draft-ietf-isis-purge-tlv-03.txt   draft-ietf-isis-purge-tlv-04.txt 
IS-IS Working Group F. Wei IS-IS Working Group F. Wei
Internet-Draft Y. Qin Internet-Draft Y. Qin
Updates: 5301, 5304, 5310 Z. Li Updates: 5301 5304 5310 Z. Li
(if approved) China Mobile (if approved) China Mobile
Intended status: Standards Track T. Li Intended status: Standards Track T. Li
Expires: December 17, 2010 Cisco Systems, Inc. Expires: March 5, 2011 Cisco Systems, Inc.
J. Dong J. Dong
Huawei Technologies Huawei Technologies
June 15, 2010 September 1, 2010
Purge Originator Identification TLV for IS-IS Purge Originator Identification TLV for IS-IS
draft-ietf-isis-purge-tlv-03 draft-ietf-isis-purge-tlv-04
Abstract Abstract
At present an IS-IS purge does not contain any information At present an IS-IS purge does not contain any information
identifying the Intermediate System (IS) that generates the purge. identifying the Intermediate System (IS) that generates the purge.
This makes it difficult to locate the source IS. This makes it difficult to locate the source IS.
To address this issue, this document defines a TLV to be added to 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 purges to record the system ID of the IS generating it. Since normal
LSP flooding does not change LSP contents, this TLV should propagate LSP flooding does not change LSP contents, this TLV should propagate
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 17, 2010. This Internet-Draft will expire on March 5, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language . . . . . . . . . . . . . . . . . . . . . 3
3. The Purge Originator Identification TLV . . . . . . . . . . . . 3 3. The Purge Originator Identification (POI) TLV . . . . . . . . . 3
4. Using the Dynamic Hostname TLV in Purges . . . . . . . . . . . 4 4. Using the Dynamic Hostname TLV in Purges . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
6. Functional Changes . . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 8. Normative References . . . . . . . . . . . . . . . . . . . . . 5
9. Normative References . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
The IS-IS [ISO 10589] routing protocol has been widely used in large- The IS-IS [ISO 10589] routing protocol has been widely used in large-
scale IP networks because of its strong scalability and fast scale IP networks because of its strong scalability and fast
convergence. convergence.
The IS-IS protocol floods purges throughout an area, regardless of The IS-IS protocol floods purges throughout an area, regardless of
which IS initiated the purge. If a network operator would like to which IS initiated the purge. If a network operator would like to
investigate the cause of the purge, it is difficult to determine the investigate the cause of the purge, it is difficult to determine the
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improperly generate a purge. These are all due to implementation improperly generate a purge. These are all due to implementation
deficiencies or implementations that predate [ISO TC1] and generate a deficiencies or implementations that predate [ISO TC1] and generate a
purge when they receive a corrupted LSP. purge when they receive a corrupted LSP.
2. Requirements Language 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
3. The Purge Originator Identification TLV 3. The Purge Originator Identification (POI) TLV
This document defines a TLV to be included in purges. If an IS 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 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 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 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. 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
This allows ISs receiving purges to log the system ID of the upstream source of the purge. This makes it much easier for the
originator, or the upstream source of the purge. This makes it much network administrator to locate the origin of the purge and thus the
easier for the network administrator to locate the origin of the cause of the purge. Similarly, this TLV is helpful to developers in
purge and thus the cause of the purge. Similarly, this TLV is lab situations.
helpful to developers in lab situations.
The Purge Originator Identification TLV is defined as: The POI TLV is defined as:
CODE - 13 CODE - 13
LENGTH - total length of the value field. LENGTH - total length of the value field.
VALUE - VALUE -
Number of system IDs carried in this TLV (1 octet) -- Only the Number of system IDs carried in this TLV (1 octet) -- Only the
values 1 and 2 are defined. values 1 and 2 are defined.
System ID of the Intermediate System that inserted this TLV. System ID of the Intermediate System that inserted this TLV.
System ID of the Intermediate System that the purge was received System ID of the Intermediate System that the purge was received
from. (optional) 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 4. Using the Dynamic Hostname TLV in Purges
This document also extends the use of the Dynamic hostname TLV (type This document also extends the use of the Dynamic hostname TLV (type
137) [RFC5301]. This TLV MAY also be included in purges. This will 137) [RFC5301] to further aid in the rapid identification of the
further aid in the rapid identification of the system that generated system that generated the purge. This TLV MAY be included in purges.
the purge. Implementations SHOULD include the Dynamic hostname TLV if the POI
TLV is included.
Implementations SHOULD include the Purge Originator Identification
TLV in addition to the Dynamic hostname TLV.
5. Security Considerations 5. Security Considerations
If the Purge Originator Identification TLV or the Dynamic hostname Use of the extensions defined here with authentication as defined in
TLV is used in conjunction with IS-IS authentication mechanisms [RFC5304] or [RFC5310] will result in the discarding of purges by
[RFC5304][RFC5310], the purge LSP is constructed or modified as legacy systems which are in strict conformance with either of those
follows. First, the original contents of the LSP are removed, RFCs. This may compromise the correctness/consistency of the routing
leaving only the LSP header, then the Purge Originator Identification database unless all ISs in the network support these extensions. NEW
TLV and/or the Dynamic hostname TLV are added, and then the IS-IS TEXT: Therefore, all implementations in a domain implementing
authentication TLV is added. authentication MUST be upgraded to receive the POI TLV before any IS
is allowed to generate a purge with the POI TLV.
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] More interactions between the POI TLV, the Dynamic hostname TLV, and
and [RFC5310]. ISs that receive purges with the Purge Originator the Authentication TLV are described in [I-D.li-reg-purge].
Identification TLV or the Dynamic hostname TLV with valid
authentication MUST NOT discard the PDU and SHOULD process it
normally. 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.
7. IANA Considerations 6. IANA Considerations
RFC EDITOR NOTE: This section to be removed upon publication. RFC EDITOR NOTE: This section to be removed upon publication.
This document requests that IANA assign a code point for this TLV This document requests that IANA assign code point 13 for the 'Purge
from the IS-IS 'TLV Codepoints Registry'. 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.
8. Acknowledgments 7. Acknowledgments
Many thanks to Adrian Farrel and Daniel King for your comments to Many thanks to Adrian Farrel and Daniel King for your comments to
improve this document and move it forward. improve this document and move it forward.
The first version of this document was mainly composed by Lianyuan The first version of this document was mainly composed by Lianyuan
Li. Li.
Acknowledgments to the discussion in the mailing list. Some Acknowledgments to the discussion in the mailing list. Some
improvements of this document are based on the discussion. improvements of this document are based on the discussion.
9. Normative References 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 10589]
ISO, "Intermediate system to Intermediate system routeing ISO, "Intermediate system to Intermediate system routeing
information exchange protocol for use in conjunction with information exchange protocol for use in conjunction with
the Protocol for providing the Connectionless-mode Network the Protocol for providing the Connectionless-mode Network
Service (ISO 8473)", ISO/IEC 10589:2002. Service (ISO 8473)", ISO/IEC 10589:2002.
[ISO TC1] ISO, "Intermediate system to Intermediate system intra- [ISO TC1] ISO, "Intermediate system to Intermediate system intra-
domain routeing information exchange protocol for use in domain routeing information exchange protocol for use in
conjunction with the protocol for providing the conjunction with the protocol for providing the
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