IS-IS Working Group                                                T. Li
Internet-Draft                                       Cisco Systems, Inc.
Updates: 3563 (if approved)                              August 13, 2010
Intended status: Informational
Expires: February 14, 2011


                  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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   This Internet-Draft will expire on February 14, 2011.

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   document authors.  All rights reserved.

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   described in the Simplified BSD License.


Table of Contents

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








































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.  Introduction

   The IS-IS [ISO 10589] 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].  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], 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], 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.


.  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'.


.  Security Considerations

   This document introduces no new security issues.


.  Acknowledgments

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





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.  Informative References

   [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)", ISO/IEC 10589:2002.

   [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.

   [RFC5304]  Li, T. and R. Atkinson, "IS-IS Cryptographic
              Authentication", RFC 5304, October 2008.


Author's Address

   Tony Li
   Cisco Systems, Inc.
   170 W. Tasman Dr.
   San Jose, CA  95134
   USA

   Email: tony.li@tony.li

























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