Network Working Group B. Decraene
Internet-Draft France Telecom - Orange
Intended status: Standards Track P. Francois
Expires: August 11, 2011 UCL
February 07, 2011
Reserved BGP extended communities
draft-ietf-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
advertisement 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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 11, 2011.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
Decraene & Francois Expires August 11, 2011 [Page 1]
Internet-Draft Reserved extended communities February 2011
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 Simplified BSD License.
1. Introduction
[RFC1997] defines the BGP community attribute and some BGP Well known
communities whose meaning SHALL be understood by all compliant
implementations. New reserved communities can be registered in the
IANA "BGP Well-known Communities" registry but it can't be assumed
anymore that they will be known by all BGP implementations.
Implementations or BGP policies which recognize them will behave as
specified. Implementation which do not recognize those new reserved
communities will propagate them from BGP neighbor to BGP neighbor and
from AS to AS with an unlimited scope.
There is currently no agreed way to reserve a non transitive well
known community:
o [RFC1997] defines BGP Well-known communities with no structure to
set their transitiveness across ASes. Without structure, non
transitive communities can only be filtered by explicitly
enumerating all community values that will be denied or allowed to
BGP speakers in neighboring ASes. This is not satisfactory as
this would require upgrading all border routers to understand this
community before its first usage.
o [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. But their is no IANA registry to allocate
a (single) well known extended community. 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. Therefore, one needing to
reserve a single non-transitive extended community would need to
reserve an extended subtype which represents 2^48 communities,
while a single value is used. This would both waste the resources
and disable the ability to define global policies on reserved
communities, such as to filter them out.
Decraene & Francois Expires August 11, 2011 [Page 2]
Internet-Draft Reserved extended communities February 2011
To address this limitation, 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 Well-known BGP communities defined in RFC
1997 but provides a control on inter-AS community advertisement as a
community could be chosen as transitive or non-transitive across
ASes.
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 [RFC4360]).
The IANA is requested to create and maintain a registry entitled "BGP
Reserved transitive extended communities":
Decraene & Francois Expires August 11, 2011 [Page 3]
Internet-Draft Reserved extended communities February 2011
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":
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). The IANA SHOULD try
to accommodate 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.
Decraene & Francois Expires August 11, 2011 [Page 4]
Internet-Draft Reserved extended communities February 2011
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
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
Decraene & Francois Expires August 11, 2011 [Page 5]
