Network Working Group Enke Chen Internet Draft
Redback NetworksCisco Systems Expiration Date: October 2004December 2005 Vincent Gillet France Telecom Subcodes for BGP Cease Notification Message draft-ietf-idr-cease-subcode-05.txtdraft-ietf-idr-cease-subcode-06.txt 1. Status of this Memo This documentBy submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is an Internet-Draftaware have been or will be disclosed, and isany of which he or she becomes aware will be disclosed, in full conformanceaccordance with all provisions ofSection 106 of RFC2026.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"work in progress.''progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 2. Abstract This document defines several subcodes for the BGP Cease NOTIFICATION message that would provide more information to aid network operators in co-relatingcorrelating network events and diagnosing BGP peering issues. 3. 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 [RFC-2119]. 4. Introduction This document defines several subcodes for the BGP Cease NOTIFICATION message that would provide more information to aid network operators in co-relatingcorrelating network events and diagnosing BGP peering issues. 5. Subcode Definition The following subcodes are defined for the Cease NOTIFICATION message: Subcode Symbolic Name 1 Maximum Number of Prefixes Reached 2 Administrative Shutdown 3 Peer UnconfiguredDe-configured 4 Administrative Reset 5 Connection Rejected 6 Other Configuration Change 7 Connection Collision Resolution 8 Out of ResourceResources 6. Subcode Usage If a BGP speaker decides to terminate its peering with a neighbor because the number of address prefixes received from the neighbor exceeds a locally configured upper bound (as described in [BGP-4]), then the speaker MUST send to the neighbor a NOTIFICATION message with the Error Code Cease, and the Error Subcode "Maximum Number of Prefixes Reached". The message MAY optionally include the Address Family information [BGP-MP] and the upper bound in the "Data" field withas shown in Figure 1 where the following format:meaning and use of the <AFI, SAFI> tuple is the same as defined in [BGP-MP, sect. 7]. +-------------------------------+ | AFI (2 octets) | +-------------------------------+ | SAFI (1 octet) | +-------------------------------+ | Prefix upper bound (4 octets) | +-------------------------------+ where the meaning and use of the <AFI, SAFI> tuple is the same as defined in [BGP-MP, sect. 7].Figure 1 Optional Data Field If a BGP speaker decides to administratively shut down its peering with a neighbor, then the speaker SHOULD send a NOTIFICATION message with the Error Code Cease, and the Error Subcode "Administrative Shutdown". If a BGP speaker decides to unconfigurede-configure a peer, then the speaker SHOULD send a NOTIFICATION message with the Error Code Cease, and the Error Subcode "Peer Unconfigured".De-configured". If a BGP speaker decides to administratively reset the peering with a neighbor, then the speaker SHOULD send a NOTIFICATION message with the Error Code Cease, and the Error Subcode "Administrative Reset". If a BGP speaker decides to dis-allow a BGP connection (e.g., the peer is not configured locally) after the speaker accepts a transport protocol connection, then the BGP speaker SHOULD send a NOTIFICATION message with the Error Code Cease, and the Error Subcode "Connection Rejected". If a BGP speaker decides to administratively reset the peering with a neighbor due to a configuration change other than the ones described above, then the speaker SHOULD send a NOTIFICATION message with the Error Code Cease, and the Error Subcode "Other Configuration Change". If a BGP speaker decides to send a NOTIFICATION message with the Error Code Cease as a result of the collision resolution procedure (as described in [BGP-4]), then the subcode SHOULD be set to "Connection Collision Resolution". If a BGP speaker runs out of resourceresources (e.g., memory) and decides to reset a session, then the speaker MAY send a NOTIFICATION message with the Error Code Cease, and the Error Subcode "Out of Resource".Resources". It is RECOMMENDED that a BGP speaker implement a backoff mechanism in re-trying a BGP connection after the speaker receives a Cease NOTIFICATION message with subcode of "Administrative Shutdown", or "Peer Unconfigured",De-configured", or "Connection Rejected", or "Out of Resource".Resources". An implementation MAYSHOULD impose an upper bound on the number of consecutive automatic retries. Once this bound is reached, the implementation would stop re-trying any BGP connections until some administrative intervention. 7. IANA Considerations This document defines severalthe subcodes 1 - 8 for the BGP Cease NOTIFICATION messsage. New subcodes MUST onlymessage. Future assignments are to be introducedmade using either the Standards Action process defined in [RFC-2434], or the Early IANA Allocation process defined in [kompella-zinin], or the "First Come First Served" policy defined in [RFC-2434]. 8. Security Considerations This extension to BGP does not change the underlying security issues inherent in the existing BGP. 9. Acknowledgments The authors would like to thank Yakov Rekhter, Pedro Marques, Andrew Lange and Don Goodspeed for their review and suggestions. 10. Normative References [BGP-4] Y. Rekhter, T. Li and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", <draft-ietf-idr-bgp4-23.txt>, November 2003.<draft-ietf-idr-bgp4-26.txt>, October 2004. [BGP-MP] Bates, T., Chandra, R., Katz, D. and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 2858, June 2000. [RFC-2434] Narten, T., Alvestrand, H., "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 2434, October 1998. [RFC-2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 11. Non-normative References [kompella-zinin] Kompella, K., Zinin, A., "Early IANA Allocation of Standards Track Codepoints", Work in progress 12. Author Information Enke Chen Redback Networks,Cisco Systems, Inc. 300 Holger Way170 W. Tasman Dr. San Jose, CA 95134 Email: email@example.com@cisco.com Vincent Gillet France Telecom Longues Distances 24661, rue de Bercy 75594des Archives 75003 Paris Cedex 12FRANCE Email: firstname.lastname@example.org 13. Intellectual Property Considerations The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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