RFC 2890 (rfc2890) - Page 1 of 7

Key and Sequence Number Extensions to GRE

Network Working Group                                          G. Dommety
Request for Comments: 2890                                  Cisco Systems
Category: Standards Track                                  September 2000


               Key and Sequence Number Extensions to GRE

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 (2000).  All Rights Reserved.

Abstract

   GRE (Generic Routing Encapsulation) specifies a protocol for
   encapsulation of an arbitrary protocol over another arbitrary network
   layer protocol. This document describes extensions by which two
   fields, Key and Sequence Number, can be optionally carried in the GRE
   Header [1].

1. Introduction

   The current specification of Generic Routing Encapsulation [1]
   specifies a protocol for encapsulation of an arbitrary protocol over
   another arbitrary network layer protocol. This document describes
   enhancements by which two fields, Key and Sequence Number, can be
   optionally carried in the GRE Header [1]. The Key field is intended
   to be used for identifying an individual traffic flow within a
   tunnel. The Sequence Number field is used to maintain sequence of
   packets within the GRE Tunnel.

1.1. Specification Language


   The keywords "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 [3].

   In addition, the following words are used to signify the requirements
   of the specification.




Dommety                     Standards Track