Internet DRAFT - draft-guichard-sfc-metadata-header

draft-guichard-sfc-metadata-header






Network Working Group                                        J. Guichard
Internet-Draft                                                S. Spraggs
Intended status:  Standards Track                      C. Pignataro, Ed.
Expires:  March 31, 2014                                       S. Bryant
                                                                   Cisco
                                                      September 27, 2013


           Common Metadata Header Format for IP/MPLS Networks
                 draft-guichard-sfc-metadata-header-00

Abstract

   This document defines the common format for the metadata header used
   to carry metadata in IPv4, IPv6, and MPLS packets.

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
   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
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   time.  It is inappropriate to use Internet-Drafts as reference
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   This Internet-Draft will expire on March 31, 2014.

Copyright Notice

   Copyright (c) 2013 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



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   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
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Metadata Component Structure  . . . . . . . . . . . . . . . . . 3
   3.  Metadata Channel Header Format  . . . . . . . . . . . . . . . . 4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   6.  Contributing Authors  . . . . . . . . . . . . . . . . . . . . . 5
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     8.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     8.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 6






























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1.  Introduction

   This document defines a common header format that is used in IPv4,
   IPv6 and MPLS packets to carry metadata in addition to the payload.
   The format of specific metadata types and how the metadata is used is
   outside the scope of this document.  Anticipated uses of metadata
   include instrumentation of user data frames and service chaining.

   Mechanisms for identification of the presence of metadata within an
   IPv4, IPv6, or MPLS packet are addressed in separate documents
   [I-D.guichard-mpls-metadata].

1.1.  Terminology

   ACH   Associated Channel Header

   MCH   Metadata Channel Header

   MD    Metadata


2.  Metadata Component Structure

   The structure of the metadata component is common for IPv4, IPv6, and
   MPLS encapsulations.  It is comprised of a Header and a channel
   carrying Metadata, and is followed by the original packet payload.
   Figure 1 shows the complete structure:

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                Metadata Channel Header (MCH)                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                 Metadata Channel (variable)                   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                     Original Payload                          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 1: Metadata Component Structure

   The meanings of the metadata components are:

   o  Metadata Channel Header (MCH):  common header used for IPv4, IPv6,
      and MPLS packets to indicate the type and structure of the
      metadata carried within the packet.

   o  Metadata Channel:  the actual metadata.  The length and format of
      the metadata channel is outside the scope of this document and



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      will vary depending upon the "Metadata Channel Type" specified in
      the MCH.  It is anticipated that there will be a number of
      instrumentation channels, as well as channels for functionality.

   o  Original Payload:  beneath the metadata will be the original
      packet payload.  This could be L3, L2 or MPLS payload.


3.  Metadata Channel Header Format

   The Metadata Channel Header (MCH) is similar in structure to the
   Associated Channel Header (ACH) as defined in [RFC5586].  The type
   and format of the actual metadata is defined in other documents.

   The proposed format of the MCH is as depicted in Figure 2:

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 0 0|Version|    Protocol   |    Metadata Channel Type      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 2: Metadata Channel Header Format

   The meanings of the fields in the MCH are:

   o  First Nibble:  it is set to 0000b to indicate a Metadata Channel
      associated with IPv4, IPv6, or MPLS.

   o  Version:  version number of the metadata channel.  This
      specification defines a value of 0.

   o  Protocol:  Where the network layer is MPLS this MUST be set to a
      value of 0 and ignored on reception.  Where the network layer is
      IPv4 [RFC0791] this carries the protocol number that identifies
      the protocol that follows the metadata, i.e. it contains the
      protocol number that would have been in the IP header if the
      metadata had not been inserted.  Similarly if the network layer is
      IPv6 [RFC2460] this is the final next-header value that would have
      been present if the metadata had not been inserted.

   o  Metadata Channel Type:  The Metadata Channel Type is defined in
      the IANA Metadata Channel Type registry Section 4.








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4.  IANA Considerations

   This document request IANA to create and maintain the "Metadata
   Channel Type" registry.  Registry entries are assigned by using the
   "IETF Review" policy defined in [RFC5226].

   IANA are requested to initally mark the registry as follows:
   Value               Description
   -----------------+-------------------------------
   0x0000              Reserved
   0x0001 - 0x7FF7     Unassigned
   0x7ff8 - 0x7FF7     Reserved for Experimental Use
   0x8000 - 0xFFFF     Unassigned


5.  Security Considerations

   The security considerations associated with the addition of metadata
   to packets are discussed in the network layer specific documents
   [I-D.guichard-mpls-metadata].  The security risks associated with
   each metadata type that is defined MUST be documented as part of the
   definition.


6.  Contributing Authors

   o  Clarence Filsfils <cfilsfil@cisco.com>

   o  Dan Frost <danfrost@cisco.com>


7.  Acknowledgments

   The authors would like to thank Giles Heron and Tom Nadeau for their
   review and useful comments.


8.  References

8.1.  Normative References

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

   [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



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              (IPv6) Specification", RFC 2460, December 1998.

8.2.  Informative References

   [I-D.guichard-mpls-metadata]
              Guichard, J., Pignataro, C., Spraggs, S., and S. Bryant,
              "Carrying Metadata in MPLS Networks",
              draft-guichard-mpls-metadata-00 (work in progress),
              June 2013.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

   [RFC5586]  Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
              Associated Channel", RFC 5586, June 2009.


Authors' Addresses

   Jim Guichard
   Cisco Systems, Inc.

   Email:  jguichar@cisco.com


   Simon Spraggs
   Cisco Systems, Inc.
   10 New Square Park
   Bedfont Lakes, Feltham  TW14 8HA
   United Kingdom

   Email:  sspraggs@cisco.com


   Carlos Pignataro (editor)
   Cisco Systems, Inc.
   7200-12 Kit Creek Road
   Research Triangle Park, NC  27709
   US

   Email:  cpignata@cisco.com









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   Stewart Bryant
   Cisco Systems, Inc.
   10 New Square Park
   Bedfont Lakes, Feltham  TW14 8HA
   United Kingdom

   Email:  stbryant@cisco.com












































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