Advertising Generic Information in IS-IS
RFC 6823
Internet Engineering Task Force (IETF) L. Ginsberg
Request for Comments: 6823 S. Previdi
Category: Standards Track M. Shand
ISSN: 2070-1721 Cisco Systems
December 2010
Advertising Generic Information in IS-IS
Abstract
This document describes the manner in which generic application
information (i.e., information not directly related to the operation
of the Intermediate System to Intermediate System (IS-IS) protocol)
should be advertised in IS-IS Link State Protocol Data Units (LSPs)
and defines guidelines that should be used when flooding such
information.
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/rfc6823.
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
(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.
Ginsberg, et al. Standards Track [Page 1]
RFC 6823 Advertising Generic Information in IS-IS December 2010
Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. Encoding Format for GENINFO . . . . . . . . . . . . . . . . . 3
3.1. GENINFO TLV . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Use of Sub-TLVs in GENINFO TLV . . . . . . . . . . . . . . 5
4. GENINFO Flooding Procedures . . . . . . . . . . . . . . . . . 5
4.1. Leaking Procedures . . . . . . . . . . . . . . . . . . . . 6
4.2. Minimizing Update Confusion . . . . . . . . . . . . . . . 7
4.3. Interpreting Attribute Information . . . . . . . . . . . . 7
5. Use of a Separate Protocol Instance . . . . . . . . . . . . . 7
6. Applicability of GENINFO TLV . . . . . . . . . . . . . . . . . 8
7. Standardization Requirements . . . . . . . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 9
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
11. Normative References . . . . . . . . . . . . . . . . . . . . . 10
1. Overview
[ISO10589] defines the format of Type-Length-Values (TLVs) that may
be sent in IS-IS Protocol Data Units (PDUs). The first octet of a
TLV encodes the "type" or "codepoint" that provides a scope for the
information and information format that follows. The protocol is
therefore limited to 256 different codepoints that may be assigned.
This number has proved generous as regards the information required
for correct operation of the IS-IS protocol. However, the increasing
use of IS-IS Link State Protocol Data Units (LSPs) for advertisement
of generic information (GENINFO) not directly related to the
operation of the IS-IS protocol places additional demands on the TLV
encoding space that have the potential to consume a significant
number of TLV codepoints. This document therefore defines an
encoding format for GENINFO that minimizes the consumption of TLV
codepoints and also maximizes the flexibility of the formats that can
be used to represent GENINFO.
This document also discusses optimal behavior associated with the
advertisement and flooding of LSPs containing GENINFO in order to
avoid the advertisement of stale information and minimize the
presence of duplicate or conflicting information when advertisements
are updated.
The manner in which the information contained in GENINFO TLVs is
exchanged between an instance of the IS-IS protocol and the
application that generates or consumes the GENINFO is outside the
scope of this specification.
Ginsberg, et al. Standards Track [Page 2]
Show full document text