Advertising Seamless Bidirectional Forwarding Detection (S-BFD) Discriminators in the Layer Two Tunneling Protocol Version 3 (L2TPv3)
RFC 7886
Internet Engineering Task Force (IETF) V. Govindan
Request for Comments: 7886 C. Pignataro
Category: Standards Track Cisco
ISSN: 2070-1721 July 2016
Advertising Seamless Bidirectional Forwarding Detection (S-BFD)
Discriminators in the Layer Two Tunneling Protocol Version 3 (L2TPv3)
Abstract
This document defines a new Attribute-Value Pair (AVP) that allows
L2TP Control Connection Endpoints (LCCEs) to advertise one or more
Seamless Bidirectional Forwarding Detection (S-BFD) Discriminator
values using the Layer Two Tunneling Protocol version 3 (L2TPv3).
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/rfc7886.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Govindan & Pignataro Standards Track [Page 1]
RFC 7886 S-BFD Discriminators in L2TPv3 July 2016
Table of Contents
1. Introduction ....................................................2
1.1. Terminology ................................................2
2. S-BFD Target Discriminator ID AVP ...............................2
2.1. Encoding Format ............................................3
3. IANA Considerations .............................................4
4. Security Considerations .........................................4
5. References ......................................................5
5.1. Normative References .......................................5
5.2. Informative References .....................................5
Acknowledgements ...................................................6
Contributors .......................................................6
Authors' Addresses .................................................6
1. Introduction
[RFC7880] defines a simplified mechanism to use Bidirectional
Forwarding Detection (BFD) [RFC5880], referred to as Seamless
Bidirectional Forwarding Detection (S-BFD). The S-BFD mechanism
depends on network nodes knowing the BFD Discriminators that each
node in the network has reserved for this purpose. S-BFD requires
the usage of unique discriminators within an administrative domain.
The use of the Layer Two Tunneling Protocol version 3 (L2TPv3)
[RFC3931] is one possible means of advertising these discriminators.
This document specifies the encoding to be used when S-BFD
Discriminators are advertised using L2TPv3.
1.1. Terminology
The reader is expected to be very familiar with the terminology and
protocol constructs defined in S-BFD (see Section 2 of [RFC7880]) and
L2TPv3 (see Section 1.3 of [RFC3931]).
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].
2. S-BFD Target Discriminator ID AVP
The S-BFD Target Discriminator Identifier (ID) Attribute Value Pair
(AVP) is exchanged using the ICRQ (Incoming-Call-Request), ICRP
(Incoming-Call-Reply), OCRQ (Outgoing-Call-Request), and OCRP
(Outgoing-Call-Reply) control messages during session negotiation.
Govindan & Pignataro Standards Track [Page 2]
RFC 7886 S-BFD Discriminators in L2TPv3 July 2016
2.1. Encoding Format
The S-BFD Target Discriminator ID AVP, Attribute Type 102, is an
identifier used to advertise the S-BFD target discriminator(s)
supported by an L2TP Control Connection Endpoint (LCCE) for the S-BFD
reflector operation. This AVP indicates that the advertiser
implements an S-BFD reflector supporting the specified target
discriminator(s) and is ready for S-BFD reflector operation. The
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