Seamless Bidirectional Forwarding Detection (S-BFD) for IPv4, IPv6, and MPLS
RFC 7881
Internet Engineering Task Force (IETF) C. Pignataro
Request for Comments: 7881 D. Ward
Category: Standards Track Cisco
ISSN: 2070-1721 N. Akiya
Big Switch Networks
July 2016
Seamless Bidirectional Forwarding Detection (S-BFD)
for IPv4, IPv6, and MPLS
Abstract
This document defines procedures for using Seamless Bidirectional
Forwarding Detection (S-BFD) in IPv4, IPv6, and MPLS environments.
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/rfc7881.
Copyright Notice
Copyright (c) 2016 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
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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.
Pignataro, et al. Standards Track [Page 1]
RFC 7881 Seamless BFD for IPv4, IPv6, and MPLS July 2016
Table of Contents
1. Introduction ....................................................2
2. S-BFD UDP Port ..................................................2
3. S-BFD Echo UDP Port .............................................3
4. S-BFD Control Packet Demultiplexing .............................3
5. Initiator Procedures ............................................3
5.1. Details of S-BFD Control Packets Sent by SBFDInitiator .....4
5.1.1. Target versus Remote Entity (S-BFD Discriminator) ...4
6. Responder Procedures ............................................5
6.1. Details of S-BFD Control Packets Sent by SBFDReflector .....5
7. Security Considerations .........................................6
8. IANA Considerations .............................................6
9. References ......................................................7
9.1. Normative References .......................................7
9.2. Informative References .....................................7
Acknowledgements ...................................................8
Contributors .......................................................8
Authors' Addresses .................................................8
1. Introduction
Seamless Bidirectional Forwarding Detection (S-BFD) [RFC7880] defines
a generalized mechanism to allow network nodes to seamlessly perform
continuity checks to remote entities. This document defines
necessary procedures for using S-BFD in IPv4, IPv6, and MPLS
environments.
The reader is expected to be familiar with the IP [RFC791] [RFC2460],
BFD [RFC5880], MPLS BFD [RFC5884], and S-BFD [RFC7880] terms and
protocol constructs.
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 UDP Port
A new UDP port is defined for use by S-BFD in IPv4, IPv6, and MPLS
environments: 7784.
In S-BFD Control packets from the SBFDInitiator to the SBFDReflector,
the SBFDReflector session MUST listen for incoming S-BFD Control
packets on port 7784. SBFDInitiator sessions MUST transmit S-BFD
Control packets with destination port 7784. The source port of the
S-BFD Control packets transmitted by SBFDInitiator sessions can be
any port, with one exception: it MUST NOT be 7784. The same UDP
Pignataro, et al. Standards Track [Page 2]
RFC 7881 Seamless BFD for IPv4, IPv6, and MPLS July 2016
source port number MUST be used for all S-BFD Control packets
associated with a particular SBFDInitiator session. The source port
number is unique among all SBFDInitiator sessions on the system.
In S-BFD Control packets from the SBFDReflector to the SBFDInitiator,
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