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 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 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 Guichard, et al. Expires March 31, 2014 [Page 1] Internet-Draft Metadata Format September 2013 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 . . . . . . . . . . . . . . . . . . . . . . . . . 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 Guichard, et al. Expires March 31, 2014 [Page 2] Internet-Draft Metadata Format September 2013 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 Guichard, et al. Expires March 31, 2014 [Page 3] Internet-Draft Metadata Format September 2013 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. Guichard, et al. Expires March 31, 2014 [Page 4] Internet-Draft Metadata Format September 2013 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 o Dan Frost 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 Guichard, et al. Expires March 31, 2014 [Page 5] Internet-Draft Metadata Format September 2013 (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 Guichard, et al. Expires March 31, 2014 [Page 6] Internet-Draft Metadata Format September 2013 Stewart Bryant Cisco Systems, Inc. 10 New Square Park Bedfont Lakes, Feltham TW14 8HA United Kingdom Email: stbryant@cisco.com Guichard, et al. Expires March 31, 2014 [Page 7]