Bidirectional Forwarding Detection (BFD) for EVPN Ethernet Segment Failover Use Case
draft-zwm-bess-es-failover-03
BESS WG Z. Zhang
Internet-Draft Y. Wang
Intended status: Standards Track G. Mirsky
Expires: May 19, 2021 ZTE Corporation
November 15, 2020
Bidirectional Forwarding Detection (BFD) for EVPN Ethernet Segment
Failover Use Case
draft-zwm-bess-es-failover-03
Abstract
This document introduces a method for fast switchover of Designated
Forwarder for Ethernet Segment failover by using Bidirectional
Forwarding Detection protocol.
Status of This Memo
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This Internet-Draft will expire on May 19, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 3
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. Proposal . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Specification . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. BDF changes . . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
[RFC7432] introduces Ethernet Virtual Private Network (EVPN)
technology. Designated Forwarder (DF) election procedures for multi-
homing Ethernet Segments has been described in it. When PE (provider
edge) receives BUM (Broadcast, Unknown Unicast and Multicast) flows,
only DF forwards the BUM flows to CE (customer edge). Non-DFs do not
forward the BUM flows in order to avoid duplication. If the link
between DF and CE fails, another PE will forward the BUM flows after
it is elected as DF.
[RFC8584] defines the DF election framework, including that Backup
Designated Forwarder (BDF) can be elected as the next best for the
role. But before the BDF is elected as DF, the BUM flows are
discarded after the link between DF and CE fails.
+-----+
+-----X----+ PE1 |
| +--+--+
|
+-+--+
| CE |
+-+--+
|
| +--+--+
+----------+ PE2 |
+-----+
For example, CE is multihomed to PE1 and PE2. PE1 is elected as DF.
All BUM flows are forwarded by PE1 when the link between PE1 and CE
is operational. When the link between PE1 and CE fails, the BUM
flows are discarded until PE2 is elected as DF.
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This document will use terminology defined in [RFC7432] and
[I-D.ietf-bess-evpn-lsp-ping].
2. Conventions used in this document
2.1. Terminology
BFD: Bidirectional Forwarding Detection
BDF: Backup Designted Forwarder
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