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RFC 2769 - Routing Policy System Replication


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Network Working Group                                      C. Villamizar
Request for Comments: 2769                                 Avici Systems
Category: Standards Track                                C. Alaettinoglu
                                                             R. Govindan
                                                                     ISI
                                                                D. Meyer
                                                                   Cisco
                                                           February 2000

                   Routing Policy System Replication

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

   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 RFC 2119.

Abstract

   The RIPE database specifications and RPSL define languages used as
   the basis for representing information in a routing policy system.  A
   repository for routing policy system information is known as a
   routing registry.  A routing registry provides a means of exchanging
   information needed to address many issues of importance to the
   operation of the Internet.  The implementation and deployment of a
   routing policy system must maintain some degree of integrity to be of
   any use.  The Routing Policy System Security RFC [3] addresses the
   need to assure integrity of the data by proposing an authentication
   and authorization model.  This document addresses the need to
   distribute data over multiple repositories and delegate authority for
   data subsets to other repositories without compromising the
   authorization model established in Routing Policy System Security
   RFC.

Table of Contents

   1  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   2  Data Representation  . . . . . . . . . . . . . . . . . . . . .   4
   3  Authentication and Authorization . . . . . . . . . . . . . . .   5
   4  Repository Hierarchy . . . . . . . . . . . . . . . . . . . . .   6
   5  Additions to RPSL  . . . . . . . . . . . . . . . . . . . . . .   6
      5.1  repository object . . . . . . . . . . . . . . . . . . . .   7
      5.2  delegated attribute . . . . . . . . . . . . . . . . . . .   9
      5.3  integrity attribute . . . . . . . . . . . . . . . . . . .  10
   6  Interactions with a Repository or Mirror . . . . . . . . . . .  11
      6.1  Initial Transaction Submission  . . . . . . . . . . . . .  12
      6.2  Redistribution of Transactions  . . . . . . . . . . . . .  12
      6.3  Transaction Commit and Confirmation . . . . . . . . . . .  12
   7  Data Format Summaries, Transaction Encapsulation and Processing 13
      7.1  Transaction Submit and Confirm  . . . . . . . . . . . . .  13
      7.2  Redistribution of Transactions  . . . . . . . . . . . . .  16
      7.3  Redistribution Protocol Description . . . . . . . . . . .  16
           7.3.1 Explicitly Requesting Transactions  . . . . . . . .  21
           7.3.2 Heartbeat Processing  . . . . . . . . . . . . . . .  22
      7.4  Transaction Commit  . . . . . . . . . . . . . . . . . . .  23
      7.5  Database Snapshot . . . . . . . . . . . . . . . . . . . .  24
      7.6  Authenticating Operations . . . . . . . . . . . . . . . .  25
   A  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
      A.1  Initial Object Submission and Redistribution  . . . . . .  27
      A.2  Transaction Redistribution Encoding . . . . . . . . . . .  29
      A.3  Transaction Protocol Encoding . . . . . . . . . . . . . .  31
      A.4  Transaction Redistribution  . . . . . . . . . . . . . . .  32
   B  Technical Discussion . . . . . . . . . . . . . . . . . . . . .  35
      B.1  Server Processing . . . . . . . . . . . . . . . . . . . .  35
           B.1.1 getting connected . . . . . . . . . . . . . . . . .  35
           B.1.2 rolling transaction logs forward and back . . . . .  35
           B.1.3 committing or disposing of transactions . . . . . .  36
           B.1.4 dealing with concurrency  . . . . . . . . . . . . .  36
      B.2  Repository Mirroring for Redundancy . . . . . . . . . . .  36
      B.3  Trust Relationships . . . . . . . . . . . . . . . . . . .  37
      B.4  A Router as a Minimal Mirror  . . . . . . . . . . . . . .  38
      B.5  Dealing with Errors . . . . . . . . . . . . . . . . . . .  38
   C  Deployment Considerations  . . . . . . . . . . . . . . . . . .  39
   D  Privacy of Contact Information . . . . . . . . . . . . . . . .  39
   References  . . . . . . . . . . . . . . . . . . . . . . . . . . .  40
   Security Considerations . . . . . . . . . . . . . . . . . . . . .  41
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  41
   Full Copyright Statement  . . . . . . . . . . . . . . . . . . . .  42

1  Overview

   A routing registry must maintain some degree of integrity to be of
   any use.  The IRR is increasingly used for purposes that have a
   stronger requirement for data integrity and security.  There is also
   a desire to further decentralize the IRR. This document proposes a
   means of decentralizing the routing registry in a way that is
   consistent with the usage of the IRR and which avoids compromising
   data integrity and security even if the IRR is distributed among less
   trusted repositories.

   Two methods of authenticating the routing registry information have
   been proposed.

   authorization and authentication checks on transactions:  The
      integrity of the routing registry data is insured by repeating
      authorization checks as transactions are processed.  As
      transactions are flooded each remote registry has the option to
      repeat the authorization and authentication checks.  This scales
      with the total number of changes to the registry regardless of how
      many registries exist.  When querying, the integrity of the
      repository must be such that it can be trusted.  If an
      organization is unwilling to trust any of the available
      repositories or mirrors they have the option to run their own
      mirror and repeat authorization checks at that mirror site.
      Queries can then be directed to a mirror under their own
      administration which presumably can be trusted.

   signing routing registry objects:  An alternate which appears on the
      surface to be attractive is signing the objects themselves.
      Closer examination reveals that the approach of signing objects by
      itself is flawed and when used in addition to signing transactions
      and rechecking authorizations as changes are made adds nothing.
      In order for an insertion of critical objects such as inetnums and
      routes to be valid, authorization checks must be made which allow
      the insertion.  The objects on which those authorization checks
      are made may later change.  In order to later repeat the
      authorization checks the state of other objects, possibly in other
      repositories would have to be known.  If the repository were not
      trusted then the change history on the object would have to be
      traced back to the object's insertion.  If the repository were not
      trusted, the change history of any object that was depended upon
      for authorization would also have to be rechecked.  This trace
      back would have to go back to the epoch or at least to a point
      where only trusted objects were being relied upon for the
      authorizations.  If the depth of the search is at all limited,
      authorization could be falsified simply by exceeding the search
      depth with a chain of authorization references back to falsified

      objects.  This would be grossly inefficient.  Simply verifying
      that an object is signed provides no assurance that addition of
      the object addition was properly authorized.

   A minor distinction is made between a repository and a mirror.  A
   repository has responsibility for the initial authorization and
   authentication checks for transactions related to its local objects
   which are then flooded to adjacent repositories.  A mirror receives
   flooded transactions from remote repositories but is not the
   authoritative source for any objects.  From a protocol standpoint,
   repositories and mirrors appear identical in the flooding topology.

   Either a repository or a mirror may recheck all or a subset of
   transactions that are flooded to it.  A repository or mirror may
   elect not to recheck authorization and authentication on transactions
   received from a trusted adjacency on the grounds that the adjacent
   repository is trusted and would not have flooded the information
   unless authorization and authentication checks had been made.

   If it can be arranged that all adjacencies are trusted for a given
   mirror, then there is no need to implement the code to check
   authorization and authentication.  There is only a need to be able to
   check the signatures on the flooded transactions of the adjacent
   repository.  This is an important special case because it could allow
   a router to act as a mirror.  Only changes to the registry database
   would be received through flooding, which is a very low volume.  Only
   the signature of the adjacent mirror or repository would have to be
   checked.

2  Data Representation

   RPSL provides a complete description of the contents of a routing
   repository [1].  Many RPSL data objects remain unchanged from the
   RIPE, and RPSL references the RIPE-181 specification as recorded in
   RFC-1786 [2].  RPSL provides external data representation.  Data may
   be stored differently internal to a routing registry.  The integrity
   of the distributed registry data requires the use of the
   authorization and authentication additions to RPSL described in [3].

   Some additions to RPSL are needed to locate all of the repositories
   after having located one of them and to make certain parameters
   selectable on a per repository basis readily available.  These
   additions are described in Section 5.

   Some form of encapsulation must be used to exchange data.  The de-
   facto encapsulation has been that which the RIPE tools accept, a
   plain text file or plain text in the body of an RFC-822 formatted
   mail message with information needed for authentication derived from

   the mail headers.  Merit has slightly modified this using the PGP
   signed portion of a plain text file or PGP signed portion of the body
   of a mail message.

