rfc9572.original   rfc9572.txt 
BESS Z. Zhang Internet Engineering Task Force (IETF) Z. Zhang
Internet-Draft W. Lin Request for Comments: 9572 W. Lin
Updates: 7432 (if approved) Juniper Networks Updates: 7432 Juniper Networks
Intended status: Standards Track J. Rabadan Category: Standards Track J. Rabadan
Expires: May 22, 2022 Nokia ISSN: 2070-1721 Nokia
K. Patel K. Patel
Arrcus Arrcus
A. Sajassi A. Sajassi
Cisco Systems Cisco Systems
November 18, 2021 May 2024
Updates on EVPN BUM Procedures Updates to EVPN Broadcast, Unknown Unicast, or Multicast (BUM)
draft-ietf-bess-evpn-bum-procedure-updates-14 Procedures
Abstract Abstract
This document specifies updated procedures for handling broadcast, This document specifies updated procedures for handling Broadcast,
unknown unicast, and multicast (BUM) traffic in Ethernet VPNs (EVPN), Unknown Unicast, or Multicast (BUM) traffic in Ethernet VPNs (EVPNs),
including selective multicast, and provider tunnel segmentation. including selective multicast and segmentation of provider tunnels.
This document updates RFC 7432. This document updates RFC 7432.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on May 22, 2022. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9572.
Copyright Notice Copyright Notice
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document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language
2.1. Tunnel Segmentation . . . . . . . . . . . . . . . . . . . 4 1.2. Terminology
2.1.1. Reasons for Tunnel Segmentation . . . . . . . . . . . 5 2. Tunnel Segmentation
3. Additional Route Types of EVPN NLRI . . . . . . . . . . . . . 6 2.1. Reasons for Tunnel Segmentation
3.1. Per-Region I-PMSI A-D route . . . . . . . . . . . . . . . 7 3. Additional Route Types of EVPN NLRI
3.2. S-PMSI A-D route . . . . . . . . . . . . . . . . . . . . 7 3.1. Per-Region I-PMSI A-D Route
3.3. Leaf A-D route . . . . . . . . . . . . . . . . . . . . . 8 3.2. S-PMSI A-D Route
4. Selective Multicast . . . . . . . . . . . . . . . . . . . . . 8 3.3. Leaf A-D Route
5. Inter-AS Segmentation . . . . . . . . . . . . . . . . . . . . 9 4. Selective Multicast
5.1. Differences from Section 7.2.2 of [RFC7117] When Applied 5. Inter-AS Segmentation
to EVPN . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1. Differences from Section 7.2.2 of RFC 7117 when Applied to
5.2. I-PMSI Leaf Tracking . . . . . . . . . . . . . . . . . . 11 EVPNs
5.3. Backward Compatibility . . . . . . . . . . . . . . . . . 11 5.2. I-PMSI Leaf Tracking
5.3.1. Designated ASBR Election . . . . . . . . . . . . . . 13 5.3. Backward Compatibility
6. Inter-Region Segmentation . . . . . . . . . . . . . . . . . . 13 5.3.1. Designated ASBR Election
6.1. Area/AS vs. Region . . . . . . . . . . . . . . . . . . . 13 6. Inter-Region Segmentation
6.2. Per-region Aggregation . . . . . . . . . . . . . . . . . 14 6.1. Area/AS vs. Region
6.3. Use of S-NH-EC . . . . . . . . . . . . . . . . . . . . . 15 6.2. Per-Region Aggregation
6.4. Ingress PE's I-PMSI Leaf Tracking . . . . . . . . . . . . 16 6.3. Use of S-NH-EC
7. Multi-homing Support . . . . . . . . . . . . . . . . . . . . 16 6.4. Ingress PE's I-PMSI Leaf Tracking
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 7. Multihoming Support
9. Security Considerations . . . . . . . . . . . . . . . . . . . 17 8. IANA Considerations
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17 9. Security Considerations
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 17 10. References
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.1. Normative References
12.1. Normative References . . . . . . . . . . . . . . . . . . 18 10.2. Informative References
12.2. Informative References . . . . . . . . . . . . . . . . . 19 Acknowledgements
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Contributors
Authors' Addresses
1. Terminology 1. Introduction
It is expected that audience is familiar with MVPN [RFC6513] [RFC7117] specifies procedures for multicast in the Virtual Private
[RFC6514], VPLS Multicast [RFC7117] and EVPN [RFC7432] concepts and LAN Service (VPLS multicast), using both inclusive tunnels and
terminologies. For convenience, the following terms are briefly selective tunnels with or without inter-AS segmentation, similar to
explained. the Multicast VPN (MVPN) procedures specified in [RFC6513] and
[RFC6514]. [RFC7524] specifies inter-area tunnel segmentation
procedures for both VPLS multicast and MVPNs.
o PMSI [RFC6513]: P-Multicast Service Interface - a conceptual [RFC7432] specifies BGP MPLS-based Ethernet VPN (EVPN) procedures,
including those handling Broadcast, Unknown Unicast, or Multicast
(BUM) traffic. [RFC7432] refers to [RFC7117] for details but leaves
a few feature gaps related to selective tunnel and tunnel
segmentation (Section 2.1).
This document aims to fill in those gaps by covering the use of
selective and segmented tunnels in EVPNs. In the same way that
[RFC7432] refers to [RFC7117] for details, this document only
specifies differences from relevant procedures provided in [RFC7117]
and [RFC7524], rather than repeating the text from those documents.
Note that these differences are applicable to EVPNs only and are not
updates to [RFC7117] or [RFC7524].
MVPN, VPLS, and EVPN technologies all need to discover other Provider
Edges (PEs) in the same L3/L2 VPN and announce the inclusive tunnels.
MVPN technology introduced the Inclusive P-Multicast Service
Interface (I-PMSI) concept and uses I-PMSI Auto-Discovery (A-D)
routes for that purpose. EVPN technology uses Inclusive Multicast
Ethernet Tag (IMET) A-D routes, but VPLS technology just adds a PMSI
Tunnel Attribute (PTA) to an existing VPLS A-D route for that
purpose. For selective tunnels, they all do use the same term:
Selective PMSI (S-PMSI) A-D routes.
This document often refers to the I-PMSI concept, which is the same
for all three technologies. For consistency and convenience, an
EVPN's IMET A-D route and a VPLS's VPLS A-D route carrying a PTA for
BUM traffic purposes may each be referred to as an I-PMSI A-D route,
depending on the context.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Terminology
It is assumed that the reader is familiar with concepts and
terminologies related to MVPN technology [RFC6513] [RFC6514], VPLS
multicast [RFC7117], and EVPN technology [RFC7432]. For convenience,
the following terms are briefly explained.
AS: Autonomous System
PMSI [RFC6513]: P-Multicast Service Interface. A conceptual
interface for a PE to send customer multicast traffic to all or interface for a PE to send customer multicast traffic to all or
some PEs in the same VPN. some PEs in the same VPN.
o I-PMSI: Inclusive PMSI - to all PEs in the same VPN. I-PMSI: Inclusive PMSI. Enables traffic to be sent to all PEs in
the same VPN.
o S-PMSI: Selective PMSI - to some of the PEs in the same VPN. S-PMSI: Selective PMSI. Enables traffic to be sent to some of the
PEs in the same VPN.
o I/S-PMSI A-D Route: Auto-Discovery routes used to announce the I/S-PMSI A-D Route: Auto-Discovery route used to announce the
tunnels that instantiate an I/S-PMSI. tunnels that instantiate an I/S-PMSI.
o Leaf Auto-Discovery (A-D) routes [RFC6513]: For explicit leaf Leaf Auto-Discovery (A-D) Route [RFC6513]: For explicit leaf-
tracking purpose. Triggered by I/S-PMSI A-D routes and targeted tracking purposes. Triggered by I/S-PMSI A-D routes and targeted
at triggering route's (re-)advertiser. Its NLRI embeds the entire at the triggering route's (re-)advertiser. Its Network Layer
NLRI of the triggering PMSI A-D route. Reachability Information (NLRI) embeds the entire NLRI of the
triggering PMSI A-D route.
o IMET A-D route [RFC7432]: Inclusive Multicast Ethernet Tag A-D IMET A-D Route [RFC7432]: Inclusive Multicast Ethernet Tag A-D
route. The EVPN equivalent of MVPN Intra-AS I-PMSI A-D route used route. The EVPN equivalent of an MVPN Intra-AS I-PMSI A-D route
to announce the tunnels that instantiate an I-PMSI. used to announce the tunnels that instantiate an I-PMSI.
o SMET A-D route [I-D.ietf-bess-evpn-igmp-mld-proxy]: Selective SMET A-D Route [RFC9251]: Selective Multicast Ethernet Tag A-D
Multicast Ethernet Tag A-D route. The EVPN equivalent of MVPN route. The EVPN equivalent of an MVPN Leaf A-D route, but
Leaf A-D route but unsolicited and untargeted. unsolicited and untargeted.
o PMSI Tunnel Attribute (PTA): An optional transitive BGP attribute PMSI Tunnel Attribute (PTA): An optional transitive BGP attribute
that may be attached to PMSI/Leaf A-D routes to provide that may be attached to PMSI/Leaf A-D routes to provide
information for a PMSI tunnel. information for a PMSI tunnel.
