Network Working Group Yakov Rekhter (Juniper Networks) Internet Draft Srihari R. Sangli (Cisco Systems) Expiration Date: September 2009 Daniel Tappan Intended Status: Proposed Standard Four-octet AS Specific BGP Extended Community draft-ietf-l3vpn-as4octet-ext-community-03.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. 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Without obtaining an adequate license from the person(s) controlling Sangli, Tappan, Rekhter [Page 1] Internet Draftdraft-ietf-l3vpn-as4octet-ext-community-03.txt March 2009 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. Abstract This document defines a new type of a BGP extended community - four- octet AS specific extended community. This community allows to carry 4 octet autonomous system numbers. 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 RFC 2119 [RFC2119]. 1. Introduction This document defines a new type of BGP extended community ([RFC4360]) - four-octet AS specific extended community. This type of extended community is similar to the two-octet AS specific extended community, except that it can carry a four octets autonomous system number. 2. Four-octet AS specific extended community This is an extended type with Type Field comprising of 2 octets and Value Field comprising of 6 octets. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0x02 or 0x42 | Sub-Type | Global Administrator : +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ : Global Administrator (cont.) | Local Administrator | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The value of the high-order octet of this extended type is either 0x02 (for transitive communities) or 0x42 (for non-transitive commu- nities). The low-order octet of this extended type is used to Sangli, Tappan, Rekhter [Page 2] Internet Draftdraft-ietf-l3vpn-as4octet-ext-community-03.txt March 2009 indicate sub-types. The Value Field consists of two sub-fields: Global Administrator sub-field: 4 octets This sub-field contains a 4-octets Autonomous System number assigned by IANA. Local Administrator sub-field: 2 octets The organization identified by 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 commu- nity. 3. Considerations for two-octet Autonomous Systems As per [RFC4893], a two-octet Autonomous System number can be con- verted into a 4-octet Autonomous System number by setting the two high-order octets of the 4-octet field to zero. As a consequence, at least in principle an autonomous system that uses a two-octet Autonomous System number could use either two-octet or four-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 two-octet and four-octet specific extended communities, autonomous systems that use two-octet Autonomous System numbers SHOULD use two-octet AS specific extended communities rather than four-octet AS specific extended communities. Sangli, Tappan, Rekhter [Page 3] Internet Draftdraft-ietf-l3vpn-as4octet-ext-community-03.txt March 2009 4. IANA Considerations This document defines a class of extended communities called four- octet AS specific extended community for which the IANA is to create and maintain a registry entitled Four-octet AS Specific Extended Com- munity. All the communities in this class are of extended Types. Future assignment are to be made using the "First Come First Served" policy defined in [RFC5226]. The Type values for the transitive com- munities of the four-octet AS specific extended community class are 0x0200-0x02ff, and for the non-transitive communities of that class are 0x4200-0x42ff. Assignments consist of a name and the value. This document makes the following assignments for the four-octet AS specific extended community: Name Type Value ---- ---------- four-octet AS specific Route Target 0x0202 four-octet AS specific Route Origin 0x0203 5. Security Considerations All the security considerations for BGP Extended Communities apply here. 6. Acknowledgements Thanks to Bruno Decraene for his contributions to this document. 7. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5226] Narten, T., Alvestrand, H., "Guidelines for Writing an IANA Considerations Section in RFCs", RFC5226, May 2008. [RFC4360] Srihari R. Sangli, Daniel Tappan, Yakov Rekhter, "BGP Extended Communities Attribute", RFC 4360, February 2006. [RFC4893] Vohra, Q., Chen, E., "BGP Support for Four-octet AS Number Space", RFC 4893, May 2007. Sangli, Tappan, Rekhter [Page 4] Internet Draftdraft-ietf-l3vpn-as4octet-ext-community-03.txt March 2009 8. Non-normative References 9. Author Information Yakov Rekhter Juniper Networks, Inc. e-mail: yakov@juniper.net Srihari R. Sangli Cisco Systems, Inc. e-mail: rsrihari@cisco.com Dan Tappan Boxborough MA e-mail: Dan.Tappan@Gmail.com Sangli, Tappan, Rekhter [Page 5]