IPv6 Support for Generic Routing Encapsulation (GRE)
draft-pignataro-intarea-gre-ipv6-00

Intarea Working Group                                       C. Pignataro
Internet-Draft                                             Cisco Systems
Updates: 2784 (if approved)                                    R. Bonica
Intended status: Standards Track                        Juniper Networks
Expires: April 3, 2015                                September 30, 2014

          IPv6 Support for Generic Routing Encapsulation (GRE)
                  draft-pignataro-intarea-gre-ipv6-00

Abstract

   Generic Routing Encapsulation (GRE) can be used to carry any network
   layer protocol over any network layer protocol.  GRE procedures are
   specified for IPv4, used as either the payload or delivery protocol.
   However, GRE procedures are not specified for IPv6, used as either
   the payload or delivery protocol.

   This document specifies GRE procedures for IPv6, used as either the
   payload or delivery protocol, and updates RFC 2784.

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 [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 April 3, 2015.

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Copyright Notice

   Copyright (c) 2014 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
   (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
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   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.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IPv6 as a GRE Payload . . . . . . . . . . . . . . . . . . . .   3
   3.  IPv6 as a GRE Delivery Protocol . . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   Generic Routing Encapsulation (GRE) [RFC2784] [RFC2890] can be used
   to encapsulate and carry any network layer protocol (payload) over
   any network layer protocol (delivery).  GRE procedures are specified
   for IPv4 [RFC0791], used as either the payload or delivery protocol.
   However, GRE procedures are not specified for IPv6 [RFC2460], used as
   either the payload or delivery protocol.

   This document specifies GRE procedures for IPv6, used as either the
   payload or delivery protocol, and updates RFC 2784 [RFC2784].

1.1.  Terminology

   The following terms are specific to GRE and are modeled from
   [RFC2784]:

   o  GRE delivery header - an IPv4 or IPv6 header whose source address
      represents the GRE ingress node and whose destination address
      represents the GRE egress node.  The GRE delivery header
      encapsulates a GRE header.

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   o  GRE header - the GRE protocol header.  The GRE header is
      encapsulated by the GRE delivery header and encapsulates GRE
      payload.

   o  GRE payload packet - a network layer packet that needs to be
      encapsulated and delivered to some destination, and is
      encapsulated by the GRE header.

   The following terms are specific MTU discovery:

   o  path MTU (PMTU) - the minimum MTU of all the links in a path
      between a source node and a destination node.  If the source and
      destination node are connected through an equal cost multipath
      (ECMP), the PMTU is equal to the minimum LMTU of all links
      contributing to the multipath.

   o  Path MTU Discovery (PMTUD) - A procedure for dynamically
      discovering the PMTU between two nodes on the Internet.  PMTUD
      procedures for IPv6 are defined in [RFC1981].

2.  IPv6 as a GRE Payload

   When the GRE payload is IPv6, the Protocol Type field in the GRE
   header MUST be equal to 0x86DD.

3.  IPv6 as a GRE Delivery Protocol

   When the GRE delivery protocol is IPv6, the GRE header MAY
   immediately follow the GRE delivery header.  Alternatively, IPv6
   extension headers MAY be inserted between the GRE delivery header and
   the GRE header.  However, the IPv6 Destination Options Header MUST
   NOT be inserted between the GRE delivery header and the GRE header.

   If the GRE header immediately follows the GRE delivery header, the
   IPv6 Next Header field in GRE delivery packet MUST be equal to 47.
   If extension headers are inserted between the GRE delivery header and
   the GRE header, the Next Header field in the last IPv6 extension
   header MUST be equal to 47.

   Following guidance provided in Section 5 of [RFC2460], GRE ingress
   nodes SHOULD implement PMTUD, in order to discover and take advantage
   of PMTUs greater than the IPv6 required minimum (1280 octets).
   However, a GRE ingress node MAY simply restrict itself to sending
   packets no larger than 1280 octets, and omit implementation of PMTUD.

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4.  IANA Considerations

   This document makes no request of IANA.

5.  Security Considerations

   This document adds no additional security risks to GRE, beyond what
   is specified in [RFC2784].  It also does not provide any additional
   security for GRE.

6.  Acknowledgements

   The authors would like to thank Fred Baker and Andrew Yourtchenko for
   there thorough review and useful comments.

7.  Normative References

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791, September
              1981.

   [RFC1981]  McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery
              for IP version 6", RFC 1981, August 1996.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, December 1998.

   [RFC2784]  Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
              Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
              March 2000.

   [RFC2890]  Dommety, G., "Key and Sequence Number Extensions to GRE",
              RFC 2890, September 2000.

Authors' Addresses

   Carlos Pignataro
   Cisco Systems
   7200-12 Kit Creek Road
   Research Triangle Park, North Carolina  27709
   USA

   Email: cpignata@cisco.com

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   Ron Bonica
   Juniper Networks
   2251 Corporate Park Drive
   Herndon, Virginia
   USA

   Email: rbonica@juniper.net

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