2. Introduction IBGP: Internal BGP (BGP connection between internal peers).
[RFC7117] specifies procedures for Multicast in Virtual Private LAN
Service (VPLS Multicast) using both inclusive tunnels and selective
tunnels with or without inter-as segmentation, similar to the
Multicast VPN (MVPN) procedures specified in [RFC6513] and [RFC6514].
[RFC7524] specifies inter-area tunnel segmentation procedures for
both VPLS Multicast and MVPN.
[RFC7432] specifies BGP MPLS-Based Ethernet VPN (EVPN) procedures,
including those handling broadcast, unknown unicast, and multicast
(BUM) traffic. A lot of details are referred to [RFC7117], yet with
quite some feature gaps like selective tunnel and tunnel segmentation
(Section 2.1).
This document aims at filling the gaps - cover the use of selective
and segmented tunnels in EVPN. It follows the same editorial choice
as in RFC7432 and only specifies differences from relevant procedures
in [RFC7117] and [RFC7524], instead of repeating the text. Note that
these differences are applicable to EVPN only, and are not updates to
[RFC7117] or [RFC7524].
MVPN, VPLS and EVPN all have the need to discover other PEs in the EBGP: External BGP (BGP connection between external peers).
same L3/L2 VPN and announce the inclusive tunnels. MVPN introduced
the I-PMSI concept and uses I-PMSI A-D route for that. EVPN uses
Inclusive Multicast Ethernet Tag Route (IMET) A-D route but VPLS just
adds an PMSI Tunnel Attribute (PTA) to the existing VPLS A-D route
for that purpose. For selective tunnels, they all do use the same
term S-PMSI A-D routes.
Many places of this document involve the I-PMSI concept that is all RT: Route Target. Controls route importation and propagation.
the same for all three technologies. For consistency and
convenience, EVPN's IMET and VPLS's VPLS A-D route carrying PTA for
BUM traffic purpose may all be referred to as I-PMSI A-D routes
depending on the context.
2.1. Tunnel Segmentation 2. Tunnel Segmentation
MVPN provider tunnels and EVPN/VPLS BUM provider tunnels, which are MVPN provider tunnels and EVPN/VPLS BUM provider tunnels, which are
referred to as MVPN/EVPN/VPLS provider tunnels in this document for referred to as MVPN/EVPN/VPLS provider tunnels in this document for
simplicity, can be segmented for technical or administrative reasons, simplicity, can be segmented for technical or administrative reasons,
which are summarized in Section 2.1.1 of this document. [RFC6513] which are summarized in Section 2.1 of this document. [RFC6513] and
and [RFC6514] cover MVPN inter-as segmentation, [RFC7117] covers VPLS [RFC6514] cover MVPN inter-AS segmentation, [RFC7117] covers VPLS
multicast inter-as segmentation, and [RFC7524] (Seamless MPLS multicast inter-AS segmentation, and [RFC7524] (seamless MPLS
Multicast) covers inter-area segmentation for both MVPN and VPLS. multicast) covers inter-area segmentation for both MVPNs and VPLSs.
With tunnel segmentation, different segments of an end-to-end tunnel With tunnel segmentation, different segments of an end-to-end tunnel
may have different encapsulation overhead. However, the largest may have different encapsulation overheads. However, the largest
overhead of the tunnel caused by an encapsulation method on a overhead of the tunnel caused by an encapsulation method on a
particular segment is not different from the case of a non-segmented particular segment is not different from the case of a non-segmented
tunnel with that encapsulation method. This is similar to the case tunnel with that encapsulation method. This is similar to the case
of a network with different link types. of a network with different link types.
There is a difference between MVPN and VPLS multicast inter-as There is a difference between MVPN and VPLS multicast inter-AS
segmentation (the VPLS approach is briefly discribed in Section 5.1). segmentation (the VPLS approach is briefly described in Section 5.1).
For simplicity, EVPN will use the same procedures as in MVPN. All For simplicity, EVPNs will use the same procedures as those for
ASBRs can re-advertise their choice of the best route. Each can MVPNs. All ASBRs can re-advertise their choice of the best route.
become the root of its intra-AS segment and inject traffic it Each can become the root of its intra-AS segment and inject traffic
receives from its upstream, while each downstream PE/ASBR will only it receives from its upstream, while each downstream PE/ASBR will
pick one of the upstream ASBRs as its upstream. This is also the only pick one of the upstream ASBRs as its upstream. This is also
behavior even for VPLS in case of inter-area segmentation. the behavior even for VPLS in the case of inter-area segmentation.
For inter-area segmentation, [RFC7524] requires the use of Inter-area For inter-area segmentation, [RFC7524] requires the use of the Inter-
P2MP Segmented Next-Hop Extended Community (S-NH-EC), and the setting Area Point-to-Multipoint (P2MP) Segmented Next-Hop Extended Community
of "Leaf Information Required" L flag in PTA in certain situations. (S-NH-EC) and the setting of the Leaf Information Required (L) flag
In the EVPN case, the requirements around S-NH-EC and the PTA "L" in the PTA in certain situations. In the EVPN case, the requirements
flag differ from [RFC7524] to make the segmentation procedures around the S-NH-EC and the L flag in the PTA differ from [RFC7524] to
transparent to ingress and egress PEs. make the segmentation procedures transparent to ingress and egress
PEs.
[RFC7524] assumes that segmentation happens at area borders. [RFC7524] assumes that segmentation happens at area borders.
However, it could be at "regional" borders, where a region could be a However, it could be at "regional" borders, where a region could be a
sub-area, or even an entire AS plus its external links (Section 6.1). sub-area, or even an entire AS plus its external links (Section 6.1);
That would allow for more flexible deployment scenarios (e.g. for this would allow for more flexible deployment scenarios (e.g., for
single-area provider networks). This document extends the inter-area single-area provider networks). This document extends the inter-area
segmentation to inter-region segmentation for EVPN. segmentation concept to inter-region segmentation for EVPNs.
2.1.1. Reasons for Tunnel Segmentation 2.1. Reasons for Tunnel Segmentation
Tunnel segmentation may be required and/or desired because of Tunnel segmentation may be required and/or desired for administrative
administrative and/or technical reasons. and/or technical reasons.
For example, an MVPN/VPLS/EVPN network may span multiple providers For example, an MVPN/VPLS/EVPN may span multiple providers, and the
and the end-to-end provider tunnels have to be segmented at and end-to-end provider tunnels have to be segmented at and stitched by
stitched by the ASBRs. Different providers may use different tunnel the ASBRs. Different providers may use different tunnel technologies
technologies (e.g., provider A uses Ingress Replication [RFC7988], (e.g., provider A uses ingress replication [RFC7988], provider B uses
provider B uses RSVP-TE P2MP [RFC4875] while provider C uses mLDP RSVP-TE P2MP [RFC4875], and provider C uses Multipoint LDP (mLDP)
[RFC6388]). Even if they use the same tunnel technology like RSVP-TE [RFC6388]). Even if they use the same tunnel technology (e.g., RSVP-
P2MP, it may be impractical to set up the tunnels across provider TE P2MP), it may be impractical to set up the tunnels across provider
boundaries. boundaries.
The same situations may apply between the ASes and/or areas of a The same situations may apply between the ASes and/or areas of a
single provider. For example, the backbone area may use RSVP-TE P2MP single provider. For example, the backbone area may use RSVP-TE P2MP
tunnels while non-backbone areas may use mLDP tunnels. tunnels while non-backbone areas may use mLDP tunnels.
Segmentation can also be used to divide an AS/area into smaller Segmentation can also be used to divide an AS/area into smaller
regions, so that control plane state and/or forwarding plane state/ regions, so that control plane state and/or forwarding plane state/
burden can be limited to that of individual regions. For example, burden can be limited to that of individual regions. For example,
instead of Ingress Replicating to 100 PEs in the entire AS, with instead of ingress-replicating to 100 PEs in the entire AS, with
inter-area segmentation [RFC7524] a PE only needs to replicate to inter-area segmentation [RFC7524], a PE only needs to replicate to
local PEs and ABRs. The ABRs will further replicate to their local PEs and Area Border Routers (ABRs). The ABRs will further
downstream PEs and ABRs. This not only reduces the forwarding plane replicate to their downstream PEs and ABRs. This not only reduces
burden, but also reduces the leaf tracking burden in the control the forwarding plane burden, but also reduces the leaf-tracking
plane. burden in the control plane.
