Network Working Group B. Decraene
Internet-Draft France Telecom - Orange
Intended status: Standards Track P. Francois
Expires: April 20, 2011 UCL
October 17, 2010
Reserved BGP extended communities
draft-decraene-idr-reserved-extended-communities-00
Abstract
This document assigns two BGP extended community types, one
transitive and one non-transitive. It also defines two IANA
registries in order to allow the allocation of reserved transitive
and non-transitive extended communities. These are similar to the
existing reserved (formerly Well-known) BGP communities defined in
RFC 1997 but provides an easier control of inter-AS community
advertissement as a community could be chosen as transitive or non-
transitive across ASes.
Requirements Language
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 [RFC2119].
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on April 20, 2011.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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described in the Simplified BSD License.
1. Introduction
RFC1997 [RFC1997] defines the BGP community attribute and some BGP
Well known communities whose meaning SHALL be understood by all
implementations compliant with RFC1997 [RFC1997]). New reserved
communities can be registred in the IANA "BGP Well-known Communities"
registry but can't anymore be considered as well known.
Implementations which do not reconize those new reserved communities
will propagate them from BGP neigbour to BGP neigbour and from AS to
AS with an unlimited scope.
RFC 4360[RFC4360] defines the BGP extended community attribute with a
structure including a type and a transitive bit "T". The transitive
bit, when set, allows to restrict the scope of the community within
an AS. Without structure, this can only be accomplished by
explicitly enumerating all community values that will be denied or
allowed and passed to BGP speakers in neighboring ASes. RFC
4360[RFC4360] defines IANA registries to allocate BGP Extended
Communities types. Each type is able to encode 2^48 or 2^56 values
depending on the type being extended or regular. It does not define
an IANA registry to allocate single reserved communities. Therefore,
one needing to reserve a single non-transitive extended community
would need to reserve an extended subtype which represents 2^48
communities. This would both waste the ressources and disable the
ability to define global policies on reserved communities, such as to
filter them out.
This document assigns two BGP extended community types, one
transitive and one non-transitive. It also defines two IANA
registries in order to allow the allocation of reserved transitive
and non-transitive extended communities. These are similar to the
existing reserved ("Well-known") BGP communities defined in RFC 1997
but provides an easier control of inter-AS community advertissement
as a community could be chosen as transitive or non-transitive across
ASes.
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2. IANA Considerations
IANA is requested to assign, from the registry "BGP Extended
Communities Type - extended, transitive type", a type value TBD for
"BGP Reserved transitive extended communities":
Registry Name: BGP Extended Communities Type - extended, transitive
Name Type Value
---- ----------
BGP Reserved transitive extended communities TBD (e.g. 0x9000)
IANA is requested to assign, from the registry "BGP Extended
Communities Type - extended, non-transitive", a type value TBD for
"BGP Reserved non-transitive extended communities":
Registry Name: BGP Extended Communities Type - extended, non-transitive
Name Type Value
---- ----------
BGP Reserved non-transitive extended communities TBD (e.g. 0xd000)
Note to the IANA: suggested value for the two reserved BGP Extended
Communities extended type are 0x9000 and 0xd000. Otherwise, both
values should be identical, except for their T - Transitive bit (bit
1 as defined in RFC 4360 [RFC4360]).
The IANA is requested to create and maintain a registry entitled "BGP
Reserved transitive extended communities".
Registry Name: BGP Reserved transitive extended communities
Range Registration Procedures
--------------------------- -------------------------
0x000000000000-FFFFFFFEFFFF Reserved
0xFFFFFFFF0000-00FFFFFF8000 First Come First Served
0x00FFFFFF8001-FFFFFFFFFFFF Standards Action/Early IANA Allocation
The IANA is requested to create and maintain a registry entitled "BGP
Reserved non-transitive extended communities".
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Registry Name: BGP Reserved non-transitive extended communities
Range Registration Procedures
--------------------------- -------------------------
0x000000000000-FFFFFFFEFFFF Reserved
0xFFFFFFFF0000-00FFFFFF8000 First Come First Served
0x00FFFFFF8001-FFFFFFFFFFFF Standards Action/Early IANA Allocation
An application may need both a transitive and non-transitive reserved
community. It may be beneficial to have the same value for both
communities. (Note that both extended community will still be
different as they will differ from their T bit). IThe IANA SHOULD
try to accomodate such request to have both a transitive and non-
transitive reserved community with the same value for both.
3. Security Considerations
This document defines IANA actions. In itself, it has no impact on
the security of the BGP protocol.
4. Normative References
[RFC1997] Chandrasekeran, R., Traina, P., and T. Li, "BGP
Communities Attribute", RFC 1997, August 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, February 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
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Authors' Addresses
Bruno Decraene
France Telecom - Orange
38-40 rue du General Leclerc
Issy Moulineaux cedex 9 92794
France
Email: bruno.decraene@orange-ftgroup.com
Pierre Francois
UCL
Place Ste Barbe, 2
Louvain-la-Neuve 1348
BE
Email: francois@info.ucl.ac.be
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