contact: The IPFIX WG of the IETF.
      XML: N/A, the requested URI is an XML namespace.

   This document registers a YANG module in the YANG Module Names
   registry [RFC6020].

      name: ietf-ipfix-psamp
      namespace: urn:ietf:params:xml:ns:yang:ietf-ipfix-psamp
      prefix: ipfix
      reference: RFC 6728

10.  Acknowledgements

   The authors thank Martin Bjorklund, Andy Bierman, and Ladislav Lhotka
   for helping specify the configuration data model in YANG, as well as
   Atsushi Kobayashi, Andrew Johnson, Lothar Braun, and Brian Trammell
   for their valuable reviews of this document.

11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5101]  Claise, B., "Specification of the IP Flow Information
              Export (IPFIX) Protocol for the Exchange of IP Traffic
              Flow Information", RFC 5101, January 2008.

   [RFC5102]  Quittek, J., Bryant, S., Claise, B., Aitken, P., and J.
              Meyer, "Information Model for IP Flow Information Export",
              RFC 5102, January 2008.

   [RFC5103]  Trammell, B. and E. Boschi, "Bidirectional Flow Export
              Using IP Flow Information Export (IPFIX)", RFC 5103,
              January 2008.

   [RFC5475]  Zseby, T., Molina, M., Duffield, N., Niccolini, S., and F.
              Raspall, "Sampling and Filtering Techniques for IP Packet
              Selection", RFC 5475, March 2009.

   [RFC5476]  Claise, B., Johnson, A., and J. Quittek, "Packet Sampling
              (PSAMP) Protocol Specifications", RFC 5476, March 2009.

   [RFC5477]  Dietz, T., Claise, B., Aitken, P., Dressler, F., and G.
              Carle, "Information Model for Packet Sampling Exports",
              RFC 5477, March 2009.

   [RFC6020]  Bjorklund, M., "YANG - A Data Modeling Language for the
              Network Configuration Protocol (NETCONF)", RFC 6020,
              October 2010.

   [RFC6021]  Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
              October 2010.

   [UML]      Object Management Group, "OMG Unified Modeling Language
              (OMG UML), Superstructure, V2.2", OMG formal/2009-02-02,
              February 2009.

   [IANA-IPFIX]
              IANA, "IP Flow Information Export (IPFIX) Entities",
              <http://www.iana.org/assignments/ipfix>.

11.2.  Informative References

   [RFC1141]  Mallory, T. and A. Kullberg, "Incremental updating of the
              Internet checksum", RFC 1141, January 1990.

   [RFC2863]  McCloghrie, K. and F. Kastenholz, "The Interfaces Group
              MIB", RFC 2863, June 2000.

   [RFC3280]  Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
              X.509 Public Key Infrastructure Certificate and
              Certificate Revocation List (CRL) Profile", RFC 3280,
              April 2002.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, May 2008.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

   [RFC3758]  Stewart, R., Ramalho, M., Xie, Q., Tuexen, M., and P.
              Conrad, "Stream Control Transmission Protocol (SCTP)
              Partial Reliability Extension", RFC 3758, May 2004.

   [RFC3871]  Jones, G., "Operational Security Requirements for Large
              Internet Service Provider (ISP) IP Network
              Infrastructure", RFC 3871, September 2004.

   [RFC3917]  Quittek, J., Zseby, T., Claise, B., and S. Zander,
              "Requirements for IP Flow Information Export (IPFIX)",
              RFC 3917, October 2004.

   [RFC4133]  Bierman, A. and K. McCloghrie, "Entity MIB (Version 3)",
              RFC 4133, August 2005.

   [RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security Version 1.2", RFC 6347, January 2012.

   [RFC6241]  Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
              Bierman, "Network Configuration Protocol (NETCONF)",
              RFC 6241, June 2011.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, June 2011.

   [RFC4960]  Stewart, R., "Stream Control Transmission Protocol",
              RFC 4960, September 2007.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.

   [RFC5470]  Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,
              "Architecture for IP Flow Information Export", RFC 5470,
              March 2009.

   [RFC5472]  Zseby, T., Boschi, E., Brownlee, N., and B. Claise, "IP
              Flow Information Export (IPFIX) Applicability", RFC 5472,
              March 2009.

   [RFC5473]  Boschi, E., Mark, L., and B. Claise, "Reducing Redundancy
              in IP Flow Information Export (IPFIX) and Packet Sampling
              (PSAMP) Reports", RFC 5473, March 2009.

   [RFC5474]  Duffield, N., Chiou, D., Claise, B., Greenberg, A.,
              Grossglauser, M., and J. Rexford, "A Framework for Packet
              Selection and Reporting", RFC 5474, March 2009.

   [RFC5610]  Boschi, E., Trammell, B., Mark, L., and T. Zseby,
              "Exporting Type Information for IP Flow Information Export
              (IPFIX) Information Elements", RFC 5610, July 2009.

   [RFC5655]  Trammell, B., Boschi, E., Mark, L., Zseby, T., and A.
              Wagner, "Specification of the IP Flow Information Export
              (IPFIX) File Format", RFC 5655, October 2009.

   [RFC6110]  Lhotka, L., "Mapping YANG to Document Schema Definition
              Languages and Validating NETCONF Content", RFC 6110,
              February 2011.

   [RFC6526]  Claise, B., Aitken, P., Johnson, A., and G. Muenz, "IP
              Flow Information Export (IPFIX) Per Stream Control
              Transmission Protocol (SCTP) Stream", RFC 6526,
              March 2012.

   [RFC6615]  Dietz, T., Kobayashi, A., Claise, B., and G. Muenz,
              "Definitions of Managed Objects for IP Flow Information
              Export", RFC 6615, June 2012.

   [W3C.REC-xml-20081126]
              Sperberg-McQueen, C., Yergeau, F., Bray, T., Paoli, J.,
              and E. Maler, "Extensible Markup Language (XML) 1.0 (Fifth
              Edition)", World Wide Web Consortium Recommendation
              REC-xml-20081126, November 2008,
              <http://www.w3.org/TR/2008/REC-xml-20081126>.

   [W3C.REC-xmlschema-0-20041028]
              Walmsley, P. and D. Fallside, "XML Schema Part 0: Primer
              Second Edition", World Wide Web Consortium Recommendation
              REC-xmlschema-0-20041028, October 2004,
              <http://www.w3.org/TR/2004/REC-xmlschema-0-20041028>.

   [RFC6727]  Dietz, T., Claise, B., and J. Quittek, "Definitions of
              Managed Objects for Packet Sampling", RFC 6727, October
              2012.

   [YANG-WEB]
              Bjoerklund, M., "YANG WebHome", March 2011,
              <http://www.yang-central.org/>.

   [IANA-ENTERPRISE-NUMBERS]
              IANA, "Private Enterprise Numbers",
              <http://www.iana.org/assignments/enterprise-numbers>.

Authors' Addresses

   Gerhard Muenz
   Technische Universitaet Muenchen
   Department of Informatics
   Chair for Network Architectures and Services (I8)
   Boltzmannstr. 3
   85748 Garching
   Germany

   EMail: muenz@net.in.tum.de
   URI:   http://www.net.in.tum.de/~muenz

   Benoit Claise
   Cisco Systems, Inc.
   De Kleetlaan 6a b1
   1831 Diegem
   Belgium

   Phone: +32 2 704 5622
   EMail: bclaise@cisco.com

   Paul Aitken
   Cisco Systems, Inc.
   96 Commercial Quay
   Commercial Street
   Edinburgh  EH6 6LX
   United Kingdom

   Phone: +44 131 561 3616
   EMail: paitken@cisco.com

 

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