Smaller regions also have the benefit that, in case of tunnel In the case of tunnel aggregation, smaller regions provide the
aggregation, it is easier to find congruence among the segments of benefit of making it easier to find congruence among the segments of
different constituent (service) tunnels and the resulting aggregation different constituent (service) tunnels and the resulting aggregation
(base) tunnel in a region. This leads to better bandwidth (base) tunnel in a region. This leads to better bandwidth
efficiency, because the more congruent they are, the fewer leaves of efficiency, because the more congruent they are, the fewer leaves of
the base tunnel need to discard traffic when a service tunnel's the base tunnel need to discard traffic when a service tunnel's
segment does not need to receive the traffic (yet it is receiving the segment does not need to receive the traffic (yet it is receiving the
traffic due to aggregation). traffic due to aggregation).
Another advantage of the smaller region is smaller BIER [RFC8279] Another advantage of the smaller region is smaller Bit Index Explicit
sub-domains. With BIER, packets carry a BitString, in which the bits Replication (BIER) subdomains [RFC8279]. With BIER, packets carry a
correspond to edge routers that needs to receive traffic. Smaller BitString, in which the bits correspond to edge routers that need to
sub-domains means smaller BitStrings can be used without having to receive traffic. Smaller subdomains means that smaller BitStrings
send multiple copies of the same packet. can be used without having to send multiple copies of the same
packet.
3. Additional Route Types of EVPN NLRI 3. Additional Route Types of EVPN NLRI
[RFC7432] defines the format of EVPN NLRI as the following: [RFC7432] defines the format of EVPN NLRI as follows:
+-----------------------------------+ +-----------------------------------+
| Route Type (1 octet) | | Route Type (1 octet) |
+-----------------------------------+ +-----------------------------------+
| Length (1 octet) | | Length (1 octet) |
+-----------------------------------+ +-----------------------------------+
| Route Type specific (variable) | | Route Type specific (variable) |
+-----------------------------------+ +-----------------------------------+
So far eight route types have been defined in [RFC7432], So far, eight route types have been defined in [RFC7432], [RFC9136],
[I-D.ietf-bess-evpn-prefix-advertisement], and and [RFC9251]:
[I-D.ietf-bess-evpn-igmp-mld-proxy]:
+ 1 - Ethernet Auto-Discovery (A-D) route +=======+=========================================+
+ 2 - MAC/IP Advertisement route | Value | Description |
+ 3 - Inclusive Multicast Ethernet Tag route +=======+=========================================+
+ 4 - Ethernet Segment route | 1 | Ethernet Auto-discovery |
+ 5 - IP Prefix Route +-------+-----------------------------------------+
+ 6 - Selective Multicast Ethernet Tag Route | 2 | MAC/IP Advertisement |
+ 7 - Multicast Join Synch Route +-------+-----------------------------------------+
+ 8 - Multicast Leave Synch Route | 3 | Inclusive Multicast Ethernet Tag |
+-------+-----------------------------------------+
| 4 | Ethernet Segment |
+-------+-----------------------------------------+
| 5 | IP Prefix |
+-------+-----------------------------------------+
| 6 | Selective Multicast Ethernet Tag Route |
+-------+-----------------------------------------+
| 7 | Multicast Membership Report Synch Route |
+-------+-----------------------------------------+
| 8 | Multicast Leave Synch Route |
+-------+-----------------------------------------+
Table 1: Pre-existing Route Types
This document defines three additional route types: This document defines three additional route types:
+ 9 - Per-Region I-PMSI A-D route +=======+=============================+
+ 10 - S-PMSI A-D route | Value | Description |
+ 11 - Leaf A-D route +=======+=============================+
| 9 | Per-Region I-PMSI A-D route |
+-------+-----------------------------+
| 10 | S-PMSI A-D route |
+-------+-----------------------------+
| 11 | Leaf A-D route |
+-------+-----------------------------+
The "Route Type specific" field of the type 9 and type 10 EVPN NLRIs Table 2: New Route Types
starts with a type 1 RD, whose Administrator sub-field MUST match
that of the RD in all current non-Leaf A-D (Section 3.3) EVPN routes
from the same advertising router for a given EVI.
3.1. Per-Region I-PMSI A-D route The "Route Type specific" field of the Type 9 and Type 10 EVPN NLRIs
starts with a Type 1 RD (Route Distinguisher), whose Administrator
sub-field MUST match that of the RD in all current EVPN routes that
are not Leaf A-D routes (Section 3.3), i.e., non-Leaf A-D routes from
the same advertising router for a given EVPN instance (EVI).
The Per-region I-PMSI A-D route has the following format. Its usage 3.1. Per-Region I-PMSI A-D Route
The per-region I-PMSI A-D route has the following format. Its usage
is discussed in Section 6.2. is discussed in Section 6.2.
+-----------------------------------+ +-----------------------------------+
| RD (8 octets) | | RD (8 octets) |
+-----------------------------------+ +-----------------------------------+
| Ethernet Tag ID (4 octets) | | Ethernet Tag ID (4 octets) |
+-----------------------------------+ +-----------------------------------+
| Region ID (8 octets) | | Region ID (8 octets) |
+-----------------------------------+ +-----------------------------------+
The Region ID identifies the region and is encoded just as how an The Region ID identifies the region and is encoded in the same way
Extended Community is encoded, as detailed in Section 6.2. that an EC is encoded, as detailed in Section 6.2.
3.2. S-PMSI A-D route 3.2. S-PMSI A-D Route
The S-PMSI A-D route has the following format: The S-PMSI A-D route has the following format:
+-----------------------------------+ +-----------------------------------+
| RD (8 octets) | | RD (8 octets) |
+-----------------------------------+ +-----------------------------------+
| Ethernet Tag ID (4 octets) | | Ethernet Tag ID (4 octets) |
+-----------------------------------+ +-----------------------------------+
| Multicast Source Length (1 octet) | | Multicast Source Length (1 octet) |
+-----------------------------------+ +-----------------------------------+
| Multicast Source (Variable) | | Multicast Source (variable) |
+-----------------------------------+ +-----------------------------------+
| Multicast Group Length (1 octet) | | Multicast Group Length (1 octet) |
+-----------------------------------+ +-----------------------------------+
| Multicast Group (Variable) | | Multicast Group (variable) |
+-----------------------------------+ +-----------------------------------+
|Originator's Addr Length (1 octet) | |Originator's Addr Length (1 octet) |
+-----------------------------------+ +-----------------------------------+
|Originator's Addr (4 or 16 octets) | |Originator's Addr (4 or 16 octets) |
+-----------------------------------+ +-----------------------------------+
Other than the addition of Ethernet Tag ID and Originator's Addr Other than the addition of the Ethernet Tag ID and Originator's Addr
Length, it is identical to the S-PMSI A-D route as defined in Length fields, it is identical to the S-PMSI A-D route as defined in
[RFC7117]. The procedures in [RFC7117] also apply (including [RFC7117]. The procedures specified in [RFC7117] also apply
wildcard functionality), except that the granularity level is per (including wildcard functionality), except that the granularity level
Ethernet Tag. is per Ethernet Tag.
3.3. Leaf A-D route 3.3. Leaf A-D Route
The Route Type specific field of a Leaf A-D route consists of the The Route Type specific field of a Leaf A-D route consists of the
following: following:
+-----------------------------------+ +-----------------------------------+
| Route Key (variable) | | Route Key (variable) |
+-----------------------------------+ +-----------------------------------+
|Originator's Addr Length (1 octet) | |Originator's Addr Length (1 octet) |
+-----------------------------------+ +-----------------------------------+
|Originator's Addr (4 or 16 octets) | |Originator's Addr (4 or 16 octets) |
+-----------------------------------+ +-----------------------------------+
A Leaf A-D route is originated in response to a PMSI route, which A Leaf A-D route is originated in response to a PMSI route, which
could be an Inclusive Multicast Tag route, a per-region I-PMSI A-D could be an IMET A-D route, a per-region I-PMSI A-D route, an S-PMSI
route, an S-PMSI A-D route, or some other types of routes that may be A-D route, or some other types of routes that may be defined in the
defined in the future that triggers Leaf A-D routes. The Route Key future that trigger Leaf A-D routes. The Route Key is the NLRI of
is the NLRI of the route for which this Leaf A-D route is generated. the route for which this Leaf A-D route is generated.
The general procedures of Leaf A-D route are first specified in The general procedures for Leaf A-D routes were first specified in
[RFC6514] for MVPN. The principles apply to VPLS and EVPN as well. [RFC6514] for MVPNs. The principles therein apply to VPLSs and EVPNs
[RFC7117] has details for VPLS Multicast, and this document points as well. [RFC7117] provides details regarding VPLS multicast, and
out some specifics for EVPN, e.g. in Section 5. this document points out some specifics for EVPNs, e.g., in
Section 5.
