Network Working Group E. Chen
Request for Comments: 4486 Cisco Systems
Category: Standards Track V. Gillet
France Telecom
April 2006
Subcodes for BGP Cease 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. 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) The Internet Society (2006).
Abstract
This document defines several subcodes for the BGP Cease 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 several subcodes for the BGP Cease 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]
RFC 4486 BGP Cease Notification Message Subcodes April 2006
3. 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 De-configured
4 Administrative Reset
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
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,
as shown in Figure 1, where the meaning and use 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 send a NOTIFICATION message
with the Error Code Cease and the Error Subcode "Administrative
Shutdown".
If a BGP speaker decides to de-configure a peer, then the speaker
SHOULD send a NOTIFICATION message with the Error Code Cease and the
Error Subcode "Peer De-configured".
Chen & Gillet Standards Track [Page 2]
RFC 4486 BGP Cease Notification Message Subcodes April 2006
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 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 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
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