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
  (http://trustee.ietf.org/license-info) in effect on the date of
  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: [email protected]








































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