4. Selective Multicast 4. Selective Multicast
[I-D.ietf-bess-evpn-igmp-mld-proxy] specifies procedures for EVPN [RFC9251] specifies procedures for EVPN selective forwarding of IP
selective forwarding of IP multicast using SMET routes. It assumes multicast traffic using SMET routes. It assumes that selective
selective forwarding is always used with IR for all flows (though the forwarding is always used with ingress replication for all flows
same signaling can also be used for an ingress PE to find out the set (though the same signaling can also be used for an ingress PE to
of egress PEs for selective forwarding with BIER). An NVE proxies learn the set of egress PEs for selective forwarding with BIER). A
the IGMP/MLD state that it learns on its ACs to (C-S,C-G) or Network Virtualization Edge (NVE) proxies the IGMP/MLD state ("MLD"
(C-*,C-G) SMET routes that advertises to other NVEs, and a receiving stands for "Multicast Listener Discovery") that it learns on its
NVE converts the SMET routes back to IGMP/MLD messages and sends them Attachment Circuits (ACs) to (C-S,C-G) or (C-*,C-G) SMET routes that
out of its ACs. The receiving NVE also uses the SMET routes to are advertised to other NVEs, and a receiving NVE converts the SMET
identify which NVEs need to receive traffic for a particular routes back to IGMP/MLD messages and sends them out of its ACs. The
(C-S,C-G) or (C-*,C-G) to achieve selective forwarding using IR or receiving NVE also uses the SMET routes to identify which NVEs need
BIER. to receive traffic for a particular (C-S,C-G) or (C-*,C-G) to achieve
selective forwarding using ingress replication or BIER.
With the above procedures, selective forwarding is done for all flows With the above procedures, selective forwarding is done for all
and the SMET routes are advertised for all flows. It is possible flows, and the SMET routes are advertised for all flows. It is
that an operator may not want to track all those (C-S, C-G) or possible that an operator may not want to track all those (C-S, C-G)
(C-*,C-G) state on the NVEs, and the multicast traffic pattern allows or (C-*,C-G) states on the NVEs, and the multicast traffic pattern
inclusive forwarding for most flows while selective forwarding is allows inclusive forwarding for most flows while selective forwarding
needed only for a few high-rate flows. For that, or for tunnel types is needed only for a few high-rate flows. For that reason, or for
other than IR/BIER, S-PMSI/Leaf A-D procedures defined for Selective tunnel types other than ingress replication or BIER, S-PMSI/Leaf A-D
Multicast for VPLS in [RFC7117] are used. Other than that different procedures defined for selective multicast for VPLS in [RFC7117] are
route types and formats are specified with EVPN SAFI for S-PMSI A-D used. Other than the fact that different route types and formats are
and Leaf A-D routes (Section 3), all procedures in [RFC7117] with specified with an EVPN SAFI for S-PMSI A-D and Leaf A-D routes
respect to Selective Multicast apply to EVPN as well, including (Section 3), all procedures specified in [RFC7117] with respect to
wildcard procedures. In a nutshell, a source NVE advertises S-PMSI selective multicast apply to EVPNs as well, including wildcard
A-D routes to announce the tunnels used for certain flows, and procedures. In a nutshell, a source NVE advertises S-PMSI A-D routes
receiving NVEs either join the announced PIM/mLDP tunnel or respond to announce the tunnels used for certain flows, and receiving NVEs
with Leaf A-D routes if the Leaf Information Required flag is set in either join the announced PIM/mLDP tunnel or respond with Leaf A-D
the S-PMSI A-D route's PTA (so that the source NVE can include them routes if the L flag is set in the S-PMSI A-D route's PTA (so that
as tunnel leaves). the source NVE can include them as tunnel leaves).
An optimization to the [RFC7117] procedures may be applied. Even if An optimization to the procedures provided in [RFC7117] may be
a source NVE sets the L flag to request Leaf A-D routes, an egress applied. Even if a source NVE sets the L flag to request Leaf A-D
NVE MAY omit the Leaf A-D route if it has already advertised a routes, an egress NVE MAY omit the Leaf A-D route if it has already
corresponding SMET route, and the source NVE MUST use that in lieu of advertised a corresponding SMET route, and the source NVE MUST use
the Leaf A-D route. that in lieu of the Leaf A-D route.
The optional optimizations specified for MVPN in [RFC8534] are also The optional optimizations specified for MVPNs in [RFC8534] are also
applicable to EVPN when the S-PMSI/Leaf A-D routes procedures are applicable to EVPNs when the procedures for S-PMSI/Leaf A-D routes
used for EVPN selective multicast forwarding. are used for EVPN selective multicast forwarding.
5. Inter-AS Segmentation 5. Inter-AS Segmentation
5.1. Differences from Section 7.2.2 of [RFC7117] When Applied to EVPN 5.1. Differences from Section 7.2.2 of RFC 7117 when Applied to EVPNs
The first paragraph of Section 7.2.2.2 of [RFC7117] says: The first paragraph of Section 7.2.2.2 of [RFC7117] says:
"... The best route procedures ensure that if multiple | ... The best route procedures ensure that if multiple ASBRs, in an
ASBRs, in an AS, receive the same Inter-AS A-D route from their EBGP | AS, receive the same Inter-AS A-D route from their EBGP neighbors,
neighbors, only one of these ASBRs propagates this route in Internal | only one of these ASBRs propagates this route in Internal BGP
BGP (IBGP). This ASBR becomes the root of the intra-AS segment of | (IBGP). This ASBR becomes the root of the intra-AS segment of the
the inter-AS tree and ensures that this is the only ASBR that accepts | inter-AS tree and ensures that this is the only ASBR that accepts
traffic into this AS from the inter-AS tree." | traffic into this AS from the inter-AS tree.
The above VPLS behavior requires complicated VPLS specific procedures The above VPLS behavior requires complicated VPLS-specific procedures
for the ASBRs to reach agreement. For EVPN, a different approach is for the ASBRs to reach agreement. For EVPNs, a different approach is
used and the above quoted text is not applicable to EVPN. used; the above text from [RFC7117] is not applicable to EVPNs.
With the different approach for EVPN/MVPN, each ASBR will re- With the different approach for EVPNs/MVPNs, each ASBR will re-
advertise its received Inter-AS A-D route to its IBGP peers and advertise its received Inter-AS A-D route to its IBGP peers and
becomes the root of an intra-AS segment of the inter-AS tree. The becomes the root of an intra-AS segment of the inter-AS tree. The
intra-AS segment rooted at one ASBR is disjoint with another intra-AS intra-AS segment rooted at one ASBR is disjoint from another intra-AS
segment rooted at another ASBR. This is the same as the procedures segment rooted at another ASBR. This is the same as the procedures
for S-PMSI in [RFC7117] itself. for S-PMSI routes in [RFC7117] itself.
The following bullet in Section 7.2.2.2 of [RFC7117] does not apply The following bullet in Section 7.2.2.2 of [RFC7117] does not apply
to EVPN. to EVPNs.
+ If the ASBR uses ingress replication to instantiate the intra-AS | * If the ASBR uses ingress replication to instantiate the intra-
segment of the inter-AS tunnel, the re-advertised route MUST NOT | AS segment of the inter-AS tunnel, the re-advertised route MUST
carry the PMSI Tunnel attribute. | NOT carry the PMSI Tunnel attribute.
The following bullet in Section 7.2.2.2 of [RFC7117]: The following bullet in Section 7.2.2.2 of [RFC7117]:
+ If the ASBR uses a P-multicast tree to instantiate the intra-AS | * If the ASBR uses a P-multicast tree to instantiate the intra-AS
segment of the inter-AS tunnel, the PMSI Tunnel attribute MUST | segment of the inter-AS tunnel, the PMSI Tunnel attribute MUST
contain the identity of the tree that is used to instantiate the | contain the identity of the tree that is used to instantiate
segment (note that the ASBR could create the identity of the tree | the segment (note that the ASBR could create the identity of
prior to the actual instantiation of the segment). If, in order | the tree prior to the actual instantiation of the segment).
to instantiate the segment, the ASBR needs to know the leaves of | If, in order to instantiate the segment, the ASBR needs to know
the tree, then the ASBR obtains this information from the A-D | the leaves of the tree, then the ASBR obtains this information
routes received from other PEs/ASBRs in the ASBR's own AS. | from the A-D routes received from other PEs/ASBRs in the ASBR's
| own AS.
is changed to the following when applied to EVPN: is changed to the following when applied to EVPNs:
"The PMSI Tunnel attribute MUST specify the tunnel for the segment. | * The PTA MUST specify the tunnel for the segment. If and only
If and only if, in order to establish the tunnel, the ASBR needs to | if, in order to establish the tunnel, the ASBR needs to know
know the leaves of the tree, then the ASBR MUST set the L flag to | the leaves of the tree, then the ASBR MUST set the L flag to 1
1 in the PTA to trigger Leaf A-D routes from egress PEs and | in the PTA to trigger Leaf A-D routes from egress PEs and
downstream ASBRs. It MUST be (auto-)configured with an import RT, | downstream ASBRs. It MUST be (auto-)configured with an import
which controls acceptance of leaf A-D routes by the ASBR." | RT, which controls acceptance of Leaf A-D routes by the ASBR.
