Network Working Group E. Chen Request for Comments: 4486 Cisco Systems Category: Standards Track V. Gillet France Telecom April 2006 Subcodes for BGP Cea Notification Message
Status of This Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for
improvements. Plea 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) The Internet Society (2006).
Abstract
This document defines veral subcodes for the BGP Cea NOTIFICATION message that would provide more information to aid network operators in correlating network events and diagnosing BGP peering issues.
1. Introduction
This document defines veral subcodes for the BGP Cea NOTIFICATION message that would provide more information to aid network operators in correlating network events and diagnosing BGP peering issues. It also recommends that a BGP speaker implement a backoff mechanism in
re-trying a BGP connection after the speaker receives a NOTIFICATION message with certain CEASE subcode.
2. 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]. Chen & Gillet Standards Track [Page 1]
3. Subcode Definition
The following subcodes are defined for the Cea NOTIFICATION
message:
Subcode Symbolic Name
1 Maximum Number of Prefixes Reached
2 Administrative Shutdown
3 Peer De-configured
4 Administrative Ret
5 Connection Rejected
6 Other Configuration Change
7 Connection Collision Resolution
8 Out of Resources
4. Subcode Usage
If a BGP speaker decides to terminate its peering with a neighbor
becau the number of address prefixes received from the neighbor
exceeds a locally configured upper bound (as described in [BGP-4]),
then the speaker MUST nd to the neighbor a NOTIFICATION message
with the Error Code Cea 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, as shown in Figure 1, where the meaning and u of the <AFI, SAFI>
tuple is the same as defined in [BGP-MP], Section 7.
+-------------------------------+
| AFI (2 octets) |
+-------------------------------+
| SAFI (1 octet) |
+-------------------------------+
| Prefix upper bound (4 octets) |
+-------------------------------+
Figure 1: Optional Data Field
If a BGP speaker decides to administratively shut down its peering
with a neighbor, then the speaker SHOULD nd a NOTIFICATION message with the Error Code Cea and the Error Subcode "Administrative
Shutdown".
If a BGP speaker decides to de-configure a peer, then the speaker
SHOULD nd a NOTIFICATION message with the Error Code Cea and the Error Subcode "Peer De-configured".
Chen & Gillet Standards Track [Page 2]
If a BGP speaker decides to administratively ret the peering with a neighbor, then the speaker SHOULD nd a NOTIFICATION message with
the Error Code Cea and the Error Subcode "Administrative Ret".
If a BGP speaker decides to disallow a BGP connection (e.g., the peer is not configured locally) after the speaker accepts a transport
protocol connection, then the BGP speaker SHOULD nd a NOTIFICATION message with the Error Code Cea and the Error Subcode "Connection
Rejected".
If a BGP speaker decides to administratively ret the peering with a neighbor due to a configuration change other than the ones described above, then the speaker SHOULD nd a NOTIFICATION message with the
Error Code Cea and the Error Subcode "Other Configuration Change". If a BGP speaker decides to nd a NOTIFICATION message with the
Error Code Cea as a result of the collision resolution procedure
(as described in [BGP-4]), then the subcode SHOULD be t to
"Connection Collision Resolution".
If a BGP speaker runs out of resources (e.g., memory) and decides to ret a ssion, then the speaker MAY nd a NOTIFICATION message
with the Error Code Cea and the Error Subcode "Out of Resources".
It is RECOMMENDED that a BGP speaker behave as though the
DampPeerOscillations attribute [BGP-4] were true for this peer when
re-trying a BGP connection after the speaker receives a Cea
NOTIFICATION message with a subcode of "Administrative Shutdown",
"Peer De-configured", "Connection Rejected", or "Out of Resources".
An implementation SHOULD impo an upper bound on the number of
concutive automatic retries. Once this bound is reached, the
implementation would stop re-trying any BGP connections until some
administrative intervention, i.e., t the AllowAutomaticStart
attribute [BGP-4] to FALSE.
5. IANA Considerations
This document defines the subcodes 1 - 8 for the BGP Cea
NOTIFICATION message. Future assignments are to be made using either the Standards Action process defined in [RFC-2434], or the Early IANA Allocation process defined in [RFC-4020]. Assignments consist of a
name and the value.
6. Security Considerations
This extension to BGP does not change the underlying curity issues inherent in the existing BGP.
Chen & Gillet Standards Track [Page 3]
7. Acknowledgements
The authors would like to thank Yakov Rekhter, Pedro Marques, Andrew Lange, and Don Goodspeed for their review and suggestions.
8. References
8.1. Normative References
[BGP-4] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[BGP-MP] Bates, T., Rekhter, Y., Chandra, R., and D. Katz,
"Multiprotocol Extensions for BGP-4", RFC 2858, June 2000. [RFC-2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[RFC-2119] Bradner, S., "Key words for u in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[RFC-4020] Kompella, K. and A. Zinin, "Early IANA Allocation of
Standards Track Code Points", BCP 100, RFC 4020, February 2005.
Chen & Gillet Standards Track [Page 4]
Authors’ Address
Enke Chen
Cisco Systems, Inc.
170 W. Tasman Dr.
San Jo, CA 95134
USA
EMail:
Vincent Gillet
France Telecom Longues Distances
61, rue des Archives
75003 Paris FRANCE
EMail:
Chen & Gillet Standards Track [Page 5]
Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licens and restrictions
contained in BCP 78, and except as t forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual
Property
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 u of the technology described in
this document or the extent to which any licen under such rights
might or might not be available; nor does it reprent that it has
made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licens to be made available, or the result of an
attempt made to obtain a general licen or permission for the u of such proprietary rights by im
plementers or urs of this
specification can be obtained from the IETF on-line IPR repository at /ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Plea address the information to the IETF at
Acknowledgement
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
Chen & Gillet Standards Track [Page 6]
