A Fragmentation Strategy for Generic Routing Encapsulation (GRE)
draft-bonica-intarea-gre-mtu-03

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Replaced by rfc7588, draft-ietf-intarea-gre-mtu
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Intarea Working Group                                          R. Bonica
Internet-Draft                                          Juniper Networks
Intended status: Best Current Practice                      C. Pignataro
Expires: February 16, 2014                                 Cisco Systems
                                                                J. Touch
                                                                 USC/ISI
                                                         August 15, 2013

    A Fragmentation Strategy for Generic Routing Encapsulation (GRE)
                    draft-bonica-intarea-gre-mtu-03

Abstract

   This memo documents a GRE fragmentation strategy that has been
   implemented by many vendors and deployed in many networks.  It was
   written so that a) implementors will be aware of best common practice
   and b) those who rely on GRE will understand how implementations
   work.  The scope of this memo is limited to point-to-point GRE
   tunnels.  All other tunnel types are beyond the scope of this memo.

Requirements Language

   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 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on February 16, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Bonica, et al.          Expires February 16, 2014               [Page 1]
Internet-Draft              GRE Fragmentation                August 2013

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  How To Use This Document  . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Candidate Strategies and Strategic Overview . . . . . . . . .   5
     2.1.  Candidate Strategies  . . . . . . . . . . . . . . . . . .   5
     2.2.  Strategic Overview  . . . . . . . . . . . . . . . . . . .   7
   3.  Generic Requirements for GRE Ingress Routers  . . . . . . . .   8
     3.1.  General . . . . . . . . . . . . . . . . . . . . . . . . .   8
     3.2.  Tunnel MTU (TMTU) Estimation and Discovery  . . . . . . .   8
   4.  Procedures Affecting The GRE Deliver Header . . . . . . . . .   8
     4.1.  Tunneling GRE Over IPv4 . . . . . . . . . . . . . . . . .   8
     4.2.  Tunneling GRE Over IPv6 . . . . . . . . . . . . . . . . .   9
   5.  Procedures Affecting the GRE Payoad . . . . . . . . . . . . .   9
     5.1.  IPv4 Payloads . . . . . . . . . . . . . . . . . . . . . .   9
     5.2.  IPv6 Payloads . . . . . . . . . . . . . . . . . . . . . .   9
     5.3.  MPLS Payloads . . . . . . . . . . . . . . . . . . . . . .  10
   6.  GRE Egress Router Procedures  . . . . . . . . . . . . . . . .  10
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     10.2.  Informative References . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Generic Routing Encapsulation (GRE) [RFC2784] can be used to carry
   any network layer protocol over any network layer protocol.  GRE has
   been implemented by many vendors and is widely deployed on the
   Internet.

   [RFC2784], by design, does not describe procedures that affect
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