Accordingly, the following paragraph in Section 7.2.2.4 of [RFC7117]: Accordingly, the following paragraph in Section 7.2.2.4 of [RFC7117]:
"If the received Inter-AS A-D route carries the PMSI Tunnel attribute | If the received Inter-AS A-D route carries the PMSI Tunnel
with the Tunnel Identifier set to RSVP-TE P2MP LSP, then the ASBR | attribute with the Tunnel Identifier set to RSVP-TE P2MP LSP, then
that originated the route MUST establish an RSVP-TE P2MP LSP with the | the ASBR that originated the route MUST establish an RSVP-TE P2MP
local PE/ASBR as a leaf. This LSP MAY have been established before | LSP with the local PE/ASBR as a leaf. This LSP MAY have been
the local PE/ASBR receives the route, or it MAY be established after | established before the local PE/ASBR receives the route, or it MAY
the local PE receives the route." | be established after the local PE receives the route.
is changed to the following when applied to EVPN: is changed to the following when applied to EVPNs:
"If the received Inter-AS A-D route has the L flag set in its PTA, | If the received Inter-AS A-D route has the L flag set in its PTA,
then a receiving PE MUST originate a corresponding Leaf A-D route, | then a receiving PE MUST originate a corresponding Leaf A-D route.
while a receiving ASBR MUST originate a corresponding Leaf A-D route | A receiving ASBR MUST originate a corresponding Leaf A-D route if
if and only if it received and imported one or more corresponding | and only if one of the following conditions is met: (1) it
Leaf A-D routes from its downstream IBGP or EBGP peers, or it has | received and imported one or more corresponding Leaf A-D routes
non-null downstream forwarding state for the PIM/mLDP tunnel that | from its downstream IBGP or EBGP peers or (2) it has non-null
instantiates its downstream intra-AS segment. The targeted ASBR for | downstream forwarding state for the PIM/mLDP tunnel that
the Leaf A-D route, which (re-)advertised the Inter-AS A-D route, | instantiates its downstream intra-AS segment. The targeted ASBR
MUST establish a tunnel to the leaves discovered by the Leaf A-D | for the Leaf A-D route, which (re-)advertised the Inter-AS A-D
routes." | route, MUST establish a tunnel to the leaves discovered by the
| Leaf A-D routes.
5.2. I-PMSI Leaf Tracking 5.2. I-PMSI Leaf Tracking
An ingress PE does not set the L flag in its Inclusive Multicast An ingress PE does not set the L flag in its IMET A-D route's PTA,
Ethernet Tag (IMET) A-D route's PTA, even with Ingress Replication or even with Ingress Replication tunnels or RSVP-TE P2MP tunnels. It
RSVP-TE P2MP tunnels. It does not rely on the Leaf A-D routes to does not rely on the Leaf A-D routes to discover leaves in its AS,
discover leaves in its AS, and Section 11.2 of [RFC7432] explicitly and Section 11.2 of [RFC7432] explicitly states that the L flag must
states that the L flag must be set to zero. be set to 0.
An implementation of [RFC7432] might have used the Originating An implementation of [RFC7432] might have used the Originating
Router's IP Address field of the IMET A-D routes to determine the Router's IP Address field of the IMET A-D routes to determine the
leaves, or might have used the Next Hop field instead. Within the leaves or might have used the Next Hop field instead. Within the
same AS, both will lead to the same result. same AS, both will lead to the same result.
With segmentation, an ingress PE MUST determine the leaves in its AS With segmentation, an ingress PE MUST determine the leaves in its AS
from the BGP next hops in all its received IMET A-D routes, so it from the BGP next hops in all its received IMET A-D routes, so it
does not have to set the L flag set to request Leaf A-D routes. PEs does not have to set the L flag to request Leaf A-D routes. PEs
within the same AS will all have different next hops in their IMET within the same AS will all have different next hops in their IMET
A-D routes (hence will all be considered as leaves), and PEs from A-D routes (and hence will all be considered as leaves), and PEs from
other ASes will have the next hop in their IMET A-D routes set to other ASes will have the next hop in their IMET A-D routes set to
addresses of ASBRs in this local AS, hence only those ASBRs will be addresses of ASBRs in this local AS; hence, only those ASBRs will be
considered as leaves (as proxies for those PEs in other ASes). Note considered as leaves (as proxies for those PEs in other ASes). Note
that in case of Ingress Replication, when an ASBR re-advertises IMET that in the case of ingress replication, when an ASBR re-advertises
A-D routes to IBGP peers, it MUST advertise the same label for all IMET A-D routes to IBGP peers, it MUST advertise the same label for
those for the same Ethernet Tag ID and the same EVI. Otherwise, all those routes for the same Ethernet Tag ID and the same EVI.
duplicated copies will be sent by the ingress PE and received by Otherwise, duplicated copies will be sent by the ingress PE and
egress PEs in other regions. For the same reason, when an ingress PE received by egress PEs in other regions. For the same reason, when
builds its flooding list, if multiple routes have the same (nexthop, an ingress PE builds its flooding list, if multiple routes have the
label) tuple they MUST only be added as a single branch in the same (nexthop, label) tuple, they MUST only be added as a single
flooding list. branch in the flooding list.
5.3. Backward Compatibility 5.3. Backward Compatibility
The above procedures assume that all PEs are upgraded to support the The above procedures assume that all PEs are upgraded to support the
segmentation procedures: segmentation procedures:
o An ingress PE uses the Next Hop and not Originating Router's IP * An ingress PE uses the Next Hop and not the Originating Router's
Address to determine leaves for the I-PMSI tunnel. IP Address to determine leaves for the I-PMSI tunnel.
o An egress PE sends Leaf A-D routes in response to I-PMSI routes, * An egress PE sends Leaf A-D routes in response to I-PMSI routes,
if the PTA has the L flag set by the re-advertising ASBR. if the PTA has the L flag set by the re-advertising ASBR.
o In case of Ingress Replication, when an ingress PE builds its * In the case of ingress replication, when an ingress PE builds its
flooding list, multiple I-PMSI routes may have the same (nexthop, flooding list, multiple I-PMSI routes may have the same (nexthop,
label) tuple and only a single branch for those will be added in label) tuple, and only a single branch for those routes will be
the flooding list. added in the flooding list.
If a deployment has legacy PEs that does not support the above, then If a deployment has legacy PEs that do not support the above, then a
a legacy ingress PE would include all PEs (including those in remote legacy ingress PE would include all PEs (including those in remote
ASes) as leaves of the inclusive tunnel and try to send traffic to ASes) as leaves of the inclusive tunnel and try to send traffic to
them directly (no segmentation), which is either undesired or not them directly (no segmentation), which is either undesirable or
possible; a legacy egress PE would not send Leaf A-D routes so the impossible; a legacy egress PE would not send Leaf A-D routes so the
ASBRs would not know to send external traffic to them. ASBRs would not know to send external traffic to them.
If this backward compatibility problem needs to be addressed, the If this backward-compatibility problem needs to be addressed, the
following procedure MUST be used (see Section 6.2 for per-PE/AS/ following procedure MUST be used (see Section 6.2 for per-PE/AS/
region I-PMSI A-D routes): region I-PMSI A-D routes):
o An upgraded PE indicates in its per-PE I-PMSI A-D route that it * An upgraded PE indicates in its per-PE I-PMSI A-D route that it
supports the new procedures. This is done by setting a flag bit supports the new procedures. This is done by setting a flag bit
in the EVPN Multicast Flags Extended Community. in the EVPN Multicast Flags Extended Community.
o All per-PE I-PMSI A-D routes are restricted to the local AS and * All per-PE I-PMSI A-D routes are restricted to the local AS and
not propagated to external peers. not propagated to external peers.
