    Network Working Group                                         Y. Rekhter
    Request for Comments: 5701                              Juniper Networks
    Category: Standards Track                                  November 2009

             IPv6 Address Specific BGP Extended Community Attribute

    Abstract

       Current specifications of BGP Extended Communities (RFC 4360) support
       the IPv4 Address Specific Extended Community, but do not support an
       IPv6 Address Specific Extended Community.  The lack of an IPv6
       Address Specific Extended Community may be a problem when an
       application uses the IPv4 Address Specific Extended Community, and
       one wants to use this application in a pure IPv6 environment.  This
       document defines a new BGP attribute, the IPv6 Address Specific
       Extended Community, that addresses this problem.  The IPv6 Address
       Specific Extended Community is similar to the IPv4 Address Specific
       Extended Community, except that it carries an IPv6 address rather
       than an IPv4 address.

    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) 2009 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
       Provisions Relating to IETF Documents
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       publication of this document.  Please review these documents
       carefully, as they describe your rights and restrictions with respect
       to this document.  Code Components extracted from this document must
       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 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

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    RFC 5701       IPv6 Specific Extended Community Attribute  November 2009

       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
       outside the IETF Standards Process, and derivative works of it may
       not be created outside the IETF Standards Process, except to format
       it for publication as an RFC or to translate it into languages other
       than English.

    1.  Introduction

       Current specifications of BGP Extended Communities [RFC4360] support
       the IPv4 Address Specific Extended Community, but do not support an
       IPv6 Address Specific Extended Community.  The lack of an IPv6
       Address Specific Extended Community may be a problem when an
       application uses IPv4 Address Specific Extended Community and one
       wants to use this application in a pure IPv6 environment.

       Because the BGP Extended Community attribute defines each BGP
       Extended Community as being 8 octets long, it is not possible to
       define the IPv6 Specific Extended Community using the existing BGP
       Extended Community attribute [RFC4360].  Therefore, this document
       defines a new BGP attribute, the IPv6 Address Specific Extended
       Community, that has a structure similar to the IPv4 Address Specific
       Extended Community, and thus could be used in a pure IPv6 environment
       as a replacement of the IPv4 Address Specific Extended Community.

    2.  IPv6 Address Specific BGP Extended Community Attribute

       The IPv6 Address Specific Extended Community Attribute is a
       transitive, optional BGP attribute [BGP-4].  The attribute consists
       of a set of "IPv6 Address Specific extended communities".  All routes
       with the IPv6 Address Specific Extended Community attribute belong to
       the communities listed in the attribute.

       Just like all other BGP Extended Communities, the IPv6 Address
       Specific Extended Community supports multiple sub-types.

       Each IPv6 Address Specific extended community is encoded as a
       20-octet quantity, as follows:

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    RFC 5701       IPv6 Specific Extended Community Attribute  November 2009

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | 0x00 or 0x40  |    Sub-Type   |    Global Administrator       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |          Global Administrator (cont.)                         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |          Global Administrator (cont.)                         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |          Global Administrator (cont.)                         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Global Administrator (cont.)  |    Local Administrator        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       The first high-order octet indicates whether a particular sub-type of
       this community is transitive across Autonomous Systems (ASes) (0x00),
       or not (0x40).  The second high-order octet of this extended type is
       used to indicate sub-types.  The sub-types are the same as for the
       IPv4 Address Specific Extended Community.

       Global Administrator field: 16 octets

          This field contains an IPv6 unicast address assigned by one of the
          Internet registries.

       Local Administrator field: 2 octets

          The organization that has been assigned the IPv6 address in the
          Global Administrator field can encode any information in this
          field.  The format and meaning of the value encoded in this field
          should be defined by the sub-type of the community.

    3.  IANA Considerations

       This document defines a new BGP attribute, called the IPv6 Address
       Specific Extended Community (value 25).

       This document defines a class of extended communities, called the
       IPv6 Address Specific Extended Community, for which the IANA has
       created and will maintain a registry entitled "IPv6 Address Specific
       Extended Community".  Future assignments are to be made using the
       "First Come First Served" policy defined in [RFC5226].  The Type
       values for the transitive communities of the IPv6 Address Specific
       Extended Community class are 0x0000-0x00ff; for the non-transitive
       communities of that class, they are 0x4000-0x40ff.  Assignments
       consist of a name and the value.

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    RFC 5701       IPv6 Specific Extended Community Attribute  November 2009

       This document makes the following assignments for the IPv6 Address
       Specific extended community types:

          Name                                     Type Value
          ----                                     --------------
          IPv6 address specific Route Target       0x0002
          IPv6 address specific Route Origin       0x0003

    4.  Security Considerations

       This document does not add new security issues.  All the security
       considerations for BGP Extended Communities apply here.  At the time
       that this document was written, there were significant efforts
       underway to improve the security properties of BGP.  For examples of
       documents that have been produced up to this time of publication, see
       [RFC4593] and [SIDR].

       There is a potential serious issue if a malformed, optional,
       transitive attribute is received.  This issue and the steps to avoid
       it are discussed in [OPT_TRANS].

    5.  Acknowledgements

       Many thanks to Michael Lundberg and Emre Ertekin for their review and
       comments.

    6.  References

    6.1.  Normative References

       [BGP-4]      Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
                    Border Gateway Protocol 4 (BGP-4)", RFC 4271, January
                    2006.

       [RFC5226]    Narten, T. and H. Alvestrand, "Guidelines for Writing an
                    IANA Considerations Section in RFCs", BCP 26, RFC 5226,
                    May 2008.

       [RFC4360]    Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
                    Communities Attribute", RFC 4360, February 2006.

    6.2.  Informative References

       [OPT_TRANS]  Scudder, J. and E. Chen, "Error Handling for Optional
                    Transitive BGP Attributes", Work in Progress, April
                    2009.

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    RFC 5701       IPv6 Specific Extended Community Attribute  November 2009

       [RFC4593]    Barbir, A., Murphy, S., and Y. Yang, "Generic Threats to
                    Routing Protocols", RFC 4593, October 2006.

       [SIDR]       Lepinski, M. and S. Kent, "An Infrastructure to Support
                    Secure Internet Routing", Work in Progress, July 2009.

    Author's Address

       Yakov Rekhter
       Juniper Networks, Inc.
       EMail: yakov@juniper.net

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