Network Working Group Y. Rekhter Request for Comments: 5668 Juniper Networks Category: Standards Track S. Sangli Cisco Systems D. Tappan Consultant October 2009 4-Octet AS Specific BGP Extended Community
AbstractThis document defines a new type of a BGP extended community, which carries a 4-octet Autonomous System (AS) number. 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 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 allow 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. RFC4360]: a 4-octet AS specific extended community. This type of extended community is similar to the 2-octet AS specific extended community, except that it can carry a 4-octet Autonomous System number. RFC2119].
Local Administrator sub-field: 2 octets The organization identified by the Autonomous System number in the Global Administrator sub-field can encode any information in this sub-field. The format and meaning of the value encoded in this sub-field should be defined by the sub-type of the community. RFC4893], a 2-octet Autonomous System number can be converted into a 4-octet Autonomous System number by setting the 2 high-order octets of the 4-octet field to zero. As a consequence, at least in principle, an Autonomous System that uses a 2-octet Autonomous System number could use either 2-octet or 4-octet AS specific extended communities. This is undesirable, as both communities would be treated as different, even if they had the same Sub-Type and Local Administrator values. Therefore, for backward compatibility with existing deployments and to avoid inconsistencies between 2-octet and 4-octet specific extended communities, Autonomous Systems that use 2-octet Autonomous System numbers SHOULD use 2-octet AS specific extended communities rather than 4-octet AS specific extended communities. RFC5226]. The Type values for the transitive communities of the 4-octet AS specific extended community class are 0x0200-0x02ff; for the non-transitive communities of that class, they are 0x4200-0x42ff. Assignments consist of a name and the value. This document makes the following assignments for the 4-octet AS specific extended community: Name Type Value ---- ---------- four-octet AS specific Route Target 0x0202 four-octet AS specific Route Origin 0x0203
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]. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [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. [RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS Number Space", RFC 4893, May 2007. [OPT_TRANS] Scudder, J., and E. Chen, "Error Handling for Optional Transitive BGP Attributes", Work in Progress, April 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.