o The ASBRs in an AS originate per-region I-PMSI A-D routes and * The ASBRs in an AS originate per-region I-PMSI A-D routes and
advertise them to their external peers to specify tunnels used to advertise them to their external peers to specify tunnels used to
carry traffic from the local AS to other ASes. Depending on the carry traffic from the local AS to other ASes. Depending on the
types of tunnels being used, the L flag in the PTA may be set, in types of tunnels being used, the L flag in the PTA may be set, in
which case the downstream ASBRs and upgraded PEs will send Leaf which case the downstream ASBRs and upgraded PEs will send Leaf
A-D routes to pull traffic from their upstream ASBRs. In a A-D routes to pull traffic from their upstream ASBRs. In a
particular downstream AS, one of the ASBRs is elected, based on particular downstream AS, one of the ASBRs is elected, based on
the per-region I-PMSI A-D routes for a particular source AS, to the per-region I-PMSI A-D routes for a particular source AS, to
send traffic from that source AS to legacy PEs in the downstream send traffic from that source AS to legacy PEs in the downstream
AS. The traffic arrives at the elected ASBR on the tunnel AS. The traffic arrives at the elected ASBR on the tunnel
announced in the best per-region I-PMSI A-D route for the source announced in the best per-region I-PMSI A-D route for the source
AS, that the ASBR has selected of all those that it received over AS, as selected by the ASBR from all the routes that it received
EBGP or IBGP sessions. The election procedure is described in over EBGP or IBGP sessions. The election procedure is described
Section 5.3.1. in Section 5.3.1.
o In an ingress/upstream AS, if and only if an ASBR has active * In an ingress/upstream AS, if and only if an ASBR has active
downstream receivers (PEs and ASBRs), which are learned either downstream receivers (PEs and ASBRs), which are learned either
explicitly via Leaf A-D routes or implicitly via PIM join or mLDP explicitly via Leaf A-D routes or implicitly via PIM Join or mLDP
label mapping, the ASBR originates a per-PE I-PMSI A-D route label mapping, the ASBR originates a per-PE I-PMSI A-D route
(i.e., regular Inclusive Multicast Ethernet Tag route) into the (i.e., a regular IMET route) into the local AS and stitches
local AS, and stitches incoming per-PE I-PMSI tunnels into its incoming per-PE I-PMSI tunnels into its per-region I-PMSI tunnel.
per-region I-PMSI tunnel. With this, it gets traffic from local Via this process, it gets traffic from local PEs and sends the
PEs and send to other ASes via the tunnel announced in its per- traffic to other ASes via the tunnel announced in its per-region
region I-PMSI A-D route. I-PMSI A-D route.
Note that, even if there is no backward compatibility issue, the use Note that even if there are no backward-compatibility issues, the use
of per-region I-PMSI has the benefit of keeping all per-PE I-PMSI A-D of per-region I-PMSI A-D routes provides the benefit of keeping all
routes in their local ASes, greatly reducing the flooding of the per-PE I-PMSI A-D routes in their local ASes, greatly reducing the
routes and their corresponding Leaf A-D routes (when needed), and the flooding of the routes and their corresponding Leaf A-D routes (when
number of inter-as tunnels. needed) and reducing the number of inter-AS tunnels.
5.3.1. Designated ASBR Election 5.3.1. Designated ASBR Election
When an ASBR re-advertises a per-region I-PMSI A-D route into an AS When an ASBR re-advertises a per-region I-PMSI A-D route into an AS
in which a designated ASBR needs to be used to forward traffic to the in which a designated ASBR needs to be used to forward traffic to the
legacy PEs in the AS, it MUST include a DF Election EC. The EC and legacy PEs in the AS, it MUST include a Designated Forwarder (DF)
its use is specified in [RFC8584]. The AC-DF bit in the DF Election Election EC. The EC and its use are specified in [RFC8584]. The AC-
EC MUST be cleared. If it is known that no legacy PEs exist in the DF bit in the DF Election EC MUST be cleared. If it is known that no
AS, the ASBR MUST NOT include the EC and MUST remove the DF Election legacy PEs exist in the AS, the ASBR MUST NOT include the EC and MUST
EC if one is carried in the per-region I-PMSI A-D routes that it remove the DF Election EC if one is carried in the per-region I-PMSI
receives. Note that this is done for each set of per-region I-PMSI A-D routes that it receives. Note that this is done for each set of
A-D routes with the same NLRI. per-region I-PMSI A-D routes with the same NLRI.
Based on the procedures in [RFC8584], an election algorithm is Based on the procedures specified in [RFC8584], an election algorithm
determined according to the DF Election ECs carried in the set of is determined according to the DF Election ECs carried in the set of
per-region I-PMSI routes of the same NLRI re-adverised into the AS. per-region I-PMSI routes of the same NLRI re-advertised into the AS.
The algorithm is then applied to a candidate list, which is the set The algorithm is then applied to a candidate list, which is the set
of ASBRs that re-advertised the per-region I-PMSI routes of the same of ASBRs that re-advertised the per-region I-PMSI routes of the same
NLRI carrying the DF Election EC. NLRI carrying the DF Election EC.
6. Inter-Region Segmentation 6. Inter-Region Segmentation
6.1. Area/AS vs. Region 6.1. Area/AS vs. Region
[RFC7524] is for MVPN/VPLS inter-area segmentation and does not [RFC7524] addresses MVPN/VPLS inter-area segmentation and does not
explicitly cover EVPN. However, if "area" is replaced by "region" explicitly cover EVPNs. However, if "area" is replaced by "region"
and "ABR" is replaced by "RBR" (Regional Border Router) then and "ABR" is replaced by "RBR" (Regional Border Router), then
everything still works, and can be applied to EVPN as well. everything still works and can be applied to EVPNs as well.
A region can be a sub-area, or can be an entire AS including its A region can be a sub-area, or it can be an entire AS, including its
external links. Instead of automatic region definition based on IGP external links. Instead of automatically defining a region based on
areas, a region would be defined as a BGP peer group. In fact, even IGP areas, a region would be defined as a BGP peer group. In fact,
with IGP area based region definition, a BGP peer group listing the even with a region definition based on an IGP area, a BGP peer group
PEs and ABRs in an area is still needed. listing the PEs and ABRs in an area is still needed.
Consider the following example diagram for inter-as segmentation: Consider the following example diagram for inter-AS segmentation:
--------- ------ --------- --------- ------ ---------
/ \ / \ / \ / \ / \ / \
/ \ / \ / \ / \ / \ / \
| PE1 o ASBR1 -- ASBR2 ASBR3 -- ASBR4 o PE2 | | PE1 o ASBR1 -- ASBR2 ASBR3 -- ASBR4 o PE2 |
\ / \ / \ / \ / \ / \ /
\ / \ / \ / \ / \ / \ /
--------- ------ --------- --------- ------ ---------
AS 100 AS 200 AS 300 AS 100 AS 200 AS 300
|-----------|--------|---------|--------|------------| |-----------|--------|---------|--------|------------|
segment1 segment2 segment3 segment4 segment5 segment1 segment2 segment3 segment4 segment5
The inter-as segmentation procedures specified so far ([RFC6513] The inter-AS segmentation procedures specified so far ([RFC6513],
[RFC6514], [RFC7117], and Section 5 of this document) require all [RFC6514], [RFC7117], and Section 5 of this document) require all
ASBRs to be involved, and Ingress Replication is used between two ASBRs to be involved, and ingress replication is used between two
ASBRs in different ASes. ASBRs in different ASes.
In the above diagram, it's possible that ASBR1/4 does not support In the above diagram, it's possible that ASBR1/4 does not support
segmentation, and the provider tunnels in AS 100/300 can actually segmentation, and the provider tunnels in AS 100/300 can actually
extend across the external link. In this case, the inter-region extend across the external link. In this case, the inter-region
segmentation procedures can be used instead - a region is the entire segmentation procedures can be used instead -- a region is the entire
(AS100 + ASBR1-ASBR2 link) or (AS300 + ASBR3-ASBR4 link). ASBR2/3 AS100 plus the ASBR1-ASBR2 link or the entire AS300 plus the
would be the RBRs, and ASBR1/4 will just be a transit core router ASBR3-ASBR4 link. ASBR2/3 would be the RBRs, and ASBR1/4 will just
with respect to provider tunnels. be a transit core router with respect to provider tunnels.
As illustrated in the diagram below, ASBR2/3 will establish a As illustrated in the diagram below, ASBR2/3 will establish a
multihop EBGP session with either a RR or directly with PEs in the multihop EBGP session, either with a Route Reflector (RR) or directly
neighboring AS. I/S-PMSI A-D routes from ingress PEs will not be with PEs in the neighboring AS. I/S-PMSI A-D routes from ingress PEs
processed by ASBR1/4. When ASBR2 re-advertises the routes into AS will not be processed by ASBR1/4. When ASBR2 re-advertises the
200, it changes the next hop to its own address and changes PTA to routes into AS 200, it changes the next hop to its own address and
specify the tunnel type/identification in its own AS. When ASBR3 re- changes its PTA to specify the tunnel type/identification in its own
advertises I/S-PMSI A-D routes into the neighboring AS 300, it AS. When ASBR3 re-advertises I/S-PMSI A-D routes into the
changes the next hop to its own address and changes PTA to specify neighboring AS 300, it changes the next hop to its own address and
the tunnel type/identification in the neighboring region. Now the changes its PTA to specify the tunnel type/identification in the
segment is rooted at ASBR3 and extends across the external link to neighboring region. Now, the segment is rooted at ASBR3 and extends
PEs. across the external link to PEs.
