EVPN Optimized Inter-Subnet Multicast (OISM) Forwarding
draft-ietf-bess-evpn-irb-mcast-05
BESS W. Lin
Internet-Draft Z. Zhang
Intended status: Standards Track J. Drake
Expires: April 16, 2021 E. Rosen, Ed.
Juniper Networks, Inc.
J. Rabadan
Nokia
A. Sajassi
Cisco Systems
October 13, 2020
EVPN Optimized Inter-Subnet Multicast (OISM) Forwarding
draft-ietf-bess-evpn-irb-mcast-05
Abstract
Ethernet VPN (EVPN) provides a service that allows a single Local
Area Network (LAN), comprising a single IP subnet, to be divided into
multiple "segments". Each segment may be located at a different
site, and the segments are interconnected by an IP or MPLS backbone.
Intra-subnet traffic (either unicast or multicast) always appears to
the endusers to be bridged, even when it is actually carried over the
IP or MPLS backbone. When a single "tenant" owns multiple such LANs,
EVPN also allows IP unicast traffic to be routed between those LANs.
This document specifies new procedures that allow inter-subnet IP
multicast traffic to be routed among the LANs of a given tenant,
while still making intra-subnet IP multicast traffic appear to be
bridged. These procedures can provide optimal routing of the inter-
subnet multicast traffic, and do not require any such traffic to
leave a given router and then reenter that same router. These
procedures also accommodate IP multicast traffic that needs to travel
to or from systems that are outside the EVPN domain.
Status of This Memo
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Lin, et al. Expires April 16, 2021 [Page 1]
Internet-Draft evpn-irb-mcast October 2020
This Internet-Draft will expire on April 16, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Background . . . . . . . . . . . . . . . . . . . . . . . 4
1.1.1. Segments, Broadcast Domains, and Tenants . . . . . . 4
1.1.2. Inter-BD (Inter-Subnet) IP Traffic . . . . . . . . . 5
1.1.3. EVPN and IP Multicast . . . . . . . . . . . . . . . . 6
1.1.4. BDs, MAC-VRFS, and EVPN Service Models . . . . . . . 7
1.2. Need for EVPN-aware Multicast Procedures . . . . . . . . 7
1.3. Additional Requirements That Must be Met by the Solution 8
1.4. Terminology . . . . . . . . . . . . . . . . . . . . . . . 10
1.5. Model of Operation: Overview . . . . . . . . . . . . . . 12
1.5.1. Control Plane . . . . . . . . . . . . . . . . . . . . 12
1.5.2. Data Plane . . . . . . . . . . . . . . . . . . . . . 14
2. Detailed Model of Operation . . . . . . . . . . . . . . . . . 17
2.1. Supplementary Broadcast Domain . . . . . . . . . . . . . 17
2.2. Detecting When a Route is About/For/From a Particular BD 18
2.3. Use of IRB Interfaces at Ingress PE . . . . . . . . . . . 21
2.4. Use of IRB Interfaces at an Egress PE . . . . . . . . . . 23
2.5. Announcing Interest in (S,G) . . . . . . . . . . . . . . 23
2.6. Tunneling Frames from Ingress PE to Egress PEs . . . . . 24
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