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
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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
Rekhter 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:
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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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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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[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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