--------- ------ --------- --------- ------ ---------
/ RR....\.mh-ebpg / \ mh-ebgp/....RR \ / RR....\.mh-ebpg / \ mh-ebgp/....RR \
/ : \ `. / \ .' / : \ / : \ `. / \ .' / : \
| PE1 o ASBR1 -- ASBR2 ASBR3 -- ASBR4 o PE2 | | PE1 o ASBR1 -- ASBR2 ASBR3 -- ASBR4 o PE2 |
\ / \ / \ / \ / \ / \ /
\ / \ / \ / \ / \ / \ /
--------- ------ --------- --------- ------ ---------
AS 100 AS 200 AS 300 AS 100 AS 200 AS 300
|-------------------|----------|---------------------| |-------------------|----------|---------------------|
segment 1 segment 2 segment 3 segment 1 segment 2 segment 3
6.2. Per-region Aggregation 6.2. Per-Region Aggregation
Notice that every I/S-PMSI route from each PE will be propagated Notice that every I/S-PMSI route from each PE will be propagated
throughout all the ASes or regions. They may also trigger throughout all the ASes or regions. They may also trigger
corresponding Leaf A-D routes depending on the types of tunnels used corresponding Leaf A-D routes, depending on the types of tunnels used
in each region. This may become too many - routes and corresponding in each region. This may result in too many routes and corresponding
tunnels. To address this concern, the I-PMSI routes from all PEs in tunnels. To address this concern, the I-PMSI routes from all PEs in
a AS/region can be aggregated into a single I-PMSI route originated an AS/region can be aggregated into a single I-PMSI route originated
from the RBRs, and traffic from all those individual I-PMSI tunnels from the RBRs, and traffic from all those individual I-PMSI tunnels
will be switched into the single I-PMSI tunnel. This is like the will be switched into the single I-PMSI tunnel. This is like the
MVPN Inter-AS I-PMSI route originated by ASBRs. MVPN Inter-AS I-PMSI route originated by ASBRs.
The MVPN Inter-AS I-PMSI A-D route can be better called as per-AS The MVPN Inter-AS I-PMSI A-D route can be better called a "per-AS
I-PMSI A-D route, to be compared against the (per-PE) Intra-AS I-PMSI I-PMSI A-D route", to be compared against the (per-PE) Intra-AS
A-D routes originated by each PE. In this document we will call it I-PMSI A-D routes originated by each PE. In this document, we will
as per-region I-PMSI A-D route, in case we want to apply the call it a "per-region I-PMSI A-D route" in cases where we want to
aggregation at regional level. The per-PE I-PMSI routes will not be apply aggregation at the regional level. The per-PE I-PMSI routes
propagated to other regions. If multiple RBRs are connected to a will not be propagated to other regions. If multiple RBRs are
region, then each will advertise such a route, with the same Region connected to a region, then each will advertise such a route, with
ID and Ethernet Tag ID (Section 3.1). Similar to the per-PE I-PMSI the same Region ID and Ethernet Tag ID (Section 3.1). Similar to the
A-D routes, RBRs/PEs in a downstream region will each select a best per-PE I-PMSI A-D routes, RBRs/PEs in a downstream region will each
one from all those re-advertised by the upstream RBRs, hence will select the best route from all those re-advertised by the upstream
only receive traffic injected by one of them. RBRs and hence will only receive traffic injected by one of them.
MVPN does not aggregate S-PMSI routes from all PEs in an AS like it MVPNs do not aggregate S-PMSI routes from all PEs in an AS like they
does for I-PMSIs routes, because the number of PEs that will do for I-PMSI routes, because the number of PEs that will advertise
advertise S-PMSI routes for the same (s,g) or (*,g) is small. This S-PMSI routes for the same (S,G) or (*,G) is small. This is also the
is also the case for EVPN, i.e., there is no per-region S-PMSI case for EVPNs, i.e., there are no per-region S-PMSI routes.
routes.
Notice that per-region I-PMSI routes can also be used to address Notice that per-region I-PMSI routes can also be used to address
backwards compatibility issue, as discussed in Section 5.3. backward-compatibility issues, as discussed in Section 5.3.
The Region ID in the per-region I-PMSI route's NLRI is encoded like The Region ID in the per-region I-PMSI route's NLRI is encoded like
an EC. For example, the Region ID can encode an AS number or area ID an EC. For example, the Region ID can encode an AS number or area ID
in the following EC format: in the following EC format:
o For a two-octet AS number, a Transitive Two-Octet AS-Specific EC * For a two-octet AS number, a Transitive Two-Octet AS-specific EC
of sub-type 0x09 (Source AS), with the Global Administrator sub- of sub-type 0x09 (Source AS), with the Global Administrator sub-
field set to the AS number and the Local Administrator sub-field field set to the AS number and the Local Administrator sub-field
set to 0. set to 0.
o For a four-octet AS number, a Transitive Four-Octet AS-Specific EC * For a four-octet AS number, a Transitive Four-Octet AS-specific EC
of sub-type 0x09 (Source AS), with the Global Administrator sub- of sub-type 0x09 (Source AS), with the Global Administrator sub-
field set to the AS number and the Local Administrator sub-field field set to the AS number and the Local Administrator sub-field
set to 0. set to 0.
o For an area ID, a Transitive IPv4-Address-Specific EC of any sub- * For an area ID, a Transitive IPv4-Address-specific EC of any sub-
type, with the Global Administrator sub-field set to the area ID type, with the Global Administrator sub-field set to the area ID
and the Local Administrator sub-field set to 0. and the Local Administrator sub-field set to 0.
Uses of other EC encoding MAY be allowed as long as it uniquely The use of other EC encodings MAY be allowed as long as they uniquely
identifies the region and the RBRs for the same region uses the same identify the region and the RBRs for the same region use the same
Region ID. Region ID.
6.3. Use of S-NH-EC 6.3. Use of S-NH-EC
[RFC7524] specifies the use of S-NH-EC because it does not allow ABRs [RFC7524] specifies the use of the S-NH-EC because it does not allow
to change the BGP next hop when they re-advertise I/S-PMSI A-D routes ABRs to change the BGP next hop when they re-advertise I/S-PMSI A-D
to downstream areas. That is only to be consistent with the MVPN routes to downstream areas. That behavior is only to be consistent
Inter-AS I-PMSI A-D routes, whose next hop must not be changed when with the MVPN Inter-AS I-PMSI A-D routes, whose next hop must not be
they're re-advertised by the segmenting ABRs for reasons specific to changed when they're re-advertised by the segmenting ABRs for reasons
MVPN. For EVPN, it is perfectly fine to change the next hop when specific to MVPNs. For EVPNs, it is perfectly fine to change the
RBRs re-advertise the I/S-PMSI A-D routes, instead of relying on S- next hop when RBRs re-advertise the I/S-PMSI A-D routes, instead of
NH-EC. As a result, this document specifies that RBRs change the BGP relying on the S-NH-EC. As a result, this document specifies that
next hop when they re-advertise I/S-PMSI A-D routes and do not use S- RBRs change the BGP next hop when they re-advertise I/S-PMSI A-D
NH-EC. The advantage of this is that neither ingress nor egress PEs routes and do not use the S-NH-EC. This provides the advantage that
need to understand/use S-NH-EC, and a consistent procedure (based on neither ingress PEs nor egress PEs need to understand/use the S-NH-
BGP next hop) is used for both inter-as and inter-region EC, and a consistent procedure (based on BGP next hops) is used for
segmentation. both inter-AS and inter-region segmentation.
If a downstream PE/RBR needs to originate Leaf A-D routes, it If a downstream PE/RBR needs to originate Leaf A-D routes, it
constructs an IP-based Route Target Extended Community by placing the constructs an IP-based Route Target Extended Community by placing the
IP address carried in the Next Hop of the received I/S-PMSI A-D route IP address carried in the Next Hop of the received I/S-PMSI A-D route
in the Global Administrator field of the Community, with the Local in the Global Administrator field of the extended community, with the
Administrator field of this Community set to 0 and setting the Local Administrator field of this extended community set to 0, and
Extended Communities attribute of the Leaf A-D route to that also setting the Extended Communities attribute of the Leaf A-D route
Community. to that extended community.