   The exchange that occurs during flooding differs from the initial
   submission.  In order to repeat the authorization checks the state of
   all repositories containing objects referenced by the authorization
   checks needs to be known.  To accomplish this a sequence number is
   associated with each transaction in a repository and the flooded
   transactions must contain the sequence number of each repository on
   which authorization of the transaction depends.

   In order to repeat authorization checks it must be possible to
   retrieve back revisions of objects.  How this is accomplished is a
   matter local to the implementation.  One method which is quite simple
   is to keep the traversal data structures to all current objects even
   if the state is deleted, keep the sequence number that the version of
   the object became effective and keep back links to prior versions of
   the objects.  Finding a prior version of an object involves looking
   back through the references until the sequence number of the version
   of the object is less than or equal to the sequence number being
   searched for.

   The existing very simple forms of encapsulation are adequate for the
   initial submission of a database transaction and should be retained
   as long as needed for backward compatibility.  A more robust
   encapsulation and submission protocol, with optional confirmation is
   defined in Section 6.1.  An encapsulation suitable for exchange of
   transaction between repositories is addressed in Section 6.  Query
   encapsulation and protocol is outside the scope of this document.

3  Authentication and Authorization

   Control must be exercised over who can make changes and what changes
   they can make.  The distinction of who vs what separates
   authentication from authorization.

   o  Authentication is the means to determine who is attempting to make
      a change.

   o  Authorization is the determination of whether a transaction
      passing a specific authentication check is allowed to perform a
      given operation.

   A submitted transaction contains a claimed identity.  Depending on
   the type of transaction, the authorization will depend on related
   objects.

   The "mnt-by", "mnt-routes", or "mnt-lower" attributes in those
   related objects reference "maintainer" objects.  Those maintainer
   objects contain "auth" attributes.  The auth attributes contain an
   authorization method and data which generally contains the claimed
   identity and some form of public encryption key used to authenticate
   the claim.

   Authentication is done on transactions.  Authentication should also
   be done between repositories to insure the integrity of the
   information exchange.  In order to comply with import, export, and
   use restrictions throughout the world no encryption capability is
   specified.  Transactions must not be encrypted because it may be
   illegal to use decryption software in some parts of the world.

4  Repository Hierarchy

   With multiple repositories, "repository" objects are needed to
   propagate the existence of new repositories and provide an automated
   means to determine the supported methods of access and other
   characteristics of the repository.  The repository object is
   described in Section 5.

   In each repository there should be a special repository object named
   ROOT. This should point to the root repository or to a higher level
   repository.  This is to allow queries to be directed to the local
   repository but refer to the full set of registries for resolution of
   hierarchically allocated objects.

   Each repository may have an "expire" attribute.  The expire attribute
   is used to determine if a repository must be updated before a local
   transaction that depends on it can proceed.

   The repository object also contains attributes describing the access
   methods and supported authentication methods of the repository.  The
   "query-address" attribute provides a host name and a port number used
   to direct queries.  The "response-auth-type" attribute provides the
   authentication types that may be used by the repository when
   responding to queries.  The "submit-address" attribute provides a
   host name and a port number used to submit objects to the repository.
   The "submit-auth-type" attribute provides the authentication types
   that may be used by the repository when responding to submissions.

5  Additions to RPSL

   There are very few additions to RPSL defined here.  The additions to
   RPSL are referred to as RPSL "objects".  They reside in the
   repository database and can be retrieved with ordinary queries.
   Objects consist of "attributes", which are name/value pairs.

   Attributes may be mandatory or optional.  They may be single or
   multiple.  One or more attributes may be part of a key field.  Some
   attributes may have the requirement of being unique.

   Most of the data formats described in this document are
   encapsulations used in transaction exchanges.  These are referred to
   as "meta-objects".  These "meta-objects", unlike RPSL "objects" do
   not reside in the database but some must be retained in a transaction
   log.  A similar format is used to represent "meta-objects".  They
   also consist of "attributes" which are name/value pairs.

   This section contains all of the additions to RPSL described in this
   document.  This section describes only RPSL objects.  Other sections
   described only meta-objects.

5.1  repository object

   A root repository must be agreed upon.  Ideally such a repository
   would contain only top level delegations and pointers to other
   repositories used in these delegations.  It would be wise to allow
   only cryptographically strong transactions in the root repository
   [3].

   The root repository contains references to other repositories.  An
   object of the following form identifies another repository.

     repository:         RIPE
     query-address:      whois://whois.ripe.net
     response-auth-type: PGPKEY-23F5CE35 # pointer to key-cert object
     response-auth-type: none
     remarks:            you can request rsa signature on queries
     remarks:            PGP required on submissions
     submit-address:     mailto://auto-dbm@ripe.net
     submit-address:     rps-query://whois.ripe.net:43
     submit-auth-type:   pgp-key, crypt-pw, mail-from
     remarks:            these are the authentication types supported
     mnt-by:             maint-ripe-db
     expire:             0000 04:00:00
     heartbeat-interval: 0000 01:00:00
     ...
     remarks:            admin and technical contact, etc
     source:             IANA

   The attributes of the repository object are listed below.

     repository      key  mandatory  single
     query-address        mandatory  multiple
     response-auth-type   mandatory  multiple
     submit-address       mandatory  multiple
     submit-auth-type     mandatory  multiple
     repository-cert      mandatory  multiple
     expire               mandatory  single
     heartbeat-interval   mandatory  single
     descr                optional   multiple
     remarks              optional   multiple
     admin-c              mandatory  multiple
     tech-c               mandatory  multiple
     notify               optional   multiple
     mnt-by               mandatory  multiple
     changed              mandatory  multiple
     source               mandatory  single

   In the above object type only a small number of the attribute types
   are new.  These are:

   repository  This attribute provides the name of the repository.  This
      is the key field for the object and is single and must be globally
      unique.  This is the same name used in the source attribute of all
      objects in that repository.

   query-address  This attribute provides a url for directing queries.
      "rps-query" or "whois" can be used as the protocol identifier.

   response-auth-type  This attribute provides an authentication type
      that may be used by the repository when responding to user
      queries.  Its syntax and semantics is same as the auth attribute
      of the maintainer class.

   submit-address  This attribute provides a url for submitting objects
      to the repository.

   submit-auth-type  This attribute provides the authentication types
      that are allowed by the repository for users when submitting
      registrations.

   repository-cert  This attribute provides a reference to a public key
      certificate in the form of an RPSL key-cert object.  This
      attribute can be multiple to allow the repository to use more than
      one method of signature.

   heartbeat-interval  Heartbeat meta-objects are sent by this
      repository at the rate of one heartbeat meta-object per the
      interval indicated.  The value of this attribute shall be
      expressed in the form "dddd hh:mm:ss", where the "dddd" represents
      days, "hh" represents hours, "mm" minutes and "ss" seconds.

   expire  If no heartbeat or new registrations are received from a
      repository for expire period, objects from this repository should
      be considered non-authoritative, and cannot be used for
      authorization purposes.  The value of this attribute shall be
      expressed in the form "dddd hh:mm:ss", where the "dddd" represents
      days, "hh" represents hours, "mm" minutes and "ss" seconds.  This
      value should be bigger than heartbeat-interval.

   Please note that the "heartbeat" meta-objects mentioned above, like
   other meta-objects described in this document are part of the
   protocol to exchange information but are not placed in the database
   itself.  See Section 7.3.2 for a description of the heartbeat meta-
   object.

   The remaining attributes in the repository object are defined in
   RPSL.

5.2  delegated attribute

   For many RPSL object types a particular entry should appear only in
   one repository.  These are the object types for which there is a
   natural hierarchy, "as-block", "aut-num", "inetnum", and "route".  In
   order to facilitate putting an object in another repository, a
   "delegated" attribute is added.

   delegated  The delegated attribute is allowed in any object type with
      a hierarchy.  This attribute indicates that further searches for
      object in the hierarchy must be made in one or more alternate
      repositories.  The current repository may be listed.  The ability
      to list more than one repository serves only to accommodate
      grandfathered objects (those created prior to using an
      authorization model).  The value of a delegated attribute is a
      list of repository names.

   If an object contains a "delegated" attribute, an exact key field
   match of the object may also be contained in each repository listed
   in the "delegated" attribute.  For the purpose of authorizing changes
   only the "mnt-by" in the object in the repository being modified is
   considered.

