Bidirectional Forwarding Detection (BFD) for Multi-point Networks and Protocol Independent Multicast - Sparse Mode (PIM-SM) Use Case
draft-ietf-pim-bfd-p2mp-use-case-02
PIM Working Group G. Mirsky
Internet-Draft ZTE Corp.
Intended status: Standards Track J. Xiaoli
Expires: January 26, 2020 ZTE Corporation
July 25, 2019
Bidirectional Forwarding Detection (BFD) for Multi-point Networks and
Protocol Independent Multicast - Sparse Mode (PIM-SM) Use Case
draft-ietf-pim-bfd-p2mp-use-case-02
Abstract
This document discusses the use of Bidirectional Forwarding Detection
(BFD) for multi-point networks to provide nodes that participate in
Protocol Independent Multicast - Sparse Mode (PIM-SM) with the sub-
second convergence. Optional extension to PIM-SM Hello, as specified
in RFC 7761, to bootstrap point-to-multipoint BFD session. also
defined in this document.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions used in this document . . . . . . . . . . . . 3
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 3
1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3. Applicability of p2mp BFD . . . . . . . . . . . . . . . . . . 3
3.1. Multipoint BFD Encapsulation . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
7. Normative References . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Faster convergence in the control plane, in general, is beneficial
and allows minimizing periods of traffic blackholing, transient
routing loops, and other scenarios that may negatively affect service
data flow. That equally applies to unicast and multicast routing
protocols.
[RFC7761] is the current specification of the Protocol Independent
Multicast - Sparse Mode (PIM-SM) for IPv4 and IPv6 networks.
Confirming implementation of PIM-SM elects a Designated Router (DR)
on each PIM-SM interface. When a group of PIM-SM nodes is connected
to shared-media segment, e.g., Ethernet, the one elected as DR is to
act on behalf of directly connected hosts in the context of the PIM-
SM protocol. Failure of the DR impacts the quality of the multicast
services it provides to directly connected hosts because the default
failure detection interval for PIM-SM routers is 105 seconds.
Introduction of Backup DR (BDR), proposed in
[I-D.ietf-pim-dr-improvement], improves convergence time in the PIM-
SM over shared-media segment but still depends on long failure
detection interval.
Bidirectional Forwarding Detection (BFD) [RFC5880] had been
originally defined to detect failure of point-to-point (p2p) paths -
single-hop [RFC5881], multihop [RFC5883]. [RFC8562] extends the BFD
base specification [RFC5880] for multipoint and multicast networks,
which precisely characterizes deployment scenarios for PIM-SM over
LAN segment. This document demonstrates how point-to-multipoint
(p2mp) BFD can enable faster detection of PIM-SM router failure and
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