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Versions: 00 01 02                                                      
Network Working Group                                            E. Chen
Internet Draft                                                  K. Patel
Intended Status: Standards Track                                   A. Lo
Expiration Date: December 11, 2011                         Cisco Systems
                                                           June 10, 2011


        Extended Community Based Outbound Route Filter for BGP-4
                draft-chen-bgp-ext-community-orf-01.txt


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
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Chen, Patel & Lo                                                [Page 1]


Internet Draft  draft-chen-bgp-ext-community-orf-01.txt    June 10, 2011


   described in the Simplified BSD License.


Abstract

   This document defines two new Outbound Router Filter types for BGP,
   termed "Extended Community Outbound Route Filter Type I", and
   "Extended Community Outbound Route Filter Type II", that can be used
   to perform extended community based route filtering.


1. Introduction

   The Outbound Route Filtering Capability defined in [RFC5291] provides
   a mechanism for a BGP speaker to send to its BGP peer a set of
   Outbound Route Filters (ORFs) that can be used by its peer to filter
   its outbound routing updates to the speaker.

   This document defines two new Outbound Router Filter type for BGP
   [RFC4271], termed "Extended Community Outbound Route Filter Type I",
   and "Extended Community Outbound Route Filter Type II", that can be
   used to perform the extended community [RFC4360, RFC5760] based route
   filtering.  The former can be used only for the 8-octet extended
   communities defined in [RFC4360], and is retained for backward
   compatibility.   The latter can be used for the extended communities
   defined in both [RFC4360] and [RFC5701].  This document also
   specifies procedures for performing route filtering when both types
   are supported.


1.1. Specification of Requirements

   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 RFC2119 [RFC2119].
















Chen, Patel & Lo                                                [Page 2]


Internet Draft  draft-chen-bgp-ext-community-orf-01.txt    June 10, 2011


2. Extended Communities ORF Type I

   The Extended Community ORF Type I allows to express ORFs in terms of
   the 8-octet BGP Extended Communities defined in [RFC4360].  That is,
   the Extended Communities ORF Type I provides the 8-octet Extended
   Community based route filtering.

   Conceptually the ORF entry of the Extended Communities ORF Type I
   consists of a single Extended Community of 8 octets.

   The sender SHOULD set the value of the Match field to PERMIT; the
   receiver SHOULD ignore the value of the Match field.

   The remote peer should consider only those routes whose Extended
   Communities attribute has at least one Extended Community in common
   with the Extended Communities list specified in the ORF.


2.1. Encoding

   The value of the ORF-Type for the Extended Communities ORF Type I is
   3.

   The type-specific part of the Extended Communities ORF Type I
   consists of a single Extended Community as specified in [RFC4360].


3. Extended Communities ORF Type II

   The Extended Community ORF Type II allows to express ORFs in terms of
   the BGP Extended Communities defined in both [RFC4360] and [RFC5701].
   That is, the Extended Communities ORF Type II provides Extended
   Community based route filtering.

   Conceptually the ORF entry of the Extended Communities ORF-Type
   consists of a single Extended Community, of either 8 octets, or 20
   octets.

   The sender SHOULD set the value of the Match field to PERMIT; the
   receiver SHOULD ignore the value of the Match field.

   The remote peer should consider only those routes whose Extended
   Communities attribute has at least one Extended Community in common
   with the Extended Communities list specified in the ORF.







Chen, Patel & Lo                                                [Page 3]


Internet Draft  draft-chen-bgp-ext-community-orf-01.txt    June 10, 2011


3.1. Encoding

   The value of the ORF-Type for the Extended Communities ORF Type II is
   <TBD>.

   The type-specific part of the Extended Communities ORF Type II
   consists of a single Extended Community encoded as the following


               +------------------------------------------+
               |   Ext-community Length (1 octet)         |
               +------------------------------------------+
               |   Ext-community value (8 or 20 octets)   |
               +------------------------------------------+


   where the "Ext-community Length" field contains the number of octets
   of the extended community in the "Ext-community value" field.


4. Operations

   In addition to the general procedures defined in [RFC5291], the
   following procedures are specified for the Extended Community ORF
   types.

   As the Extended Community ORF Type I can only handled the extended
   communities defined in [RFC4360], clearly it SHOULD NOT be enabled
   over a BGP session that exchanges routes with the extended
   communities defined in [RFC5701].

   The Extended Community ORF Type I is retained for backward
   compatibility.  An implementation SHOULD migrate to the Extended
   Community ORF Type II in order to handle the extended communities
   defined in both [RFC4360] and [RFC5701].

   During the lifetime of a BGP session, ORF entries of only one of the
   two types would be carried in the ROUTE-REFRESH message, and be used
   in route filtering.  When both types are allowed, respectively, by
   the "Send/Receive" fields in the Outbound Route Filtering Capability
   and the procedures specified in [RFC5291], Type II would be used.
   When only one of the two types is allowed by the "Send/Receive"
   fields in the Outbound Route Filtering Capability and the procedures
   specified in [RFC5291], that particular type would be used.







Chen, Patel & Lo                                                [Page 4]


Internet Draft  draft-chen-bgp-ext-community-orf-01.txt    June 10, 2011


5. IANA Considerations

   This document specifies two new Outbound Route Filtering (ORF) types,
   Extended Community ORF Type I (with ORF-type value 3), and the
   Extended Community ORF Type II (with ORF-type value <TBD>).


6. Security Considerations

   This extension to BGP does not change the underlying security issues
   in BGP [RFC4271].


7. Acknowledgements

   We would like to thank Yakov Rekhter for his contribution on this
   work.


8. Normative References

   [RFC4271]   Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
               Border Gateway Protocol 4 (BGP-4)", RFC 4271, January
               2006.

   [RFC4360]   Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
               Communities Attribute", RFC 4360, February 2006.

   [RFC5701]   Rekhter, Y., "IPv6 Address Specific BGP Extended
               Community Attribute", RFC 5701, November2009.

   [RFC5291]   Chen, E., and Rekhter, Y., "Outbound Route Filtering
               Capability for BGP-4", RFC 5291, August 2008.

   [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
               Requirement Levels", BCP 14, RFC 2119, March 1997.















Chen, Patel & Lo                                                [Page 5]


Internet Draft  draft-chen-bgp-ext-community-orf-01.txt    June 10, 2011


9. Author Information

   Enke Chen
   Cisco Systems, Inc.
   170 W. Tasman Dr.
   San Jose, CA 95134
   USA

   EMail: enkechen@cisco.com


   Keyur Patel
   Cisco Systems
   170 W. Tasman Drive
   San Jose, CA  95134
   USA

   Email: keyupate@cisco.com


   Alton Lo
   Cisco Systems
   170 W. Tasman Drive
   San Jose, CA  95134
   USA

   Email: altonlo@cisco.com
























Chen, Patel & Lo                                                [Page 6]