IS-IS Registry Extension for Purges
draft-li-reg-purge-00

Abstract

IANA maintains the IS-IS TLV Codepoint Registry. This registry documents which TLVs can appear in different types of IS-IS PDUs, but does not document which TLVs can be found in zero Remaining Lifetime LSP (a.k.a., purges). This document extends the existing registry to record the set of TLVs that are permissible in purges.

Status of this Memo

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Table of Contents

1.  Introduction
2.  IANA Considerations
3.  Security Considerations
4.  Acknowledgments
5.  Informative References
§  Author's Address

1.  Introduction

The IS-IS [ISO 10589] (ISO, “Intermediate system to Intermediate system routeing information exchange protocol for use in conjunction with the Protocol for providing the Connectionless-mode Network Service (ISO 8473),” .) routing protocol maintains a link state database of the topology of its routing domain by flooding a set of Link State Protocol Data Units (LSPs). When the protocol no longer needs the information stored in an LSP, it uses the purge mechanism to cause the Intermediate Systems (ISes) in its domain to discard the information contained in the LSP. The process for generating purges can be found in Section 7.3.16.4 of [ISO 10589] (ISO, “Intermediate system to Intermediate system routeing information exchange protocol for use in conjunction with the Protocol for providing the Connectionless-mode Network Service (ISO 8473),” .). This process retains only the LSP header, discarding any TLVs that had been carried within the LSP.

Subsequent enhancements to IS-IS, such as [RFC5304] (Li, T. and R. Atkinson, “IS-IS Cryptographic Authentication,” October 2008.), amend the process of generating a purge and allow the inclusion of certain TLVs in purges.

This document extends the current IS-IS TLV Codepoint Registry, defined in [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,” July 2003.), to record the set of TLVs that can be found in purges. This will serve as an aid to subsequent documents, which can then refer to the registry as the definitive list of the TLVs allowed in purges. This will also act as an aid to implementors, providing them with an easily accessible compendium of allowable TLVs.

2.  IANA Considerations

This document requests that IANA modify the IS-IS 'TLV Codepoints Registry' by adding a column in the registry for 'Purge'. A 'y' in this column indicates that the TLV for this row can be found in a purge. A 'n' in this column indicates that the TLV for this row cannot be found in a purge.

The 'Purge' column should initially contain a 'y' for TLV type 10 (Authentication). All other entries in this column should have an 'n'.

3.  Security Considerations

This document introduces no new security issues.

4.  Acknowledgments

The author would like to thank Les Ginsberg for provoking this effort.

5. Informative References

Author's Address