Internet DRAFT - draft-guichard-metadata-header
draft-guichard-metadata-header
Network Working Group J. Guichard
Internet-Draft S. Spraggs
Intended status: Standards Track C. Pignataro, Ed.
Expires: December 14, 2013 S. Bryant
Cisco
June 12, 2013
Common Metadata Header Format for IP/MPLS Networks
draft-guichard-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
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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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This Internet-Draft will expire on December 14, 2013.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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 for his 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".
[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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