Updates to the IS-IS TLV Codepoints Registry
draft-ietf-isis-tlv-codepoints-02

Networking Working Group                                     L. Ginsberg
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                         August 14, 2014
Expires: February 15, 2015

                Updates to IS-IS TLV Codepoints Registry
                 draft-ietf-isis-tlv-codepoints-02.txt

Abstract

   This document recommends some editorial changes to the IANA IS-IS TLV
   Codepoints registry to more accurately document the state of the
   protocol.  It also sets out new guidelines for Designated Experts to
   apply when reviewing allocations from the registry.

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
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   This Internet-Draft will expire on February 15, 2015.

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   carefully, as they describe your rights and restrictions with respect
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IS Neighbor sub-TLV Registry  . . . . . . . . . . . . . . . .   3
   3.  Prefix Reachability sub-TLV Registry  . . . . . . . . . . . .   3
   4.  Guidance for Designated Experts . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     8.2.  Informational References  . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   The IS-IS TLV Codepoints registry was created by [RFC3563] and
   extended by [RFC6233].  The assignment policy for the registry is
   "Expert Review" as defined in [RFC5226].  As IS-IS related documents
   are developed, the codepoints required for the protocol extensions
   are reviewed by the Designated Experts and added to the IANA managed
   registry.  As these documents are published as RFCs, the registries
   are updated to reference the relevant RFC.

   In the case of TLVs supporting prefix advertisement, currently
   separate sub-TLV registries are maintained for each TLV.  These
   registries need to be combined into a common sub-TLV registry similar
   to what has been done for neighbor advertisement TLVs.

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   In some cases there is a need to allocate codepoints defined in
   Internet-Drafts which seem likely to eventually gain WG approval
   without waiting for those drafts to be published as RFCs.  This can
   be achieved using Expert Review, and this document sets out guidance
   for the Designated Experts to apply when reviewing allocations from
   the registry.

2.  IS Neighbor sub-TLV Registry

   There is an existing common sub-TLV registry for Sub-TLVs for TLV 22,
   141, and 222.  [RFC5311] defines the IS Neighbor Attribute TLV (23)
   and the MT IS Neighbor Attribute TLV (223).  Format of these TLVs is
   identical to TLVs 22 and 222 respectively.  The IS Neighbor sub-TLV
   Registry needs to be extended to include these two TLVs.  Settings
   for inclusion of each sub-TLV are identical to the settings for TLVs
   22 and 222 respectively.

3.  Prefix Reachability sub-TLV Registry

   Currently there exist separate sub-TLV registries for TLVs (135, 235,
   236, 237).  As in the case of the IS Neighbor TLVs discussed in the
   previous section, assignment of sub-TLVs applicable to one or more of
   these TLVs is intended to be common.  Therefore the existing separate
   sub-TLV registries need to be combined into a single registry
   entitled "Sub-TLVs for TLVs 135, 235, 236, and 237".  As existing
   sub-TLV assignments are common to all the TLVs this represents no
   change to the protocol - only a clearer representation of the
   intended sub-TLV allocation strategy.  Format of the registry would
   be as shown below:

   Type  Description                       135 235 236 237  Reference
   ----  ------------                      --- --- --- ---  ---------
   0     Unassigned
   1     32-bit Administrative Tag Sub-TLV  Y   Y   Y   Y   [RFC5130]
   2     64-bit Administrative Tag Sub-TLV  Y   Y   Y   Y   [RFC5130]
   3-255 Unassigned

4.  Guidance for Designated Experts

   When new drafts are introduced requiring new codepoints, it is
   advantageous to be able to allocate codepoints without waiting for
   them to progress to RFC.  The reasons this is advantageous are
   described in [RFC7120].  However, [RFC7120] procedures for early
   allocation do not apply to registries such as the IS-IS TLV
   Codepoints Registry which utilize "Expert Review" allocation policy.
   In such cases what is required is that a request be made to the

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   Designated Experts who MAY approve the assignments according to the
   guidance that has been established for the registry concerned.

   The following guidance applies specifically to the IS-IS TLV
   Codepoints registry.

   1.  Application for a codepoint allocation MAY be made to the
       Designated Experts at any time.

   2.  The Designated Experts SHOULD only consider requests that arise
       from Internet-Drafts that have already been accepted as Working
       Group documents or that are planned for progression as AD
       Sponsored documents in the absence of a suitably chartered
       Working Group.

   3.  In the case of Working Group documents, the Designated Experts
       SHOULD check with the Working Group chairs that there is
       consensus within the Working Group to make the allocation at this
       time.  In the case of AD Sponsored documents, the Designated
       Experts SHOULD check with the AD for approval to make the
       allocation at this time.

   4.  The Designated Experts SHOULD then review the assignment requests
       on their technical merit.  The Designated Experts SHOULD NOT seek
       to overrule IETF consensus, but MAY raise issues for further
       consideration before the assignments are made.

   5.  Once the Designated Experts have granted approval IANA will
       update the registry marking the allocated codepoints with a
       reference to the associated document as normal.

   6.  In the event that the document fails to progress to RFC the
       Expiry and deallocation process defined in [RFC7120] MUST be
       followed for the relevant code points - noting that the
       Designated Experts perform the role assigned to Working Group
       chairs.

5.  IANA Considerations

   This document provides guidance to the Designated Experts appointed
   to manage allocation requests in the IS-IS TLV Codepoints Registry.

   This document requires the addition of TLVs 23 and 223 to the
   existing Sub-TLVs for TLV 22, 141, and 222 registry as described in
   Section 2.

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   This document requires the existing sub-TLV registries for TLVs (135,
   235, 236, 237) be combined into a single registry as described in
   Section 3.

6.  Security Considerations

   This document introduces no new security issues.

7.  Acknowledgements

   The author wishes to thank Alia Atlas and Amanda Baber for their
   input in defining the correct process to follow to get these changes
   implemented.  Special thanks to Adrian Farrel for crafting the text
   in Section 4.

8.  References

8.1.  Normative References

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

   [RFC5130]  Previdi, S., Shand, M., and C. Martin, "A Policy Control
              Mechanism in IS-IS Using Administrative Tags", RFC 5130,
              February 2008.

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

   [RFC5311]  McPherson, D., Ginsberg, L., Previdi, S., and M. Shand,
              "Simplified Extension of Link State PDU (LSP) Space for
              IS-IS", RFC 5311, February 2009.

   [RFC6233]  Li, T. and L. Ginsberg, "IS-IS Registry Extension for
              Purges", RFC 6233, May 2011.

   [RFC7120]  Cotton, M., "Early IANA Allocation of Standards Track Code
              Points", BCP 100, RFC 7120, January 2014.

8.2.  Informational References

   [RFC3563]  Zinin, A., "Cooperative Agreement Between the ISOC/IETF
              and ISO/IEC Joint Technical Committee 1/Sub Committee 6
              (JTC1/SC6) on IS-IS Routing Protocol Development", RFC
              3563, July 2003.

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Author's Address

   Les Ginsberg
   Cisco Systems
   510 McCarthy Blvd.
   Milpitas, CA  95035
   USA

   Email: ginsberg@cisco.com

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