Network Working Group A. Lindem, Ed.
Request for Comments: 4970 Redback Networks
Category: Standards Track N. Shen
JP. Vasseur
Cisco Systems
R. Aggarwal
Juniper Networks
S. Shaffer
BridgePort Networks
July 2007
Extensions to OSPF for Advertising Optional Router Capabilities
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
It is useful for routers in an OSPFv2 or OSPFv3 routing domain to
know the capabilities of their neighbors and other routers in the
routing domain. This document proposes extensions to OSPFv2 and
OSPFv3 for advertising optional router capabilities. A new Router
Information (RI) Link State Advertisement (LSA) is proposed for this
purpose. In OSPFv2, the RI LSA will be implemented with a new opaque
LSA type ID. In OSPFv3, the RI LSA will be implemented with a new
LSA type function code. In both protocols, the RI LSA can be
advertised at any of the defined flooding scopes (link, area, or
autonomous system (AS)).
Lindem, et al. Standards Track [Page 1]
RFC 4970 OSPF Capability Extensions July 2007
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Notation . . . . . . . . . . . . . . . . . . 3
2. OSPF Router Information (RI) LSA . . . . . . . . . . . . . . . 3
2.1. OSPFv2 Router Information (RI) Opaque LSA . . . . . . . . 3
2.2. OSPFv3 Router Information (RI) Opaque LSA . . . . . . . . 5
2.3. OSPF Router Informational Capabilities TLV . . . . . . . . 5
2.4. Assigned OSPF Router Informational Capability Bits . . . . 6
2.5. Flooding Scope of the Router Information LSA . . . . . . . 7
3. Router Information LSA Opaque Usage and Applicability . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Normative References . . . . . . . . . . . . . . . . . . . 10
6.2. Informative References . . . . . . . . . . . . . . . . . . 10
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 11
Lindem, et al. Standards Track [Page 2]
RFC 4970 OSPF Capability Extensions July 2007
1. Introduction
It is useful for routers in an OSPFv2 [OSPF] or OSPFv3 [OSPFV3]
routing domain to know the capabilities of their neighbors and other
routers in the routing domain. This can be useful for both the
advertisement and discovery of OSPFv2 and OSPFv3 capabilities.
Throughout this document, OSPF will be used when the specification is
applicable to both OSPFv2 and OSPFv3. Similarly, OSPFv2 or OSPFv3
will be used when the text is protocol specific.
OSPF uses the options field in LSAs and hello packets to advertise
optional router capabilities. In the case of OSPFv2, all the bits in
this field have been allocated so new optional capabilities cannot be
advertised. This document proposes extensions to OSPF to advertise
these optional capabilities via opaque LSAs in OSPFv2 and new LSAs in
OSPFv3. For existing OSPF capabilities, backward- compatibility
issues dictate that this advertisement is used primarily for
informational purposes. For future OSPF features, this advertisement
MAY be used as the sole mechanism for advertisement and discovery.
1.1. Requirements Notation
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 [RFC-KEYWORDS].
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