   The following is an example of the use of a "delegated" attribute.

     inetnum:        193.0.0.0 - 193.0.0.255
     delegated:      RIPE
     ...
     source:         IANA

   This inetnum simply delegates the storage of any more specific
   inetnum objects overlapping the stated range to the RIPE repository.
   An exact match of this inetnum may also exist in the RIPE repository
   to provide hooks for the attributes referencing maintainer objects.
   In this case, when adding objects to the RIPE repository, the "mnt-
   lower", "mnt-routes", and "mnt-by" fields in the IANA inetnum object
   will not be considered, instead the values in the RIPE copy will be
   used.

5.3  integrity attribute

   The "integrity" attribute can be contained in any RPSL object.  It is
   intended solely as a means to facilitate a transition period during
   which some data has been moved from repositories prior to the use of
   a strong authorization model and is therefore questionable, or when
   some repositories are not properly checking authorization.

   The "integrity" attribute may have the values "legacy", "no-auth",
   "auth-failed", or "authorized".  If absent, the integrity is
   considered to be "authorized".  The integrity values have the
   following meanings:

   legacy:  This data existed prior to the use of an adequate
      authorization model.  The data is highly suspect.

   no-auth:  This data was added to a repository during an initial
      transition use of an authorization model but authorization
      depended on other objects whose integrity was not "authorized".
      Such an addition is being allowed during the transition but would
      be disallowed later.

   auth-failed:  The authoritative repository is not checking
      authorization.  Had it been doing so, authorization would have
      failed.  This attribute may be added by a repository that is
      mirroring before placing the object in its local storage, or can
      add this attribute to an encapsulating meta-object used to further
      propagate the transaction.  If the failure to enforce
      authorization is intentional and part of a transition (for
      example, issuing warnings only), then the authoritative repository
      may add this attribute to the encapsulating meta-object used to
      further propagate the transaction.

   authorized:  Authorization checks were passed.  The maintainer
      contained a "referral-by" attribute, a form of authentication
      deemed adequate by the repository was used, and all objects that
      were needed for authorization were objects whose integrity was
      "authorized".

   Normally once an object is added to a repository another object
   cannot overwrite it unless authorized to do so by the maintainers
   referenced by the "mnt-by" attributes in the object itself.  If the
   integrity attribute is anything but "authorized", an object can be
   overwritten or deleted by any transaction that would have been a
   properly authorized addition had the object of lesser integrity not
   existed.

   During such a transition grandfathered data and data added without
   proper authorization becomes advisory until a properly authorized
   addition occurs.  After transition additions of this type would no
   longer be accepted.  Those objects already added without proper
   authorization would remain but would be marked as candidates for
   replacement.

6  Interactions with a Repository or Mirror

   This section presents an overview of the transaction distribution
   mechanisms.  The detailed format of the meta-objects for
   encapsulating and distributing transactions, and the rules for
   processing meta-objects are described in Section 7.  There are a few
   different types of interactions between routing repositories or
   mirrors.

   Initial submission of transactions:  Transactions may include
      additions, changes, and deletions.  A transaction may operate on
      more than one object and must be treated as an atomic operation.
      By definition initial submission of transactions is not applicable
      to a mirror.  Initial submission of transactions is described in
      Section 6.1.

   Redistribution of Transactions:  The primary purpose of the
      interactions between registries is the redistribution of
      transactions.  There are a number of ways to redistribute
      transactions.  This is discussed in Section 6.2.

   Queries:  Query interactions are outside the scope of this document.

   Transaction Commit and Confirmation:  Repositories may optionally
      implement a commit protocol and a completion indication that gives
      the submitter of a transaction a response that indicates that a

      transaction has been successful and will not be lost by a crash of
      the local repository.  A submitter may optionally request such a
      confirmation.  This is discussed in Section 6.3.

6.1  Initial Transaction Submission

   The simplest form of transaction submission is an object or set of
   objects submitted with RFC-822 email encapsulation.  This form is
   still supported for backwards compatibility.  A preferred form allows
   some meta-information to be included in the submission, such as a
   preferred form of confirmation.  Where either encapsulation is used,
   the submitter will connect to a host and port specified in the
   repository object.  This allows immediate confirmation.  If an email
   interface similar to the interface provided by the existing RIPE code
   is desired, then an external program can provide the email interface.

   The encapsulation of a transaction submission and response is
   described in detail in Section 7.

6.2  Redistribution of Transactions

   Redistribution of transactions can be accomplished using one of:

   1. A repository snapshot is a request for the complete contents of a
      given repository.  This is usually done when starting up a new
      repository or mirror or when recovering from a disaster, such as a
      disk crash.

   2. A transaction sequence exchange is a request for a specific set of
      transactions.  Often the request is for the most recent sequence
      number known to a mirror to the last transactions.  This is used
      in polling.

   3. Transaction flooding is accomplished through a unicast adjacency.

   This section describes the operations somewhat qualitatively.  Data
   formats and state diagrams are provided in Section 7.

6.3  Transaction Commit and Confirmation

   If a submission requires a strong confirmation of completion, or if a
   higher degree of protection against false positive confirmation is
   desired as a matter of repository policy, a commit may be performed.

   A commit request is a request from the repository processing an
   initial transaction submission to another repository to confirm that
   they have been able to advance the transaction sequence up to the

   sequence number immediately below the transaction in the request and
   are willing to accept the transaction in the request as a further
   advance in the sequence.  This indicates that either the
   authorization was rechecked by the responding repository and passed
   or that the responding repository trusts the requesting repository
   and has accepted the transaction.

   A commit request can be sent to more than one alternate repository.
   One commit completion response is sufficient to respond to the
   submitter with a positive confirmation that the transaction has been
   completed.  However, the repository or submitter may optionally
   require more than one.

7  Data Format Summaries, Transaction Encapsulation and Processing

   RIPE-181 [2] and RPSL [1] data is represented externally as ASCII
   text.  Objects consist of a set of attributes.  Attributes are
   name/value pairs.  A single attribute is represented as a single line
   with the name followed by a colon followed by whitespace characters
   (space, tab, or line continuation) and followed by the value.  Within
   a value all consecutive whitespace characters is equivalent to a
   single space.  Line continuation is supported by putting a white
   space or '+' character to the beginning of the continuation lines.
   An object is externally represented as a sequence of attributes.
   Objects are separated by blank lines.

   Protocol interactions between registries are activated by passing
   "meta objects".  Meta objects are not part of RPSL but conform to
   RPSL object representation.  They serve mostly as delimiters to the
   protocol messages or to carry the request for an operation.

7.1  Transaction Submit and Confirm

   The de-facto method for submitting database changes has been via
   email.  This method should be supported by an external application.
   Merit has added the pgp-from authentication method to the RADB
   (replaced by "pgpkey" in [4]), where the mail headers are essentially
   ignored and the body of the mail message must be PGP signed.

   This specification defines a different encapsulation for transaction
   submission.  When submitting a group of objects to a repository, a
   user MUST append to that group of objects, exactly one "timestamp"
   and one or more "signature" meta-objects, in that order.

   The "timestamp" meta-object contains a single attribute:

   timestamp  This attribute is mandatory and single-valued.  This
      attribute specifies the time at which the user submits the
      transaction to the repository.  The format of this attribute is
      "YYYYMMDD hh:mm:ss [+/-]xx:yy", where "YYYY" specifies the four
      digit year, "MM" represents the month, "DD" the date, "hh" the
      hour, "mm" the minutes, "ss" the seconds of the timestamp, and
      "xx" and "yy" represents the hours and minutes respectively that
      that timestamp is ahead or behind UTC.

   A repository may reject a transaction which does not include the
   "timestamp" meta-object.  The timestamp object is used to prevent
   replaying registrations.  How this is actually used is a local
   matter.  For example, a repository can accept a transaction only if
   the value of the timestamp attribute is greater than the timestamp
   attribute in the previous registration received from this user
   (maintainer), or the repository may only accept transactions with
   timestamps within its expire window.

   Each "signature" meta-object contains a single attribute:

   signature  This attribute is mandatory and single-valued.  This
      attribute, a block of free text, contains the signature
      corresponding to the authentication method used for the
      transaction.  When the authentication method is a cryptographic
      hash (as in PGP-based authentication), the signature must include
      all text up to (but not including) the last blank line before the
      first "signature" meta-object.

   A repository must reject a transaction that does not include any
   "signature" meta-object.

   The group of objects submitted by the user, together with the
   "timestamp" and "signature" meta-objects, constitute the "submitted
   text" of the transaction.

