A Fragmentation Strategy for Generic Routing Encapsulation (GRE)
draft-bonica-intarea-gre-mtu-02

The information below is for an old version of the document
Document Type Active Internet-Draft (individual)
Last updated 2013-06-21
Replaced by rfc7588, draft-ietf-intarea-gre-mtu
Stream (None)
Intended RFC status (None)
Formats plain text pdf html bibtex
Additional URLs
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Intarea Working Group                                          R. Bonica
Internet-Draft                                          Juniper Networks
Intended status: Best Current Practice                      C. Pignataro
Expires: December 24, 2013                                 Cisco Systems
                                                           June 22, 2013

    A Fragmentation Strategy for Generic Routing Encapsulation (GRE)
                    draft-bonica-intarea-gre-mtu-02

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 24, 2013.

Copyright Notice

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

Bonica & Pignataro      Expires December 24, 2013               [Page 1]
Internet-Draft              GRE Fragmentation                  June 2013

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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  . . . . . . . . . . . . . . . . . . .   6
   3.  Generic Requirements for GRE Ingress Routers  . . . . . . . .   7
     3.1.  General . . . . . . . . . . . . . . . . . . . . . . . . .   7
     3.2.  Tunnel MTU (TMTU) Estimation and Discovery  . . . . . . .   7
   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 . . . . . . . . . . . . . . . . . . . . . .   9
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     9.2.  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
   fragmentation.  Lacking guidance from the specification, vendors have
   developed implementation-specific fragmentation strategies.  For the
   most part, devices implementing one fragmentation strategy can
Show full document text