Network working group F. Wei Internet Draft Z. Li Intended status: Standards Track China Mobile Expires: September 8, 2010 T. Li Cisco Systems, Inc. J. Dong Huawei Technologies March 8, 2010 New TLV for Purge Packet in Intermediate System to Intermediate System (IS-IS) Protocol draft-wei-isis-tlv-02.txt Abstract At present the purge packet does not contain information of the source Intermediate System (IS) generating it. Thus under the circumstance of purge packet propagation, it is difficult to traceback and locate the source IS. To address the problem, this document proposes to add a new TLV in purge packet to record the system ID of the IS generating it. This TLV should not be changed in purge packets sent by other ISs. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on September 8, 2010. Wei, et al. Expires September 8, 2010 [Page 1] Internet-Draft New TLV for Purge Packet in IS-IS March 2010 Copyright Notice Copyright (c) 2009 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 to this document. Table of Contents 1. Introduction.................................................2 2. Requirements Language........................................2 3. Cases to generate purge packet...............................3 4. Proposed New TLV in Purge Packet.............................3 5. Security Considerations......................................4 6. IANA Considerations..........................................4 7. Acknowledgments..............................................4 8. Normative References.........................................4 Authors' Addresses..............................................5 1. Introduction IS-IS [ISO 10589] routing protocol has been widely used in large- scale IP networks because of its strong scalability and fast speed of convergence. IS-IS is a kind of link-state routing protocol by flooding the Link State Protocol Data Unit (LSP) to advertise route network widely. 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 IS-IS protocol has no mechanism to traceback and locate the source when purge packet propagation does occur in the network. To address this problem, this document proposes to add a new TLV in purge packet to record the system ID of the IS generating it. 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]. Wei, et al. Expires September 8, 2010 [Page 2] Internet-Draft New TLV for Purge Packet in IS-IS March 2010 3. Cases to Generate Purge Packet The legitimate purge cases: (1) Originating IS purges its own LSP. (2) LSP owned by another IS ages out. (3) A new DIS is elected. The inappropriate purge cases: (1) An implementation misunderstanding [ISO 10589] generates purge packet when it receives corrupted LSP. (2) An implementation with bugs tries to self-purge and makes some truly egregious mistakes. (3) An implementation fails to retain the LSP header after purging while flooding is still in progress. 4. Proposed New TLV in Purge Packet This document proposes a new TLV for purge packet, which records the system ID of the IS generating the purge packet. This kind of TLV SHOULD not be changed in purge packets sent by other ISs than the initiator. The purpose to introduce this TLV is to traceback and locate the source IS that initiates the purge packet when purge packet propagation occurs in the network, which is usually caused by the inappropriate cases mentioned in above section of this document. This method is useful in both lab and field network. It is helpful for both developers and network operators. The new TLV is: CODE - XX (to be assigned) LENGTH - total length of the value field. VALUE - System ID of the Intermediate System that initiates the Purge packet. Wei, et al. Expires September 8, 2010 [Page 3] Internet-Draft New TLV for Purge Packet in IS-IS March 2010 5. Security Considerations If the proposed TLV is used in conjunction with IS-IS authentication mechanisms [RFC5304][RFC5310], the purge LSP is constructed by removing the original contents of the LSP, leaving only the LSP header, adding the proposed TLV and then adding the IS-IS authentication TLV. This document amends the behavior specified in [RFC5304] and [RFC5310]. 6. IANA Considerations A new code is solicited to be assigned to the proposed TLV. 7. Acknowledgments Many thanks to Adrian Farrel and Daniel King for their comments to improve this document and move it forward. The initial work by Yue Qin and Lianyuan Li is appreciated. 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. 8. 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. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [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. Wei, et al. Expires September 8, 2010 [Page 4] Internet-Draft New TLV for Purge Packet in IS-IS March 2010 Authors' Addresses Fang Wei China Mobile No. 29, Financial Street, Xicheng District Beijing 100032 P.R. China Email: weifang@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. Hai-Dian District Beijing, 100085 P.R. China EMail: dongjie_dj@huawei.com Wei, et al. Expires September 8, 2010 [Page 5]