   The protocol used for submitting a transaction, and for receiving
   confirmation of locally committed transactions, is not specified in
   this document.  This protocol may define additional encapsulations
   around the submitted text.  The rest of this section gives an example
   of one such protocol.  Implementations are free to choose another
   encapsulation.

   The meta-objects "transaction-submit-begin" and "transaction-submit-
   end" delimit a transaction.  A transaction is handled as an atomic
   operation.  If any part of the transaction fails none of the changes
   take effect.  For this reason a transaction can only operate on a
   single database.

   A socket connection is used to request queries or submit
   transactions.  An email interface may be provided by an external
   program that connects to the socket.  A socket connection must use
   the "transaction-submit-begin" and "transaction-submit-end"
   delimiters but can request a legacy style confirmation.  Multiple
   transactions may be sent prior to the response for any single
   transaction.  Transactions may not complete in the order sent.

   The "transaction-submit-begin" meta-object may contain the following
   attributes.

   transaction-submit-begin  This attribute is mandatory and single.
      The value of the attribute contains name of the database and an
      identifier that must be unique over the course of the socket
      connection.

   response-auth-type  This attribute is optional and multiple.  The
      remainder of the line specifies an authentication type that would
      be acceptable in the response.  This is used to request a response
      cryptographically signed by the repository.

   transaction-confirm-type  This attribute is optional and single.  A
      confirmation type keyword must be provided.  Keywords are "none",
      "legacy", "normal", "commit".  The confirmation type can be
      followed by the option "verbose".

   The "transaction-submit-end meta-object consists of a single
   attribute by the same name.  It must contain the same database name
   and identifier as the corresponding "transaction-submit-begin"
   attribute.

   Unless the confirmation type is "none" a confirmation is sent.  If
   the confirmation type is "legacy", then an email message of the form
   currently sent by the RIPE database code will be returned on the
   socket (suitable for submission to the sendmail program).

   A "normal" confirmation does not require completion of the commit
   protocol.  A "commit" confirmation does.  A "verbose" confirmation
   may contain additional detail.

   A transaction confirmation is returned as a "transaction-confirm"
   meta-object.  The "transaction-confirm" meta-object may have the
   following attributes.

   transaction-confirm  This attribute is mandatory and single.  It
      contains the database name and identifier associated with the
      transaction.

   confirmed-operation  This attribute is optional and multiple.  It
      contains one of the keywords "add", "delete" or "modify" followed
      by the object type and key fields of the object operated on.

   commit-status  This attribute is mandatory and single.  It contains
      one of the keywords "succeeded, "error", or "held".  The "error"
      keyword may be followed by an optional text string.  The "held"
      keyword is returned when a repository containing a dependent
      object for authorization has expired.

7.2  Redistribution of Transactions

   In order to redistribute transactions, each repository maintains a
   TCP connection with one or more other repositories.  After locally
   committing a submitted transaction, a repository assigns a sequence
   number to the transaction, signs and encapsulates the transaction,
   and then sends one copy to each neighboring (or "peer") repository.
   In turn, each repository authenticates the transaction (as described
   in Section 7.6), may re-sign the transaction and redistributes the
   transaction to its neighbors.  We use the term "originating
   repository" to distinguish the repository that redistributes a
   locally submitted transaction.

   This document also specifies two other methods for redistributing
   transactions to other repositories:  a database snapshot format used
   for initializing a new registry, and a polling technique used by
   mirrors.

   In this section, we first describe how a repository may encapsulate
   the submitted text of a transaction.  We then describe the protocol
   for flooding transactions or polling for transactions, and the
   database snapshot contents and format.

7.3  Redistribution Protocol Description

   The originating repository must first authenticate a submitted
   transaction using methods described in [3].

   Before redistributing a transaction, the originating repository must
   encapsulate the submitted text of the transaction with several meta-
   objects, which are described below.

   The originating repository must prepend the submitted text with
   exactly one "transaction-label" meta-object.  This meta-object
   contains the following attributes:

   transaction-label  This attribute is mandatory and single.  The value
      of this attribute conforms to the syntax of an RPSL word, and
      represents a globally unique identifier for the database to which
      this transaction is added.

   sequence  This attribute is mandatory and single.  The value of this
      attribute is an RPSL integer specifying the sequence number
      assigned by the originating repository to the transaction.
      Successive transactions distributed by the same originating
      repository have successive sequence numbers.  The first
      transaction originated by a registry is assigned a sequence number
      1.  Each repository must use sequence numbers drawn from a range
      at least as large as 64 bit unsigned integers.

   timestamp  This attribute is mandatory and single-valued.  This
      attribute specifies the time at which the originating repository
      encapsulates the submitted text.  The format of this attribute is
      "YYYYMMDD hh:mm:ss [+/-]xx:yy", where "YYYY" specifies the four
      digit year, "MM" represents the month, "DD" the date, "hh" the
      hour, "mm" the minutes, "ss" the seconds of the timestamp, and
      "xx" and "yy" represents the hours and minutes respectively that
      that timestamp is ahead or behind UTC.

   integrity  This attribute is optional and single-valued.  It may have
      the values "legacy", "no-auth", "auth-failed", or "authorized".
      If absent, the integrity is considered to be "authorized".

   The originating repository may append to the submitted text one or
   more "auth-dependency" meta-objects.  These meta-objects are used to
   indicate which other repositories' objects were used by the
   originating registry to authenticate the submitted text.  The "auth-
   dependency" meta-objects should be ordered from the most preferred
   repository to the least preferred repository.  This order is used by
   a remote repository to tie break between the multiple registrations
   of an object with the same level of integrity.  The "auth-dependency"
   meta-object contains the following attributes:

   auth-dependency  This attribute mandatory and single-valued.  It
      equals a repository name from which an object is used to
      authorize/authenticate this transaction.

   sequence  This attribute mandatory and single-valued.  It equals the
      transaction sequence number of the dependent repository known at
      the originating repository at the time of processing this
      transaction.

   timestamp  This attribute mandatory and single-valued.  It equals the
      timestamp of the dependent repository known at the originating
      repository at the time of processing this transaction.

   If the originating repository needs to modify submitted objects in a
   way that the remote repositories can not re-create, it can append an
   "override-objects" meta-object followed by the modified versions of
   these objects.  An example modification can be auto assignment of NIC
   handles.  The "override-objects" meta-object contains the following
   attributes:

   override-objects  A free text remark.

   Other repositories may or may not honor override requests, or limit
   the kinds of overrides they allow.

   Following this, the originating repository must append exactly one
   "repository-signature" meta-object.  The "repository-signature"
   meta-object contains the following attributes:

   repository-signature  This attribute is mandatory and single-valued.
      It contains the name of the repository.

   integrity  This attribute is optional and single-valued.  It may have
      the values "legacy", "no-auth", "auth-failed", or "authorized".
      If absent, the value is same as the value in the transaction-
      label.  If a different value is used, the value here takes
      precedence.

   signature  This attribute is optional and single-valued.  This
      attribute, a block of free text, contains the repository's
      signature using the key in the repository-cert attribute of the
      repository object.  When the authentication method is a
      cryptographic hash (as in PGP-based authentication), the signature
      must include all text upto (but not including) this attribute.
      That is, the "repository-signature" and "integrity" attributes of
      this object are included.  This attribute is optional since
      cryptographic authentication may not be available everywhere.
      However, its use where it is available is highly recommended.

   A repository must reject a redistributed transaction that does not
   include any "repository-signature" meta-object.

   The transaction-label, the submitted text, the dependency objects,
   the override-objects, the overridden objects, and the repository's
   signature together constitute what we call the "redistributed text".

   In preparation for redistributing the transaction to other
   repositories, the originating repository must perform the following
   protocol encapsulation.  This protocol encapsulation may involve
   transforming the redistributed text according to one of the
   "transfer-method"s described below.

   The transformed redistributed text is first prepended with exactly
   one "transaction-begin" meta-object.  One newline character separates
   this meta-object from the redistributed text.  This meta-object has
   the following attributes:

   transaction-begin  This attribute is mandatory and single.  The value
      of this attribute is the length, in bytes, of the transformed
      redistributed text.

   transfer-method  This attribute is optional and single-valued.  Its
      value is either "gzip", or "plain".  The value of the attribute
      describes the kind of text encoding that the repository has
      performed on the redistributed text.  If this attribute is not
      specified, its value is assumed to be "plain".  An implementation
      must be capable of encoding and decoding both of these types.

