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, 2011 Cisco Systems, Inc.
J. Dong
Huawei Technologies
September 1, 2010
Purge Originator Identification TLV for IS-IS
draft-ietf-isis-purge-tlv-04
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
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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 March 5, 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
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Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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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
8. Normative References . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5
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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 (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 -
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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.
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 Dynamic hostname TLV if the POI
TLV is included.
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
TEXT: 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.li-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.
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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
Li.
Acknowledgments to the discussion in the mailing list. Some
improvements of this document are based on the discussion.
8. Normative References
[I-D.li-reg-purge]
Li, T., "IS-IS Registry Extension for Purges",
draft-li-reg-purge-00 (work in progress), August 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.
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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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