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Versions: 00 01 02 03 04 05 RFC 6232

IS-IS Working Group                                               F. Wei
Internet-Draft                                                    Y. Qin
Updates: 5301, 5304, 5310                                          Z. Li
(if approved)                                               China Mobile
Intended status: Standards Track                                   T. Li
Expires: November 15, 2010                           Cisco Systems, Inc.
                                                                 J. Dong
                                                     Huawei Technologies
                                                            May 14, 2010


             Purge Originator Identification TLV for IS-IS
                      draft-ietf-isis-purge-tlv-01

Abstract

   At present an IS-IS purge does not contain any information
   identifying the Intermediate System (IS) that generates the purge.
   This makes it difficult to locate the source IS.

   To address this issue, this document defines a TLV to be added to
   purges to record the system ID of the IS generating it.  Since normal
   LSP flooding does not change LSP contents, this TLV should propagate
   with the purge.

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-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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 November 15, 2010.

Copyright Notice

   Copyright (c) 2010 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



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   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
   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
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . . . 3
   3.  The Purge Originator Identification TLV . . . . . . . . . . . . 3
   4.  Using the Dynamic Hostname TLV in Purges  . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  Functional Changes  . . . . . . . . . . . . . . . . . . . . . . 4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
   9.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 6





























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1.  Introduction

   The IS-IS [ISO 10589] routing protocol has been widely used in large-
   scale IP networks because of its strong scalability and fast
   convergence.

   The IS-IS protocol floods purges throughout an area, regardless of
   which IS initiated the purge.  If a network operator would like to
   investigate the cause of the purge, it is difficult to determine the
   origin of the purge.  At present the IS-IS protocol has no mechanism
   to locate the originator of a purge.  To address this problem, this
   document defines a TLV to be added to purges to record the system ID
   of the IS generating the purge.

   Field experience has observed several circumstances where an IS can
   improperly generate a purge.  These are all due to implementation
   deficiencies or implementations that predate [ISO TC1] and generate a
   purge when they receive a corrupted LSP.


2.  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].


3.  The Purge Originator Identification TLV

   This document defines a TLV to be included in purges.  This TLV
   carries the system ID of the IS generating the purge, or, in a proxy
   mode, carries the system ID of the IS that first saw the purge and
   inserted this TLV, as well as the system ID of the system that it
   received the purge from.

   This allows ISs receiving purges to log the system ID of the
   originator, or the upstream source of the purge.  This makes it much
   easier for the network administrator to locate the origin of the
   purge and thus the cause of the purge.  Similarly, this TLV is
   helpful to developers in lab situations.

   The Purge Originator Identification TLV is defined as:

   CODE - XX (to be assigned)

   LENGTH - total length of the value field.

   VALUE -



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      Number of system IDs carried in this TLV (1 octet) -- Only the
      values 1 and 2 are defined.

      System ID of the Intermediate System that inserted this TLV.

      The system ID of the Intermediate System that the purge was
      received from. (optional)


4.  Using the Dynamic Hostname TLV in Purges

   This document also extends the use of the Dynamic hostname TLV (type
   137) [RFC5301].  This TLV MAY also be included in purges.  This will
   further aid in the rapid identification of the system that generated
   the purge.

   Implementations SHOULD include the Purge Originator Identification
   TLV in addition to the Dynamic hostname TLV.


5.  Security Considerations

   If the proposed TLV or the Dynamic hostname TLV is used in
   conjunction with IS-IS authentication mechanisms [RFC5304][RFC5310],
   the purge LSP is constructed as follows.  First, the original
   contents of the LSP are removed, leaving only the LSP header, then
   the Purge Originator Identification TLV and/or the Dynamic hostname
   TLV are added, and then the IS-IS authentication TLV is added.

   Legacy systems that implement [RFC5304] or [RFC5310] MUST discard
   purges with these additional TLVs.  This is not thought to be a
   significant operational issue as the loss of purges is typically not
   critical.


6.  Functional Changes

   This document amends the behavior specified in [RFC5301], [RFC5304]
   and [RFC5310].  ISs that receive purges with the Purge Originator
   Identification TLV or the Dynamic hostname TLV with valid
   authentication MUST NOT discard the PDU and SHOULD process it
   normally.  ISs that receive purges with the Purge Originator
   Identification TLV or the Dynamic hostname TLV MUST be accepted and
   processed as a normal purge.  The Purge Originator Identification TLV
   or Dynamic hostname TLV MUST NOT be removed from the purge prior to
   propagation.  If multiple purges are received for the same LSP
   fragment, then the implementation MAY propagate any one of the
   purges.



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7.  IANA Considerations

   RFC EDITOR NOTE: This section to be removed upon publication.

   This document requests that IANA assign a code point for this TLV
   from the IS-IS 'TLV Codepoints Registry'.


8.  Acknowledgments

   Many thanks to Adrian Farrel and Daniel King for your comments to
   improve this document and move it forward.

   The first version of this document was mainly composed by Lianyuan
   Li.

   Acknowledgments to the discussion in the mailing list.  Some
   improvements of this document are based on the discussion.


9.  Normative 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.

   [ISO TC1]  ISO, "Intermediate system to Intermediate system intra-
              domain routeing information exchange protocol for use in
              conjunction with the protocol for providing the
              connectionless-mode Network Service (ISO 8473) --
              Technical Corrigendum 1", ISO/IEC 10589:1992/ Cor.1:1993.

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

   [RFC5301]  McPherson, D. and N. Shen, "Dynamic Hostname Exchange
              Mechanism for IS-IS", RFC 5301, October 2008.

   [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.





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Authors' Addresses

   Fang Wei
   China Mobile
   No. 29, Financial Street, Xicheng District
   Beijing  100032
   P.R. China

   Email: weifang@chinamobile.com


   Yue Qin
   China Mobile
   No. 29, Financial Street, Xicheng District
   Beijing  100032
   P.R. China

   Email: qinyue@chinamobile.com


   Zhenqiang Li
   China Mobile
   Unit2, Dacheng Plaza, No. 28 Xuanwumenxi Ave, Xuanwu District
   Beijing  100053
   P.R. China

   Email: lizhenqiang@chinamobile.com


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

   Email: tony.li@tony.li


   Jie Dong
   Huawei Technologies
   KuiKe Building, No.9 Xinxi Rd., Haidian District
   Beijing  100085
   P.R. China

   Email: dongjie_dj@huawei.com






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