   The "transaction-begin" meta-object and the transformed redistributed
   text constitute what we call the "transmitted text".  The originating
   repository may distribute the transmitted text to one or more peer
   repositories.

   When a repository receives the transmitted text of a transaction, it
   must perform the following steps.  After performing the following
   steps, a transaction may be marked successful or failed.

   1. It must decapsulate the "transaction-begin" meta-object, then
      decode the original redistributed text according to the value of
      the transfer-method attribute specified in the "transaction-begin"
      meta-object.

   2. It should then extract the "transaction-label" meta-object from
      the transmitted text.  If this transaction has already been
      processed, or is currently being held, the repository must
      silently discard this incarnation of the same transaction.

   3. It should verify that the signature of the originating repository
      matches the first "repository-signature" meta-object in the
      redistributed text following the "auth-dependency" meta-objects.

   4. If not all previous (i.e., those with a lower sequence number)
      transactions from the same repository have been received or
      completely processed, the repository must "hold" this transaction.

   5. It may check whether any subsequent "repository-signature" meta-
      objects were appended by a trusted repository.  If so, this
      indicates that the trusted repository verified the transaction's
      integrity and marked its conclusion in the integrity attribute of
      this object.  The repository may verify the trusted repositories
      signature and also mark the transaction with the same integrity,
      and skip the remaining steps.

   6. It should verify the syntactic correctness of the transaction.  An
      implementation may allow configurable levels of syntactic
      conformance with RPSL [1].  This enables RPSL extensions to be
      incrementally deployed in the distributed registry scheme.

   7. The repository must authorize and authenticate this transaction.
      To do this, it may need to reference objects and transactions from
      other repositories.  If these objects are not available, the
      repository must "hold" this transaction as described in Section
      7.6, until it can be authorized and authenticated later.  In order
      to verify authorization/authentication of this transaction, the
      repository must not use an object from a repository not mentioned
      in an "auth-dependency" meta-object.  The repository should also
      only use the latest objects (by rolling back to earlier versions
      if necessary) which are within the transaction sequence numbers of
      the "auth-dependency" meta-objects.

   A non-originating repository must redistribute a failed transaction
   in order not to cause a gap in the sequence.  (If the transaction was
   to fail at the originating registry, it would simply not be assigned
   a sequence number).

   To the redistributed text of a transaction, a repository may append
   another "repository-signature" meta-object.  This indicates that the
   repository has verified the transaction's integrity and marked it in
   the "integrity" attribute of this object.  The signature covers the
   new redistributed text from (and including) the transaction-label
   object to this object's signature attribute (including the
   "repository-signature" and "integrity" attributes of this object, but
   excluding the "signature" attribute).  The original redistributed
   text, together with the new "repository-signature" meta-object
   constitutes the modified redistributed text.

   To redistribute a successful or failed transaction, the repository
   must encapsulate the (original or modified) redistributed text with a
   "transaction-begin" object.  This step is essentially the same as

   that performed by the originating repository (except that the
   repository is free to use a different "transfer-method" from the one
   that was in the received transaction.

7.3.1  Explicitly Requesting Transactions

   A repository may also explicitly request one or more transactions
   belonging to a specified originating repository.  This is useful for
   catching up after a repository has been off-line for a period of
   time.  It is also useful for mirrors which intermittently poll a
   repository for recently received transactions.

   To request a range of transactions from a peer, a repository must
   send a "transaction-request" meta-object to the peer.  A
   "transaction-request" meta-object may contain the following
   attributes:

   transaction-request  This attribute is mandatory and single.  It
      contains the name of the database whose transactions are being
      requested.

   sequence-begin  This attribute is optional and single.  It contains
      the sequence number of the first transaction being requested.

   sequence-end  This attribute is optional and single.  It contains the
      sequence number of the last transaction being requested.

   Upon receiving a "transaction-request" object, a repository performs
   the following actions.  If the "sequence-begin" attribute is not
   specified, the repository assumes the request first sequence number
   to be 1.  The last sequence number is the lesser of the value of the
   "sequence-end" attributed and the highest completed transaction in
   the corresponding database.  The repository then, in order, transmits
   the requested range of transactions.  Each transaction is prepared
   exactly according to the rules for redistribution specified in
   Section 7.3.

   After transmitting all the transactions, the peer repository must
   send a "transaction-response" meta-object.  This meta-object has the
   following attributes:

   transaction-response  This attribute is mandatory and single.  It
      contains the name of the database whose transactions are were
      requested.

   sequence-begin  This attribute is optional and mandatory.  It
      contains the value of the "sequence-begin" attribute in the
      original request.  It is omitted if the corresponding attribute
      was not specified in the original request.

   sequence-end  This attribute is optional and mandatory.  It contains
      the value of the "sequence-end" attribute in the original request.
      It is omitted if the corresponding attribute was not specified in
      the original request.

   After receiving a "transaction-response" meta-object, a repository
   may tear down the TCP connection to its peer.  This is useful for
   mirrors that intermittently resynchronize transactions with a
   repository.  If the TCP connection stays open, repositories exchange
   subsequent transactions according to the redistribution mechanism
   specified in Section  7.3.  While a repository is responding to a
   transaction-request, it MAY forward heartbeats and other transactions
   from the requested repository towards the requestor.

7.3.2  Heartbeat Processing

   Each repository that has originated at least one transaction must
   periodically send a "heartbeat" meta-object.  The interval between
   two successive transmissions of this meta-object is configurable but
   must be less than 1 day.  This meta-object serves to indicate the
   liveness of a particular repository.  The repository liveness
   determines how long transactions are held (See Section 7.6).

   The "heartbeat" meta-object contains the following attributes:

   heartbeat  This attribute is mandatory and single.  It contains the
      name of the repository which originates this meta-object.

   sequence  This attribute is mandatory and single.  It contains the
      highest transaction sequence number that has been assigned by the
      repository.

   timestamp  This attribute is mandatory and single.  It contains the
      time at which this meta-object was generated.  The format of this
      attribute is "YYYYMMDD hh:mm:ss [+/-]xx:yy", where "YYYY"
      specifies the four digit year, "MM" represents the month, "DD" the
      date, "hh" the hour, "mm" the minutes, "ss" the seconds of the
      timestamp, and "xx" and "yy" represents the hours and minutes
      respectively that that timestamp is ahead or behind UTC.

   Upon receiving a heartbeat meta-object, a repository must first check
   the timestamp of the latest previously received heartbeat message.
   If that timestamp exceeds the timestamp in the received heartbeat

   message, the repository must silently discard the heartbeat message.
   Otherwise, it must record the timestamp and sequence number in the
   heartbeat message, and redistribute the heartbeat message, without
   modification, to each of its peer repositories.

   If the heartbeat message is from a repository previously unknown to
   the recipient, the recipient may send a "transaction-request" to one
   or more of its peers to obtain all transactions belonging to the
   corresponding database.  If the heartbeat message contains a sequence
   number higher than the highest sequence number processed by the
   recipient, the recipient may send a "transaction-request" to one or
   more of its peers to obtain all transactions belonging to the
   corresponding database.

7.4  Transaction Commit

   Submitters may require stronger confirmation of commit for their
   transactions (Section 6.3).  This section describes a simple
   request-response protocol by which a repository may provide this
   stronger confirmation, by verifying if one or more other repositories
   have committed the transaction.  Implementation of this request-
   response protocol is optional.

   After it has redistributed a transaction, the originating repository
   may request a commit confirmation from one or more peer repositories
   by sending to them a "commit-request" meta-object.  The "commit-
   request" contains two attributes:

   commit-request  This attribute is mandatory and single.  It contains
      the name of the database for whom a commit confirmation is being
      requested.

   sequence  This attribute is mandatory and single.  It contains the
      transaction sequence number for which a commit confirmation is
      being requested.

   A repository that receives a "commit-request" must not redistribute
   the request.  It must delay the response until the corresponding
   transaction has been processed.  For this reason, the repository must
   keep state about pending commit requests.  It should discard this
   state if the connection to the requester is lost before the response
   is sent.  In that event, it is the responsibility of the requester to
   resend the request.

