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: March 5, April 27, 2011                              Cisco Systems, Inc.
                                                                 J. Dong
                                                     Huawei Technologies
                                                       September 1,
                                                        October 24, 2010

             Purge Originator Identification TLV for IS-IS


   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

   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 March 5, April 27, 2011.

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
   Provisions Relating to IETF Documents
   ( 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 (POI) TLV . . . . . . . . . 3
   4.  Using the Dynamic Hostname TLV in Purges  . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 4
   8.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5

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

   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",
   document are to be interpreted as described in [RFC2119].

3.  The Purge Originator Identification (POI) TLV

   This document defines a TLV to be included in purges.  If an IS
   generates a purge, it SHOULD include this TLV in the purge with its
   own system ID.  If an IS receives a purge that does not include this
   TLV, then it SHOULD add this TLV with both its own system ID and the
   system ID of the IS 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 POI TLV is defined as:

   CODE - 13

   LENGTH - total length of the value field.

   VALUE -
      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.

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

   The POI TLV SHOULD be found in all purges and MUST NOT be found in
   LSPs with a non-zero Remaining Lifetime.

4.  Using the Dynamic Hostname TLV in Purges

   This document also extends the use of the Dynamic hostname TLV (type
   137) [RFC5301] to further aid in the rapid identification of the
   system that generated the purge.  This TLV MAY be included in purges.
   Implementations SHOULD include the one instance of Dynamic hostname TLV
   if the POI TLV is included.  Only the local hostname should be

5.  Security Considerations

   Use of the extensions defined here with authentication as defined in
   [RFC5304] or [RFC5310] will result in the discarding of purges by
   legacy systems which are in strict conformance with either of those
   RFCs.  This may compromise the correctness/consistency of the routing
   database unless all ISs in the network support these extensions.  NEW
   Therefore, all implementations in a domain implementing
   authentication MUST be upgraded to receive the POI TLV before any IS
   is allowed to generate a purge with the POI TLV.

   More interactions between the POI TLV, the Dynamic hostname TLV, and
   the Authentication TLV are described in []. [I-D.ietf-isis-reg-purge].

6.  IANA Considerations

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

   This document requests that IANA assign code point 13 for the 'Purge
   Originator Identification' TLV from the IS-IS 'TLV Codepoints
   Registry'.  The additional values for this TLV should be: IIH:n,
   LSP:y, SNP:n, Purge:y.

7.  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

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

8.  Normative References


              Li, T., T. and L. Ginsberg, "IS-IS Registry Extension for
              draft-li-reg-purge-00 draft-ietf-isis-reg-purge-00 (work in progress), August
              October 2010.

   [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.

Authors' Addresses

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


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


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


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


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