Unaffiliated BFD Echo Function
draft-ietf-bfd-unaffiliated-echo-00
BFD Working Group W. Cheng
Internet-Draft R. Wang
Updates: 5880 (if approved) China Mobile
Intended status: Standards Track X. Min
Expires: March 13, 2021 A. Liu
ZTE Corp.
R. Rahman
Cisco Systems
R. Boddireddy
Juniper Networks
September 9, 2020
Unaffiliated BFD Echo Function
draft-ietf-bfd-unaffiliated-echo-00
Abstract
Bidirectional Forwarding Detection (BFD) is a fault detection
protocol that can quickly determine a communication failure between
two forwarding engines. This document proposes a use of BFD echo
where the local system supports BFD but the neighboring system does
not support BFD.
Status of This Memo
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This Internet-Draft will expire on March 13, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Unaffiliated BFD Echo Behavior . . . . . . . . . . . . . . . 3
3. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
To minimize the impact of device faults on services and improve
network availability, a network device must be able to quickly detect
faults in communication with adjacent devices. Measures can then be
taken to promptly rectify the faults to ensure service continuity.
BFD [RFC5880] is a low-overhead, short-duration method to detect
faults on the path between adjacent forwarding engines. The faults
can be interface, data link, and even forwarding engine faults. It
is a single, unified mechanism to monitor any media and protocol
layers in real time.
BFD defines asynchronous mode to satisfy various deployment
scenarios, also supports echo function to reduce the device
requirement for BFD. When the echo function is activated, the local
system sends a BFD echo packet and the remote system loops back the
packet through the forwarding path. If several consecutive echo
packets are not received, the session is declared to be Down.
When using BFD echo function, it is not clear whether the devices
using echo function need to support the full BFD procotol, including
maintaining the state machine of BFD session as described in
[RFC5880] and [RFC5881]. According to different understanding, there
are two typical scenarios as below:
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