Internet Engineering Task Force (IETF) T. Li
Request for Comments: 6233 L. Ginsberg
Updates: 3563, 5304, 5310 Cisco Systems, Inc.
Category: Standards Track May 2011
ISSN: 2070-1721
IS-IS Registry Extension for Purges
Abstract
IANA maintains the "IS-IS TLV Codepoints" registry. This registry
documents which TLVs can appear in different types of IS-IS Protocol
Data Units (PDUs), but does not document which TLVs can be found in
zero Remaining Lifetime Link State PDUs (LSPs), a.k.a. purges. This
document extends the existing registry to record the set of TLVs that
are permissible in purges and updates the rules for generating and
processing purges in the presence of authentication. This document
updates RFC 3563, RFC 5304, and RFC 5310.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6233.
Copyright Notice
Copyright (c) 2011 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. 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.
Li & Ginsberg Standards Track [Page 1]
RFC 6233 Registry Extension for Purges May 2011
Table of Contents
1. Introduction ....................................................2
1.1. Requirements Language ......................................2
2. Registry Changes ................................................2
3. Purges and Authentication .......................................3
4. IANA Considerations .............................................3
5. Security Considerations .........................................3
6. Normative References ............................................4
1. Introduction
The IS-IS [ISO-10589] routing protocol maintains a link state
database of the topology of its routing domain by flooding a set of
Link State Protocol Data Units (LSPs). When the protocol no longer
needs the information stored in an LSP, it uses the purge mechanism
to cause the Intermediate Systems (ISs) in its domain to discard the
information contained in the LSP. The process for generating purges
can be found in Section 7.3.16.4 of [ISO-10589]. This process
retains only the LSP header, discarding any TLVs that had been
carried within the LSP.
Subsequent enhancements to IS-IS, such as [RFC5304] [RFC5310], amend
the process of generating a purge and allow the inclusion of certain
TLVs in purges.
1.1. 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].
2. Registry Changes
This document extends the current "IS-IS TLV Codepoints" registry,
defined in [RFC3563], to record the set of TLVs that MAY be found in
purges. All other TLVs MUST NOT appear in purges. This will serve
as an aid to subsequent documents, which can then refer to the
registry as the definitive list of the TLVs allowed in purges. This
will also act as an aid to implementers, providing them with an
easily accessible compendium of allowable TLVs.
The purge status defined for a given TLV applies to all sub-TLVs
defined for that TLV.
Li & Ginsberg Standards Track [Page 2]
RFC 6233 Registry Extension for Purges May 2011
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