One document matched: draft-ietf-isis-reg-purge-01.txt

Differences from draft-ietf-isis-reg-purge-00.txt

IS-IS Working Group                                                T. Li
Internet-Draft                                               L. Ginsberg
Updates: 3563 5304 5310                              Cisco Systems, Inc.
(if approved)                                              March 1, 2011
Intended status: Standards Track
Expires: September 2, 2011


                  IS-IS Registry Extension for Purges
                      draft-ietf-isis-reg-purge-01

Abstract

   IANA maintains the IS-IS TLV Codepoint Registry.  This registry
   documents which TLVs can appear in different types of IS-IS Protocol
   Data Units (PDUs), but does not document which TLVs can be found in
   zero Remaining Lifetime Link State PDUs (LSPs, a.k.a., purges).  This
   document extends the existing registry to record the set of TLVs that
   are permissible in purges, and updates the rules for generating and
   processing purges in the presence of authentication.

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-
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   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 September 2, 2011.

Copyright Notice

   Copyright (c) 2011 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
   carefully, as they describe your rights and restrictions with respect



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   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.  Requirements Language . . . . . . . . . . . . . . . . . . . 3
   2.  Registry Changes  . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Purges and Authentication . . . . . . . . . . . . . . . . . . . 3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5



































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1.  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 (ISs) 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] [RFC5310], amend
   the process of generating a purge and allow the inclusion of certain
   TLVs in purges.

1.1.  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].


2.  Registry Changes

   This document extends the current IS-IS TLV Codepoint Registry,
   defined in [RFC3563], to record the set of TLVs that MAY be found in
   purges.  All other TLVs MUST NOT appear 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 implementers, providing them with an
   easily accessible compendium of allowable TLVs.

   The purge status defined for a given TLV applies to all sub-TLVs
   defined for that TLV.


3.  Purges and Authentication

   Previous documents on Authentication [RFC5304] [RFC5310] required
   that an IS only accept a purge if it only contained the
   Authentication TLV.

   This document updates and generalizes that behavior as follows: an
   implementation that implements Authentication MUST NOT accept a purge
   that contains any TLV listed in the registry that is not acceptable
   in a purge.  An implementation MUST NOT accept a purge that contains
   a TLV not listed in the registry unless the purge also contains the



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   Purge Originator Identification (POI) TLV [I-D.ietf-isis-purge-tlv].
   Purges that are accepted MUST be propagated without removal of TLVs.
   If multiple purges are received for the same LSP, then the
   implementation MAY propagate any one of the purges.

   If an implementation that implements Authentication accepts a purge
   that does not include the POI TLV and it chooses to insert the POI
   TLV, it MUST also recompute Authentication.

   ISs MUST NOT accept LSPs with a non-zero Remaining Lifetime that
   contain the POI TLV.

   Purge generation is updated as follows: an implementation that
   implements Authentication generates a purge by first removing any
   TLVs that are not listed in the registry as being acceptable in
   purges.  The POI TLV MUST be added.  Then any other TLVs that MAY be
   in purges, as shown by the registry, MAY be added.  Finally,
   Authentication, if any, is added.


4.  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 MAY be found in a
   purge.  A 'n' in this column indicates that the TLV for this row MUST
   NOT be found in a purge.

   The 'Purge' column should initially contain a 'y' for TLV type 10
   (Authentication) and for TLV type 137 (Dynamic hostname).  All other
   entries in this column should have an 'n'.  Other additions to this
   registry should explicitly specify their value for this column.


5.  Security Considerations

   This document introduces no new security issues.


6.  Normative References

   [I-D.ietf-isis-purge-tlv]
              Wei, F., Qin, Y., Li, Z., Li, T., and J. Dong, "Purge
              Originator Identification TLV for IS-IS",
              draft-ietf-isis-purge-tlv-05 (work in progress),
              October 2010.

   [ISO 10589]



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              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.

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

   [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.

   [RFC5310]  Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
              and M. Fanto, "IS-IS Generic Cryptographic
              Authentication", RFC 5310, February 2009.


Authors' Addresses

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

   Email: tony.li@tony.li


   Les Ginsberg
   Cisco Systems, Inc.
   170 W. Tasman Dr.
   San Jose, CA  95134
   USA

   Email: ginsberg@cisco.com












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