IS-IS Route Preference for Extended IP and IPv6 Reachability
RFC 7775
| Document | Type |
RFC - Proposed Standard
(February 2016; No errata)
Updates RFC 5308
|
|
|---|---|---|---|
| Last updated | 2016-02-29 | ||
| Replaces | draft-ginsberg-isis-route-preference | ||
| Stream | IETF | ||
| Formats | plain text pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Christian Hopps | ||
| Shepherd write-up | Show (last changed 2015-10-01) | ||
| IESG | IESG state | RFC 7775 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Alia Atlas | ||
| Send notices to | (None) | ||
| IANA | IANA review state | IANA OK - No Actions Needed | |
| IANA action state | No IANA Actions | ||
Internet Engineering Task Force (IETF) L. Ginsberg
Request for Comments: 7775 Cisco Systems
Updates: 5308 S. Litkowski
Category: Standards Track Orange Business Service
ISSN: 2070-1721 S. Previdi
Cisco Systems
February 2016
IS-IS Route Preference for Extended IP and IPv6 Reachability
Abstract
In existing specifications, the route preferences for IPv4/IPv6
Extended Reachability TLVs are not explicitly stated. There are also
inconsistencies in the definition of how the up/down bit applies to
route preference when the prefix advertisement appears in Level 2
Link State Protocol Data Units (LSPs). This document addresses these
issues.
This document updates RFC 5308.
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/rfc7775.
Ginsberg, et al. Standards Track [Page 1]
RFC 7775 IS-IS Route Preference February 2016
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Use of the Up/Down Bit in Level 2 LSPs . . . . . . . . . . . 3
3. Types of Routes in IS-IS Supported by Extended Reachability
TLVs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Types of Routes Supported by TLVs 135 and 235 . . . . . . 4
3.2. Types of Routes Supported by TLVs 236 and 237 . . . . . . 6
3.3. Order of Preference for All Types of Routes Supported by
TLVs 135 and 235 . . . . . . . . . . . . . . . . . . . . 7
3.4. Order of Preference for All Types of Routes Supported by
TLVs 236 and 237 . . . . . . . . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Normative References . . . . . . . . . . . . . . . . . . 8
5.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Example Interoperability Issue . . . . . . . . . . . 10
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
Ginsberg, et al. Standards Track [Page 2]
RFC 7775 IS-IS Route Preference February 2016
1. Introduction
[RFC5302] defines the route preference rules as they apply to TLVs
128 and 130. [RFC5305] introduced the IP Extended Reachability TLV
135 but did not explicitly adapt the route preference rules defined
in [RFC5302] for the new TLV. [RFC5308] defines the IPv6
Reachability TLV 236 and does include an explicit statement regarding
route preference -- but the statement introduces use of the up/down
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