Seamless Bidirectional Forwarding Detection (S-BFD) Use Cases
RFC 7882
Internet Engineering Task Force (IETF) S. Aldrin
Request for Comments: 7882 Google, Inc.
Category: Informational C. Pignataro
ISSN: 2070-1721 Cisco
G. Mirsky
Ericsson
N. Kumar
Cisco
July 2016
Seamless Bidirectional Forwarding Detection (S-BFD) Use Cases
Abstract
This document describes various use cases for Seamless Bidirectional
Forwarding Detection (S-BFD) and provides requirements such that
protocol mechanisms allow for simplified detection of forwarding
failures.
These use cases support S-BFD, which is a simplified mechanism for
using BFD with a large proportion of negotiation aspects eliminated,
accelerating the establishment of a BFD session. The benefits of
S-BFD include quick provisioning, as well as improved control and
flexibility for network nodes initiating path monitoring.
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 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/rfc7882.
Aldrin, et al. Informational [Page 1]
RFC 7882 S-BFD Use Cases July 2016
Copyright Notice
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Table of Contents
1. Introduction ....................................................3
1.1. Terminology ................................................3
2. Introduction to Seamless BFD ....................................4
3. Use Cases .......................................................5
3.1. Unidirectional Forwarding Path Validation ..................5
3.2. Validation of the Forwarding Path prior to
Switching Traffic ..........................................6
3.3. Centralized Traffic Engineering ............................7
3.4. BFD in Centralized Segment Routing .........................8
3.5. Efficient BFD Operation under Resource Constraints .........8
3.6. BFD for Anycast Addresses ..................................8
3.7. BFD Fault Isolation ........................................9
3.8. Multiple BFD Sessions to the Same Target Node ..............9
3.9. An MPLS BFD Session per ECMP Path .........................10
4. Detailed Requirements for Seamless BFD .........................11
5. Security Considerations ........................................12
6. References .....................................................12
6.1. Normative References ......................................12
6.2. Informative References ....................................13
Acknowledgements ..................................................15
Contributors ......................................................15
Authors' Addresses ................................................15
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RFC 7882 S-BFD Use Cases July 2016
1. Introduction
Bidirectional Forwarding Detection (BFD), as defined in [RFC5880], is
a lightweight protocol used to detect forwarding failures. Various
protocols, applications, and clients rely on BFD for failure
detection. Even though the protocol is lightweight and simple, there
are certain use cases where faster setup of sessions and faster
continuity checks of the data-forwarding paths are necessary. This
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