Hi BESS,
We have published version -00 of a draft that extends EVPN Assisted Replication
(AR) {{RFC9574}} to an SRv6 underlay:
Applicability of EVPN Assisted Replication to SRv6 Tunnels
https://datatracker.ietf.org/doc/html/draft-rabadan-bess-evpn-srv6-ar
This was briefly discussed at the BESS session in Vienna; this mail is to raise
wider awareness and invite people to review.
Background: RFC9574 optimizes ingress replication for EVPN BM traffic by
offloading replication from AR-LEAF nodes to AR-REPLICATORs. It is defined
around IP-tunnel semantics (IR-IP / AR-IP, VXLAN VNI) that do not map directly
to SRv6. RFC9252 supports EVPN BUM over SRv6 using ingress replication with
End.DT2M, but does not define AR roles or an AR-specific endpoint behavior.
What the draft does:
* Defines a new SRv6 endpoint behavior, End.DT2M.AR, for the AR-REPLICATOR
role (local L2 flooding plus re-replication to remote PEs).
* Uses a two-SID model: AR-REPLICATOR advertises an AR-SID (End.DT2M.AR) in
its Replicator-AR IMET route and a regular End.DT2M SID in its Regular-IR IMET
route — the SRv6 analog of AR-IP vs IR-IP.
*
Reuses RFC9574 control-plane procedures, with SRv6 SIDs carried in the BGP SRv6
L2 Service TLV.
*
Covers non-selective and selective AR, multihoming, and OISM / EVPN IGMP/MLD
proxy over SRv6.
Comments and feedback are welcome.
Thank you,
Jorge (on behalf of the authors)
Subject: New Version Notification for draft-rabadan-bess-evpn-srv6-ar-00.txt
A new version of Internet-Draft draft-rabadan-bess-evpn-srv6-ar-00.txt has
been successfully submitted by Jorge Rabadan and posted to the
IETF repository.
Name: draft-rabadan-bess-evpn-srv6-ar
Revision: 00
Title: Applicability of EVPN Assisted Replication to SRv6 Tunnels
Date: 2026-08-01
Group: Individual Submission
Pages: 18
URL: https://www.ietf.org/archive/id/draft-rabadan-bess-evpn-srv6-ar-00.txt
Status: https://datatracker.ietf.org/doc/draft-rabadan-bess-evpn-srv6-ar/
HTML:
https://www.ietf.org/archive/id/draft-rabadan-bess-evpn-srv6-ar-00.html
HTMLized: https://datatracker.ietf.org/doc/html/draft-rabadan-bess-evpn-srv6-ar
Abstract:
Assisted Replication (AR) is an optimized ingress replication
solution for Ethernet VPN (EVPN) Broadcast and Multicast (BM)
traffic. AR offloads the replication effort from ingress Network
Virtualization Edge (NVE) devices onto Assisted Replication
Replicators (AR-REPLICATORs). The base AR specification is focused
on Network Virtualization Overlay (NVO) networks that use IP tunnels,
and it is typically deployed for Virtual eXtensible Local Area
Network (VXLAN). EVPN services can also be instantiated over Segment
Routing over IPv6 (SRv6); however, the SRv6 EVPN transport
specification supports only ingress replication for BUM traffic, and
the AR procedures rely on IP-tunnel semantics (such as the tunnel
source and destination IP addresses) that do not map exactly to an
SRv6 data plane. As a result, AR cannot be readily deployed over
SRv6 tunnels.
This document specifies the applicability of Assisted Replication to
SRv6 tunnels, for EVPN BM traffic, for selective multicast based on
Internet Group Management Protocol (IGMP) and Multicast Listener
Discovery (MLD) proxy, and for EVPN IP multicast traffic based on
Optimized Inter-Subnet Multicast (OISM). It defines a new SRv6
Endpoint behavior for the AR-REPLICATOR role and the associated
control-plane procedures, so that the AR solution can be used with an
SRv6 underlay.
The IETF Secretariat
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