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Versions: 00 01 02 03 draft-ietf-v6ops-cidr-prefix

6man Working Group                                          M. Boucadair
Internet-Draft                                            France Telecom
Intended status: Standards Track                           June 23, 2014
Expires: December 25, 2014


        IPv6 Prefix Length Recommendation for Routing Protocols
              draft-boucadair-6man-prefix-routing-reco-00

Abstract

   The length of IP prefixes to be manipulated by forwarding and routing
   processes is policy-based; no maximum length must be assumed by
   design.  This document sketches a recommendation to be followed by
   forwarding and routing designs with regards to the prefix length.
   The aim is to avoid hard-coded routing and forwarding designs that
   exclude some IP prefix lengths.

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 25, 2014.

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



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Internet-Draft                                                 June 2014


   (http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Recommendation  . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   3
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   3
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   3

1.  Introduction

   Recent discussions on the 64-bit boundary in IPv6 addressing
   ([I-D.ietf-6man-why64]) revealed a need for a clear recommendation on
   which bits must be used by routing protocols (including route
   decision-making processes).

   A detailed analysis of the 64-bit boundary in IPv6 addressing, and
   the implication for end-side prefix assignment, is documented in
   [I-D.ietf-6man-why64].  No recommendation is included in
   [I-D.ietf-6man-why64].

   It is fundamental to not link routing and forwarding to the IPv6
   prefix/address semantic [RFC4291].  This document includes a
   recommendation for that aim.

2.  Recommendation

   Forwarding and routing protocols MUST NOT restrict by design the
   length of IPv6 prefixes.  In particular, forwarding and routing
   processes MUST be designed to accept prefixes of any length up to
   /128.

   Obviously, policies can be enforced to restrict the length of IP
   prefixes advertised within a given domain or in a given
   interconnection link.  These policies are deployment-specific and/or
   driven by administrative (interconnection) considerations.





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Internet-Draft                                                 June 2014


   This recommendation does not conflict with the 64-bit boundary
   followed for end-side prefix assignments.

3.  IANA Considerations

   This document does not require any action from IANA.

4.  Security Considerations

   This document does not introduce security issues in addition to what
   is discussed in [RFC4291].

5.  References

5.1.  Normative References

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

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

5.2.  Informative References

   [I-D.ietf-6man-why64]
              Carpenter, B., Chown, T., Gont, F., Jiang, S., Petrescu,
              A., and A. Yourtchenko, "Analysis of the 64-bit Boundary
              in IPv6 Addressing", draft-ietf-6man-why64-01 (work in
              progress), May 2014.

Author's Address

   Mohamed Boucadair
   France Telecom
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com













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