   Once a transaction has been processed (Section 7.3), a repository
   must check to see if there exists any pending commit request for the
   transaction.  If so, it must send a "commit-response" meta-object to
   the requester.  This meta-object has three attributes:

   commit-response  This attribute is mandatory and single.  It contains
      the name of the database for whom a commit response is being sent.

   sequence  This attribute is mandatory and single.  It contains the
      transaction sequence number for which a commit response is being
      sent.

   commit-status  This attribute is mandatory and single.  It contains
      one of the keywords "held", "error", or "succeeded".  The "error"
      keyword may be followed by an optional text string.  The "held"
      keyword is returned when a repository containing a dependent
      object for authorization has expired.

7.5  Database Snapshot

   A database snapshot provides a complete copy of a database.  It is
   intended only for repository initialization or disaster recovery.  A
   database snapshot is an out of band mechanism.  A set of files are
   created periodically at the source repository.  These files are then
   transferred to the requestor out of band (e.g.  ftp transfer).  The
   objects in these files are then registered locally.

   A snapshot of repository X contains the following set of files:

   X.db  This file contains the RPSL objects of repository X, separated
      by blank lines.  In addition to the RPSL objects and blank lines,
      comment lines can be present.  Comment lines start with the
      character '#'.  The comment lines are ignored.  The file X.db ends
      in a special comment line "# eof".

   X.<class>.db  This optional file if present contains the RPSL objects
      in X.db that are of class <class>.  The format of the file is same
      as that of X.db.

   X.transaction-label  This file contains a transaction-label object
      that records the timestamp and the latest sequence number of the
      repository at the time of the snapshot.

   Each of these files can be optionally compressed uzing gzip.  This is
   signified by appending the suffix .gz to the file name.  Each of
   these files can optionally be PGP signed.  In this case, the detached
   signature with ASCII armoring and platform-independent text mode is
   stored in a file whose name is constructed by appending .sig to the
   file name of the file being signed.

   In order to construct a repository's contents from a snapshot, a
   repository downloads these files.  After uncompressing and checking
   signatures, the repository records these objects in its database.  No

   RPS authorization/authentication is done on these objects.  The
   transaction-label object provides the seed for the replication
   protocol to receive the follow on transactions from this repository.
   Hence, it is not crucial to download an up to the minute snapshot.

   After successfully playing a snapshot, it is possible that a
   repository may receive a transaction from a third repository that has
   a dependency on an earlier version of one of the objects in the
   snapshot.  This can only happen within the expire period of the
   repository being downloaded, plus any possible network partition
   period.  This dependency is only important if the repository wants to
   re-verify RPS authorization/authentication.  There are three allowed
   alternatives in this case.  The simplest alternative is for the
   repository to accept the transaction and mark it with integrity "no-
   auth".  The second choice is to only peer with trusted repositories
   during this time period, and accept the transaction with the same
   integrity as the trusted repository (possibly as "authorized").  The
   most preferred alternative is not to download an up to the minute
   snapshot, but to download an older snapshot, at minimum twice the
   repositories expire time, in practice few days older.  Upon replaying
   an older snapshot, the replication protocol will fetch the more
   current transactions from this repository.  Together they provide the
   necessary versions of objects to re-verify rps
   authorization/authentication.

7.6  Authenticating Operations

   The "signature" and "repository-signature" meta-objects represent
   signatures.  Where multiple of these objects are present, the
   signatures should be over the original contents, not over other
   signatures.  This allows signatures to be checked in any order.

   A maintainer can also sign a transaction using several authentication
   methods (some of which may be available in some repositories only).

   In the case of PGP, implementations should allow the signatures of
   the "signature" and "repository-signature" meta-objects to be either
   the detached signatures produced by PGP or regular signatures
   produced by PGP. In either case, ASCII armoring and platform-
   independent text mode should be used.

   Note that the RPSL objects themselves are not signed but the entire
   transaction body is signed.  When exchanging transactions among
   registries, the meta-objects (e.g.  "auth-dependency") prior to the
   first "repository-signature" meta object in the redistributed text
   are also signed over.

   Transactions must remain intact, including the signatures, even if an
   authentication method provided by the submitter is not used by a
   repository handling the message.  An originating repository may chose
   to remove clear text passwords signatures from a transaction, and
   replace it with the keyword "clear-text-passwd" followed by the
   maintainer's id.

     signature: clear-text-passwd <maintainer-name>

   Note that this does not make the system less secure since clear text
   password is an indication of total trust to the originating
   repository by the maintainer.

   A repository may sign a transaction that it verified.  If at any
   point the signature of a trusted repository is encountered, no
   further authorization or authentication is needed.

A  Examples

   RPSL provides an external representation of RPSL objects and
   attributes.  An attribute is a name/value pair.  RPSL is line
   oriented.  Line continuation is supported, however most attributes
   fit on a single line.  The attribute name is followed by a colon,
   then any amount of whitespace, then the attribute value.  An example
   of the ASCII representation of an RPSL attribute is the following:

       route:     140.222.0.0/16

   An RPSL object is a set of attributes.  Objects are separated from
   each other by one or more blank lines.  An example of a complete RPSL
   object follows:

       route:         140.222.0.0/16
       descr:         ANS Communications
       origin:        AS1673
       member-of:     RS-ANSOSPFAGGREGATE
       mnt-by:        ANS
       changed:       tck@ans.net 19980115
       source:        ANS

A.1  Initial Object Submission and Redistribution

   Figure 1 outlines the steps involved in submitting an object and the
   initial redistribution from the authoritative registry to its flooding
   peers.

   If the authorization check requires objects from other repositories,
   then the sequence numbers of the local copies of those databases is
   required for mirrors to recheck the authorization.

   To simply resubmit the object from the prior example, the submitter or
   a client application program acting on the submitter's behalf must
   submit a transaction.  The legacy method was to send PGP signed email.
   The preferred method is for an interactive program to encapsulate a
   request between "transaction-submit-begin" and
   "transaction-submit-end" meta-objects and encapsulate that as a
   signed block as in the following example:

    +--------------+
    |  Transaction |
    |  signed by   |
    |  submitter   |
    +--------------+
           |
           |  1
           v
    +---------------------+  2
    |  Primary repository |---->+----------+
    |  identified by      |     | database |
    |  RPSL source        |<----+----------+
    +---------------------+  3
           |
           |  4
           v
    +----------------+
    |  Redistributed |
    |  transaction   |
    +----------------+

    1.  submit object
    2.  authorization check
    3.  sequence needed for authorization
    4.  redistribute

   Figure 1:  Initial Object Submission and Redistribution

    transaction-submit-begin:  ANS 1
    response-auth-type:        PGP
    transaction-confirm-type:  normal

    route:         140.222.0.0/16
    descr:         ANS Communications
    origin:        AS1673
    member-of:     RS-ANSOSPFAGGREGATE
    mnt-by:        ANS
    changed:       curtis@ans.net 19990401
    source:        ANS

    timestamp: 19990401 10:30:00 +08:00

    signature:
    + -----BEGIN PGP SIGNATURE-----
    + Version: PGP for Personal Privacy 5.0
    + MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
    +
    + iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
    + Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
    + Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
    + PGBIEN3/NlM=
    + =c93c
    + -----END PGP SIGNATURE-----

    transaction-submit-end:    ANS 1

   The signature covers the everything after the first blank line after
   the "transaction-submit-begin" object to the last blank line before
   the "signature" meta-object.  If multiple signatures are needed, it
   would be quite easy to email this block and ask the other party to
   add a signature-block and return or submit the transaction.  Because
   of delay in obtaining multiple signatures the accuracy of the
   "timestamp" cannot be strictly enforced.  Enforcing accuracy to
   within the "expire" time of the database might be a reasonable
   compromise.  The tradeoff is between convenience, allowing a longer
   time to obtain multiple signatures, and increased time of exposure to
   replay attack.

   The ANS repository would look at its local database and make
   authorization checks.  If the authorization passes, then the sequence
   number of any other database needed for the authorization is
   obtained.

