OSPF Stub Router Advertisement
RFC 6987
| Document | Type |
RFC - Informational
(September 2013; Errata)
Obsoletes RFC 3137
|
|
|---|---|---|---|
| Last updated | 2018-12-20 | ||
| Replaces | draft-retana-ospf-rfc3137bis | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | WG Document | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 6987 (Informational) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Stewart Bryant | ||
| IESG note | Abhay Roy (akr@cisco.com) is the document shepherd. | ||
| Send notices to | (None) | ||
| IANA | IANA review state | IANA - Review Needed | |
| IANA action state | No IANA Actions | ||
Internet Engineering Task Force (IETF) A. Retana
Request for Comments: 6987 L. Nguyen
Obsoletes: 3137 Cisco Systems, Inc.
Category: Informational A. Zinin
ISSN: 2070-1721 Cinarra Systems
R. White
D. McPherson
Verisign, Inc.
September 2013
OSPF Stub Router Advertisement
Abstract
This document describes a backward-compatible technique that may be
used by OSPF (Open Shortest Path First) implementations to advertise
a router's unavailability to forward transit traffic or to lower the
preference level for the paths through such a router.
This document obsoletes RFC 3137.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see 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/rfc6987.
Retana, et al. Informational [Page 1]
RFC 6987 OSPF Stub Router Advertisement September 2013
Copyright Notice
Copyright (c) 2013 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. OSPFv3-Only Solution . . . . . . . . . . . . . . . . . . 3
3. Maximum Link Metric . . . . . . . . . . . . . . . . . . . . . 4
4. Deployment Considerations . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Appendix A. Changes from RFC 3137 . . . . . . . . . . . . . . . 6
1. Introduction
In some situations, it may be advantageous to inform routers in a
network not to use a specific router as a transit point but to still
route to it. Possible situations include the following:
o The router is in a critical condition (for example, has a very
high CPU load or does not have enough memory to store all Link
State Advertisements (LSAs) or build the routing table).
o Graceful introduction and removal of the router to/from the
network.
o Other (administrative or traffic engineering) reasons.
Retana, et al. Informational [Page 2]
RFC 6987 OSPF Stub Router Advertisement September 2013
Note that the solution introduced in this document does not remove
the router from the topology view of the network (as could be done by
just flushing that router's router-LSA) but discourages other routers
from using it for transit routing, while still routing packets to the
router's own IP addresses, i.e., the router is announced as a stub.
It must be emphasized that the solution provides real benefits in
networks designed with at least some level of redundancy, so that
traffic can be routed around the stub router. Otherwise, traffic
destined for the networks and reachable through such a stub router
may still be routed through it.
2. Solutions
The solution introduced in this document solves two challenges
associated with the outlined problem. In the description below,
router X is the router announcing itself as a stub. The challenges
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