Networking Working Group L. Ginsberg
Internet-Draft Cisco Systems
Intended status: Standards Track June 11, 2014
Expires: December 13, 2014

Updates to IS-IS TLV Codepoints Registry


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 defines early allocation procedures for codepoints managed by 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.

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This Internet-Draft will expire on December 13, 2014.

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Table of Contents

1. Introduction

The IS-IS TLV Codepoints registry was created by [RFC3563] and extended by [RFC6233]. As IS-IS related RFCs are published the codepoints required for the protocol extensions are added to the IANA managed registry. In the case of TLVs supporting neighbor advertisement a common sub-TLV registry has been created. This sub-TLV registry needs to include additional neighbor advertisement TLVs defined in [RFC5311].

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.

There is a need to support early allocation of codepoints defined in drafts which seem likely to eventually gain WG approval. The procedure for obtaining early allocation of codepoints is described.

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]
1     64-bit Administrative Tag Sub-TLV  Y   Y   Y   Y   [RFC5130]
3-255 Unassigned

4. Early Allocation of Codepoints

When new drafts are introduced requiring new codepoints, it is advantageous to have the ability to do early allocation of codepoints. The reasons this is advantageous and the process to do so is described in [RFC7120]. However, [RFC7120] procedures 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 designated experts. The following procedures are defined. Note these procedures apply specifically to the IS-IS TLV Codepoints registry. This document is not defining a general early allocation process for other Expert Review registries.

  1. In order to qualify for early allocation a draft MUST be accepted as a WG document
  2. The author(s) of the draft MAY request early allocation of codepoints to the chair(s) of the WG in which the document is submitted
  3. The WG chair(s) gauge whether there is consensus within the WG that early allocation is appropriate for the given document and that the conditions for early allocation specified in [RFC7120] Section 2 are satisfied. If so the request is forwarded to the Area Director(s).
  4. If the Area Director(s) approve, the request is forwarded to the Designated Experts for their approval.
  5. Once the Designated Experts have granted approval IANA will update the registry marking the allocated codepoints as "Temporary" following the procedures specified in [RFC7120] Section 3.1

5. IANA Considerations

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.

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.

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.
[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.

Author's Address

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