   If this operation was successful, then a confirmation would be
   returned.  The confirmation would be of the form:

    transaction-confirm:  ANS 1
    confirmed-operation:  change route 140.222.0.0/16 AS1673
    commit-status:        commit
    timestamp:            19990401 10:30:10 +05:00

A.2  Transaction Redistribution Encoding

   Having passed the authorization check the transaction is given a
   sequence number and stored in the local transaction log and is then
   flooded.  The meta-object flooded to another database would be signed
   by the repository and would be of the following form:

    transaction-label: ANS
    sequence: 6666
    timestamp: 19990401 13:30:10 +05:00
    integrity: authorized

    route:         140.222.0.0/16
    descr:         ANS Communications
    origin:        AS1673
    member-of:     RS-ANSOSPFAGGREGATE
    mnt-by:        ANS
    changed:       curtis@ans.net 19990401
    source:        ANS

    timestamp: 19990401 10:30:00 +08:00

    signature:
    + -----BEGIN PGP SIGNATURE-----
    + Version: PGP for Personal Privacy 5.0
    + MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
    +
    + iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
    + Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
    + Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
    + PGBIEN3/NlM=
    + =c93c
    + -----END PGP SIGNATURE-----

    auth-dependency: ARIN
    sequence: 555
    timestamp: 19990401 13:30:08 +05:00

    auth-dependency: RADB
    sequence: 4567
    timestamp: 19990401 13:27:54 +05:00

    repository-signature: ANS
    signature:
    + -----BEGIN PGP SIGNATURE-----
    + Version: PGP for Personal Privacy 5.0
    + MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
    +
    + iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
    + Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
    + Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
    + PGBIEN3/NlM=
    + =c93c
    + -----END PGP SIGNATURE-----

   Note that the repository-signature above is a detached signature for
   another file and is illustrative only.  The repository-signature
   covers from the "transaction-label" meta-object (including) to the
   last blank line before the first "repository-signature" meta-object
   (excluding the last blank line and the "repository-signature"
   object).

A.3  Transaction Protocol Encoding

    transaction-begin: 1276
    transfer-method: plain

    transaction-label: ANS
    sequence: 6666
    timestamp: 19990401 13:30:10 +05:00
    integrity: authorized

    route:         140.222.0.0/16
    descr:         ANS Communications
    origin:        AS1673
    member-of:     RS-ANSOSPFAGGREGATE
    mnt-by:        ANS
    changed:       curtis@ans.net 19990401
    source:        ANS

    timestamp: 19990401 10:30:00 +08:00

    signature:
    + -----BEGIN PGP SIGNATURE-----
    + Version: PGP for Personal Privacy 5.0
    + MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
    +
    + iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
    + Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
    + Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
    + PGBIEN3/NlM=
    + =c93c
    + -----END PGP SIGNATURE-----

    auth-dependency: ARIN
    sequence: 555
    timestamp: 19990401 13:30:08 +05:00

    auth-dependency: RADB
    sequence: 4567
    timestamp: 19990401 13:27:54 +05:00

    repository-signature: ANS
    signature:
    + -----BEGIN PGP SIGNATURE-----
    + Version: PGP for Personal Privacy 5.0
    + MessageID: UZi4b7kjlzP7rb72pATPywPxYfQj4gXI
    +
    + iQCVAwUANsrwkP/OhQ1cphB9AQFOvwP/Ts8qn3FRRLQQHKmQGzy2IxOTiF0QXB4U
    + Xzb3gEvfeg8NWhAI32zBw/D6FjkEw7P6wDFDeok52A1SA/xdP5wYE8heWQmMJQLX
    + Avf8W49d3CF3qzh59UC0ALtA5BjI3r37ubzTf3mgtw+ONqVJ5+lB5upWbqKN9zqv
    + PGBIEN3/NlM=
    + =c93c
    + -----END PGP SIGNATURE-----

   Before the transaction is sent to a peer, the repository prepends a
   "transaction-begin" meta-object.  The value of the "transaction-
   begin" attribute is the number of octets in the transaction, not
   counting the "transaction-begin" meta-object and the first blank line
   after it.

   Separating transaction-begin and transaction-label objects enables
   different encodings at different flooding peerings.

A.4  Transaction Redistribution

   The last step in Figure 1 was redistributing the submitter's
   transaction through flooding (or later through polling).  Figure 2
   illustrates the further redistribution of the transaction.

   If the authorization check was repeated, the mirror may optionally
   add a repository-signature before passing the transaction any
   further.  A "signature" can be added within that block.  The previous
   signatures should not be signed.

   Figure 3 illustrates the special case referred to as a "lightweight
   mirror".  This is specifically intended for routers.

   The lightweight mirror must trust the mirror from which it gets a
   feed.  This is a safe assumption if the two are under the same
   administration (the mirror providing the feed is a host owned by the
   same ISP who owns the routers).  The lightweight mirror simply checks
   the signature of the adjacent repository to insure data integrity.

    +----------------+
    |  Redistributed |
    |  transaction   |
    +----------------+
           |
           |  1
           v
    +--------------------+  2
    |                    |---->+----------+
    |  Mirror repository |     | database |
    |                    |<----+----------+
    +--------------------+  3
           |
           |  4
           v
    +------------------+
    |+----------------+|
    ||  Redistributed ||
    ||  transaction   ||
    |+----------------+|
    |  Optional        |
    |  signature       |
    +------------------+

    1.  redistribute transaction
    2.  recheck authorization against full DB at the
        time of the transaction using sequence numbers
    3.  authorization pass/fail
    4.  optionally sign then redistribute

   Figure 2:  Further Transaction Redistribution

    +----------------+
    |  Redistributed |
    |  transaction   |
    +----------------+
           |  1
           v
    +--------------------+  2
    |                    |---->+----------+
    |  Mirror repository |     | database |
    |                    |<----+----------+
    +--------------------+  3
           |  4
           v
    +----------------+
    |  Redistributed |
    |  transaction   |
    +----------------+
           |  5
           v
    +--------------------+
    |  Lightweight       |  6  +----------+
    |  Mirror repository |---->| database |
    |  (router?)         |     +----------+
    +--------------------+

    1.  redistribute transaction
    2.  recheck authorization against full DB at the
        time of the transaction using sequence numbers
    3.  authorization pass/fail
    4.  sign and redistribute
    5.  just check mirror signature
    6.  apply change with no authorization check

   Figure 3:  Redistribution to Lightweight Mirrors

B  Technical Discussion

B.1  Server Processing

   This document does not mandate any particular software design,
   programming language choice, or underlying database or underlying
   operating system.  Examples are given solely for illustrative
   purposes.

B.1.1  getting connected

   There are two primary methods of communicating with a repository
   server.  E-mail can be sent to the server.  This method may be
   deprecated but at least needs to be supported during transition.  The
   second method is preferred, connect directly to a TCP socket.

   Traditionally the whois service is supported for simple queries.  It
   might be wise to retain the whois port connection solely for simple
   queries and use a second port not in the reserved number space for
   all other operations including queries except those queries using the
   whois unstructured single line query format.

   There are two styles of handling connection initiation is the
   dedicated daemon, in the style of BSD sendmail, or launching through
   a general purpose daemon such as BSD inetd.  E-mail is normally
   handled sequentially and can be handled by a front end program which
   will make the connection to a socket in the process as acting as a
   mail delivery agent.

B.1.2  rolling transaction logs forward and back

   There is a need to be able to easily look back at previous states of
   any database in order to repeat authorization checks at the time of a
   transaction.  This is difficult to do with the RIPE database
   implementation, which uses a sequentially written ASCII file and a
   set of Berkeley DB maintained index files for traversal.  At the very
   minimum, the way in which deletes or replacements are implemented
   would need to be altered.

   In order to easily support a view back at prior versions of objects,
   the sequence number of the transaction at which each object was
   entered would need to be kept with the object.  A pointer would be
   needed back to the previous state of the object.  A deletion would
   need to be implemented as a new object with a deleted attribute,
   replacing the previous version of the object but retaining a pointer
   back to it.

   A separate transaction log needs to be maintained.  Beyond some age,
   the older versions of objects and the the older transaction log
   entries can be removed although it is probably wise to archive them.

B.1.3  committing or disposing of transactions

   The ability to commit large transaction, or reject them as a whole
   poses problems for simplistic database designs.  This form of commit
   operation can be supported quite easily using memory mapped files.
   The changes can be made in virtual memory only and then either
   committed or disposed of.

B.1.4  dealing with concurrency

   Multiple connections may be active.  In addition, a single connection
   may have multiple outstanding operations.  It makes sense to have a
   single process or thread coordinate the responses for a given
   connection and have multiple processes or threads each tending to a
   single operation.  The operations may complete in random order.

   Locking on reads is not essential.  Locking before write access is
   essential.  The simplest approach to locking is to lock at the
   database granularity or at the database and object type granularity.
   Finer locking granularity can also be implemented.  Because there are
   multiple databases, deadlock avoidance must be considered.  The usual
   deadlock avoidance mechanism is to acquire all necessary locks in a
   single operation or acquire locks in a prescribed order.

