OSPF Extensions to Advertise Seamless Bidirectional Forwarding Detection (S-BFD) Target Discriminators
RFC 7884
Internet Engineering Task Force (IETF) C. Pignataro
Request for Comments: 7884 Cisco
Category: Standards Track M. Bhatia
ISSN: 2070-1721 Ionos Networks
S. Aldrin
Huawei Technologies
T. Ranganath
Nokia
July 2016
OSPF Extensions to Advertise Seamless Bidirectional Forwarding Detection
(S-BFD) Target Discriminators
Abstract
This document defines a new OSPF Router Information (RI) TLV that
allows OSPF routers to flood the Seamless Bidirectional Forwarding
Detection (S-BFD) Discriminator values associated with a target
network identifier. This mechanism is applicable to both OSPFv2 and
OSPFv3.
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 7841.
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/rfc7884.
Pignataro, et al. Standards Track [Page 1]
RFC 7884 S-BFD Discriminators in OSPF July 2016
Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction ....................................................3
1.1. Relationship between OSPF and S-BFD ........................3
2. Implementation ..................................................3
2.1. S-BFD Discriminator TLV ....................................4
2.2. Flooding Scope .............................................4
3. Backward Compatibility ..........................................5
4. Security Considerations .........................................5
5. IANA Considerations .............................................6
6. References ......................................................6
6.1. Normative References .......................................6
6.2. Informative References .....................................6
Acknowledgements ...................................................7
Authors' Addresses .................................................7
Pignataro, et al. Standards Track [Page 2]
RFC 7884 S-BFD Discriminators in OSPF July 2016
1. Introduction
Seamless Bidirectional Forwarding Detection (S-BFD), specified in
[RFC7880], is a simplified mechanism for using BFD with many
negotiations eliminated. This is achieved by using 4-octet
discriminators, unique within an administrative domain, to identify
the network targets. These S-BFD Discriminators can be advertised by
the IGPs, and this document concerns itself with OSPF. Specifically,
this document defines a new TLV (named the S-BFD Discriminator TLV)
to be carried within the OSPF Router Information (RI) Link State
Advertisement (LSA) [RFC7770].
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 2119 [RFC2119].
1.1. Relationship between OSPF and S-BFD
This document implicitly defines a relationship between OSPF and
S-BFD. S-BFD assigns one or more discriminators to each S-BFD
reflector node. OSPF, in turn, learns about these from S-BFD and
floods them in the newly defined TLV. After this information is
flooded, it is stored in all the OSPF nodes such that S-BFD
initiators can map out target nodes to target discriminators and can
therefore construct the S-BFD probe.
When multiple S-BFD Discriminators are advertised, how a given
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