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Network Working Group                                         Y. RekhterRequest for Comments: 5701                              Juniper NetworksCategory: Standards Track                                  November 2009IPv6 Address Specific BGP Extended Community AttributeAbstract   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 toBCP 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 allowRekhter                     Standards Track                     [Page 1]

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:Rekhter                     Standards Track                     [Page 2]

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.Rekhter                     Standards Track                     [Page 3]

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       0x00034.  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.  References6.1.  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.Rekhter                     Standards Track                     [Page 4]

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.netRekhter                     Standards Track                     [Page 5]