B.2  Repository Mirroring for Redundancy

   There are numerous reasons why the operator of a repository might
   mirror their own repository.  Possibly the most obvious are
   redundancy and the relative ease of disaster recovery.  Another
   reason might be the widespread use of a small number of
   implementations (but more than one) and the desire to insure that the
   major repository software releases will accept a transaction before
   fully committing to the transaction.

   The operation of a repository mirror used for redundancy is quite
   straightforward.  The transactions of the primary repository host can
   be immediately fed to the redundant repository host.  For tighter
   assurances that false positive confirmations will be sent, as a
   matter of policy the primary repository host can require commit
   confirmation before making a transaction sequence publicly available.

   There are many ways in which the integrity of local data can be
   assured regardless of a local crash in the midst of transaction disk
   writes.  For example, transactions can be implemented as memory

   mapped file operations, with disk synchronization used as the local
   commit mechanism, and disposal of memory copies of pages used to
   handle commit failures.  The old pages can be written to a separate
   file, the new pages written into the database.  The transaction can
   be logged and old pages file can then be removed.  In the event of a
   crash, the existence of a old pages file and the lack of a record of
   the transaction completing would trigger a transaction roll back by
   writing the old pages back to the database file.

   The primary repository host can still sustain severe damage such as a
   disk crash.  If the primary repository host becomes corrupted, the
   use of a mirror repository host provides a backup and can provide a
   rapid recovery from disaster by simply reversing roles.

   If a mirror is set up using a different software implementation with
   commit mirror confirmation required, any transaction which fails due
   a software bug will be deferred indefinitely allowing other
   transactions to proceed rather than halting the remote processing of
   all transactions until the bug is fixed everywhere.

B.3  Trust Relationships

   If all repositories trust each other then there is never a need to
   repeat authorization checks.  This enables a convenient interim step
   for deployment prior to the completion of software supporting that
   capability.  The opposite case is where no repository trusts any
   other repository.  In this case, all repositories must roll forward
   transactions gradually, checking the authorization of each remote
   transaction.

   It is likely that repositories will trust a subset of other
   repositories.  This trust can reduce the amount of processing a
   repository required to maintain mirror images of the full set of
   data.  For example, a subset of repositories might be trustworthy in
   that they take reasonable security measures, the organizations
   themselves have the integrity not to alter data, and these
   repositories trust only a limited set of similar repositories.  If
   any one of these repositories receives a transaction sequence and
   repeats the authorization checks, other major repositories which
   trusts that repository need not repeat the checks.  In addition,
   trust need not be mutual to reap some benefit in reduced processing.

   As a transaction sequence is passed from repository to repository
   each repository signs the transaction sequence before forwarding it.
   If a receiving repository finds that any trusted repository has
   signed the transaction sequence it can be considered authorized since
   the trusted repository either trusted a preceding repository or
   repeated the authorization checks.

B.4  A Router as a Minimal Mirror

   A router could serve as a minimal repository mirror.  The following
   simplifications can be made.

   1. No support for repeating authorization checks or transaction
      authentication checks need be coded in the router.

   2. The router must be adjacent only to trusted mirrors, generally
      operated by the same organization.

   3. The router would only check the authentication of the adjacent
      repository mirrors.

   4. No support for transaction submission or query need be coded in
      the router.  No commit support is needed.

   5. The router can dispose of any object types or attributes not
      needed for configuration of route filters.

   The need to update router configurations could be significantly
   reduced if the router were capable of acting as a limited repository
   mirror.

   A significant amount of non-volatile storage would be needed.  There
   are currently an estimated 100 transactions per day.  If storage were
   flash memory with a limited number of writes, or if there were some
   other reason to avoid writing to flash, the router could only update
   the non-volatile copy every few days.  A transaction sequence request
   can be made to get an update in the event of a crash, returning only
   a few hundred updates after losing a few days of deferred writes.
   The routers can still take a frequent or continuous feed of
   transactions.

   Alternately, router filters can be reconfigured periodically as they
   are today.

B.5  Dealing with Errors

   If verification of an authorization check fails, the entire
   transaction must be rejected and no further advancement of the
   repository can occur until the originating repository corrects the
   problem.  If the problem is due to a software bug, the offending
   transaction can be removed manually once the problem is corrected.
   If a software bug exists in the receiving software, then the

   transaction sequence is stalled until the bug is corrected.  It is
   better for software to error on the side of denying a transaction
   than acceptance, since an error on the side of acceptance will
   require later removal of the effects of the transaction.

C  Deployment Considerations

   This section described deployment considerations.  The intention is
   to raise issues rather than to provide a deployment plan.

   This document calls for a transaction exchange mechanism similar to
   but not identical to the existing "near real time mirroring"
   supported by the code base widely used by the routing registries.  As
   an initial step, the transaction exchange can be implemented without
   the commit protocol or the ability to recheck transaction
   authorization.  This is a fairly minimal step from the existing
   capabilities.

   The transition can be staged as follows:

   1. Modify the format of "near real time mirroring" transaction
      exchange to conform to the specifications of this document.

   2. Implement commit protocol and confirmation support.

   3. Implement remote recheck of authorization.  Prior to this step all
      repositories must be trusted.

   4. Allow further decentralization of the repositories.

D  Privacy of Contact Information

   The routing registries have contained contact information.  The
   redistribution of this contact information has been a delicate issue
   and in some countries has legal implications.

   The person and role objects contain contact information.  These
   objects are referenced by NIC-handles.  There are some attributes
   such as the "changed" and "notify" attributes that require an email
   address.  All of the fields that currently require an email address
   must also accept a NIC-handle.

   The person and role objects should not be redistributed by default.
   If a submission contains an email address in a field such as a
   changed field rather than a NIC-handle the submitter should be aware
   that they are allowing that email address to be redistributed and

   forfeiting any privacy.  Repositories which do not feel that prior
   warnings of this forfeiture are sufficient legal protection should
   reject the submission requesting that a NIC-handle be used.

   Queries to role and person objects arriving at a mirror must be
   referred to the authoritative repository where whatever
   authentication, restrictions, or limitations deemed appropriate by
   that repository can be enforced directly.

   Software should make it possible to restrict the redistribution of
   other entire object types as long as those object types are not
   required for the authorization of additions of other object types.
   It is not possible to redistribute objects with attributes removed or
   altered since this would invalidate the submitter's signature and
   make subsequent authentication checks impossible.  Repositories
   should not redistribute a subset of the objects of a given type.

   Software should also not let a transaction contain both
   redistributable (e.g.  policy objects) and non-redustributable
   objects (e.g.  person) since there is no way to verify the signature
   of these transactions without the non-redustributable objects.

   When redistributing legacy data, contact information in attributes
   such as "changed" and "notify" should be stripped to maintain
   privacy.  The "integrity" attribute on these objects should already
   be set to "legacy" indicating that their origin is questionable, so
   the issue of not being able to recheck signatures is not as
   significant.

References

   [1]  Alaettinoglu, C., Villamizar, C., Gerich, E., Kessens, D.,
        Meyer, D., Bates, T., Karrenberg, D. and M. Terpstra, "Routing
        Policy Specification Language", RFC 2622, June 1999.

   [2]  Bates, T., Gerich, E., Joncheray, L., Jouanigot, J-M.,
        Karrenberg, D., Terpstra, M. and J. Yu, "Representation of IP
        Routing Policies in a Routing Registry (ripe-81++)", RFC 1786,
        March 1995.

   [3]  Villamizar, C., Alaettinoglu, C., Meyer, D. and S. Murphy,
        "Routing Policy System Security", RFC 2725, June 1999.

   [4]  Zsako, J., "PGP Authentication for RIPE Database Updates", RFC
        2726, December 1999.

Security Considerations

   An authentication and authorization model for routing policy object
   submission is provided by [3].  Cryptographic authentication is
   addressed by [4].  This document provides a protocol for the exchange
   of information among distributed routing registries such that the
   authorization model provided by [3] can be adhered to by all
   registries and any deviation (hopefully accidental) from those rules
   on the part of a registry can be identified by other registries or
   mirrors.

Authors' Addresses

   Curtis Villamizar
   Avici Systems
   EMail: curtis@avici.com

   Cengiz Alaettinoglu
   ISI
   EMail: cengiz@ISI.EDU

   Ramesh Govindan
   ISI
   EMail: govindan@ISI.EDU

   David M. Meyer
   Cisco
   EMail: dmm@cisco.com

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Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.

 

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