Revised Error Handling for BGP UPDATE Messages
draft-ietf-idr-error-handling-03

Internet Engineering Task Force (IETF)                        J. Scudder
Internet Draft                                          Juniper Networks
Update: 1997, 4271, 4360, 5701 (if approved)                     E. Chen
Intended Status: Standards Track                            P. Mohapatra
Expires: May 22, 2013                                           K. Patel
                                                           Cisco Systems
                                                       November 21, 2012

             Revised Error Handling for BGP UPDATE Messages
                  draft-ietf-idr-error-handling-03.txt

Abstract

   According to the base BGP specification, a BGP speaker that receives
   an UPDATE message containing a malformed attribute is required to
   reset the session over which the offending attribute was received.
   This behavior is undesirable as a session reset would impact not only
   routes with the offending attribute, but also other valid routes
   exchanged over the session.  This document partially revises the
   error handling for UPDATE messages, and provides guidelines for the
   authors of documents defining new attributes.  Finally, it revises
   the error handling procedures for a number of existing attributes.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
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   This Internet-Draft will expire on May 22, 2013.

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Internet Draft    draft-ietf-idr-error-handling-03.txt         Nov. 2012

Copyright Notice

   Copyright (c) 2012 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
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   described in the Simplified BSD License.

1. Introduction

   According to the base BGP specification [RFC4271], a BGP speaker that
   receives an UPDATE message containing a malformed attribute is
   required to reset the session over which the offending attribute was
   received.  This behavior is undesirable as a session reset would
   impact not only routes with the offending attribute, but also other
   valid routes exchanged over the session.  In the case of optional
   transitive attributes, the behavior is especially troublesome and may
   present a potential security vulnerability.  The reason is that such
   attributes may have been propagated without being checked by
   intermediate routers that do not recognize the attributes -- in
   effect the attribute may have been tunneled, and when they do reach a
   router that recognizes and checks them, the session that is reset may
   not be associated with the router that is at fault.

   The goal for revising the error handling for UPDATE messages is to
   minimize the impact on routing by a malformed UPDATE message, while
   maintaining protocol correctness to the extent possible.  This can be
   achieved largely by maintaining the established session and keeping
   the valid routes exchanged, but removing the routes carried in the
   malformed UPDATE from the routing system.

   This document partially revises the error handling for UPDATE
   messages, and provides guidelines for the authors of documents
   defining new attributes.  Finally, it revises the error handling
   procedures for a number of existing attributes.  Specifically, the
   error handling procedures of [RFC4271], [RFC1997], [RFC4360] and
   [RFC5701] are revised.

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Internet Draft    draft-ietf-idr-error-handling-03.txt         Nov. 2012

1.1. Specification of Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",