Similar to [RFC7524], the upstream RBR MUST (auto-)configure a RT Similar to [RFC7524], the upstream RBR MUST (auto-)configure an RT
with the Global Administrator field set to the Next Hop in the re- with the Global Administrator field set to the Next Hop in the re-
advertised I/S-PMSI A-D route and with the Local Administrator field advertised I/S-PMSI A-D route and with the Local Administrator field
set to 0. With this, the mechanisms specified in [RFC4684] for set to 0. Using this technique, the mechanisms specified in
constrained BGP route distribution can be used along with this [RFC4684] for constrained BGP route distribution can be used along
specification to ensure that only the needed PE/ABR will have to with this specification to ensure that only the needed PE/ABR will
process a said Leaf A-D route. have to process a particular Leaf A-D route.
6.4. Ingress PE's I-PMSI Leaf Tracking 6.4. Ingress PE's I-PMSI Leaf Tracking
[RFC7524] specifies that when an ingress PE/ASBR (re-)advertises an [RFC7524] specifies that when an ingress PE/ASBR (re-)advertises a
VPLS I-PMSI A-D route, it sets the L flag to 1 in the route's PTA. VPLS I-PMSI A-D route, it sets the L flag to 1 in the route's PTA.
Similar to the inter-as case, this is actually not really needed for Similar to the inter-AS case, this is actually not really needed for
EVPN. To be consistent with the inter-as case, the ingress PE does EVPNs. To be consistent with the inter-AS case, the ingress PE does
not set the L flag in its originated I-PMSI A-D routes, and not set the L flag in its originated I-PMSI A-D routes, and it
determines the leaves based on the BGP next hops in its received determines the leaves based on the BGP next hops in its received
I-PMSI A-D routes, as specified in Section 5.2. I-PMSI A-D routes, as specified in Section 5.2.
The same backward compatibility issue exists, and the same solution The same backward-compatibility issue exists, and the same solution
as in the inter-as case applies, as specified in Section 5.3. as that for the inter-AS case applies, as specified in Section 5.3.
7. Multi-homing Support 7. Multihoming Support
To support multi-homing with segmentation, ESI labels SHOULD be To support multihoming with segmentation, Ethernet Segment Identifier
allocated from "Domain-wide Common Block" (DCB) (ESI) labels SHOULD be allocated from a "Domain-wide Common Block"
[I-D.ietf-bess-mvpn-evpn-aggregation-label] for all tunnel types (DCB) [RFC9573] for all tunnel types, including Ingress Replication
including Ingress Replication. Via means outside the scope of this tunnels [RFC7988]. Via means outside the scope of this document, PEs
document, PEs know that ESI labels are from DCB and then existing know that ESI labels are from a DCB, and existing multihoming
multi-homing procedures work as is (whether a multi-homed Ethernet procedures will then work "as is" (whether a multihomed Ethernet
Segment spans across segmentation regions or not). Segment spans segmentation regions or not).
Not using DCB-allocated ESI labels is outside the scope of this Not using DCB-allocated ESI labels is outside the scope of this
document. document.
8. IANA Considerations 8. IANA Considerations
IANA has temporarily assigned the following new EVPN route types in IANA has assigned the following new EVPN route types in the "EVPN
the EVPN Route Types registry: Route Types" registry:
o 9 - Per-Region I-PMSI A-D route +=======+=============================+===========+
| Value | Description | Reference |
+=======+=============================+===========+
| 9 | Per-Region I-PMSI A-D route | RFC 9572 |
+-------+-----------------------------+-----------+
| 10 | S-PMSI A-D route | RFC 9572 |
+-------+-----------------------------+-----------+
| 11 | Leaf A-D route | RFC 9572 |
+-------+-----------------------------+-----------+
o 10 - S-PMSI A-D route Table 3: New Route Types
o 11 - Leaf A-D route IANA has assigned one flag bit from the "Multicast Flags Extended
Community" registry created by [RFC9251]:
This document requests IANA to assign one flag bit from the EVPN +=====+======================+===========+===================+
Multicast Flags Extended Community Flags registry to be created in | Bit | Name | Reference | Change Controller |
[draft-ietf-bess-evpn-igmp-mld-proxy]: +=====+======================+===========+===================+
| 8 | Segmentation Support | RFC 9572 | IETF |
+-----+----------------------+-----------+-------------------+
o Bit-S - Segmentation Procedure Support Table 4: New Multicast Flag
9. Security Considerations 9. Security Considerations
The Selective Forwarding procedures via S-PMSI/Leaf A-D routes in The procedures specified in this document for selective forwarding
this document are based on the same procedures for MVPN [RFC6513] via S-PMSI/Leaf A-D routes are based on the same procedures as those
[RFC6514] and VPLS Multicast [RFC7117]. The tunnel segmentation used for MVPNs [RFC6513] [RFC6514] and VPLS multicast [RFC7117]. The
procedures in this document are based on the similar procedures for procedures for tunnel segmentation as specified in this document are
MVPN inter-AS [RFC6514] and inter-area [RFC7524] tunnel segmentation, based on similar procedures used for MVPN inter-AS tunnel
and procedures for VPLS Multicast [RFC7117] inter-as tunnel segmentation [RFC6514] and inter-area tunnel segmentation [RFC7524],
segmentation. When applied to EVPN, they do not introduce new as well as procedures for VPLS multicast inter-AS tunnel segmentation
security concerns besides what have been discussed in [RFC6513], [RFC7117]. When applied to EVPNs, they do not introduce new security
[RFC6514], [RFC7117], and [RFC7524]. They also do not introduce new concerns beyond those discussed in [RFC6513], [RFC6514], [RFC7117],
security concerns compared to [RFC7432]. and [RFC7524]. They also do not introduce new security concerns
compared to [RFC7432].
10. Acknowledgements
The authors thank Eric Rosen, John Drake, and Ron Bonica for their
comments and suggestions.
11. Contributors
The following also contributed to this document through their earlier
work in EVPN selective multicast.
Junlin Zhang
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: jackey.zhang@huawei.com
Zhenbin Li
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: lizhenbin@huawei.com
12. References
12.1. Normative References
[I-D.ietf-bess-evpn-igmp-mld-proxy] 10. References
Sajassi, A., Thoria, S., Mishra, M., Drake, J., and W.
Lin, "IGMP and MLD Proxy for EVPN", draft-ietf-bess-evpn-
igmp-mld-proxy-14 (work in progress), October 2021.
[I-D.ietf-bess-mvpn-evpn-aggregation-label] 10.1. Normative References
Zhang, Z., Rosen, E., Lin, W., Li, Z., and I. Wijnands,
"MVPN/EVPN Tunnel Aggregation with Common Labels", draft-
ietf-bess-mvpn-evpn-aggregation-label-06 (work in
progress), April 2021.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/ [RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
2012, <https://www.rfc-editor.org/info/rfc6513>. 2012, <https://www.rfc-editor.org/info/rfc6513>.
skipping to change at page 19, line 36 skipping to change at line 889
"Explicit Tracking with Wildcard Routes in Multicast VPN", "Explicit Tracking with Wildcard Routes in Multicast VPN",
RFC 8534, DOI 10.17487/RFC8534, February 2019, RFC 8534, DOI 10.17487/RFC8534, February 2019,
<https://www.rfc-editor.org/info/rfc8534>. <https://www.rfc-editor.org/info/rfc8534>.
[RFC8584] Rabadan, J., Ed., Mohanty, S., Ed., Sajassi, A., Drake, [RFC8584] Rabadan, J., Ed., Mohanty, S., Ed., Sajassi, A., Drake,
J., Nagaraj, K., and S. Sathappan, "Framework for Ethernet J., Nagaraj, K., and S. Sathappan, "Framework for Ethernet
VPN Designated Forwarder Election Extensibility", VPN Designated Forwarder Election Extensibility",
RFC 8584, DOI 10.17487/RFC8584, April 2019, RFC 8584, DOI 10.17487/RFC8584, April 2019,
<https://www.rfc-editor.org/info/rfc8584>. <https://www.rfc-editor.org/info/rfc8584>.
12.2. Informative References [RFC9251] Sajassi, A., Thoria, S., Mishra, M., Patel, K., Drake, J.,
and W. Lin, "Internet Group Management Protocol (IGMP) and
Multicast Listener Discovery (MLD) Proxies for Ethernet
VPN (EVPN)", RFC 9251, DOI 10.17487/RFC9251, June 2022,
<https://www.rfc-editor.org/info/rfc9251>.
[I-D.ietf-bess-evpn-prefix-advertisement] [RFC9573] Zhang, Z., Rosen, E., Lin, W., Li, Z., and IJ. Wijnands,
Rabadan, J., Henderickx, W., Drake, J. E., Lin, W., and A. "MVPN/EVPN Tunnel Aggregation with Common Labels",
Sajassi, "IP Prefix Advertisement in Ethernet VPN (EVPN)", RFC 9573, DOI 10.17487/RFC9573, May 2024,
draft-ietf-bess-evpn-prefix-advertisement-11 (work in <https://www.rfc-editor.org/info/rfc9573>.
progress), May 2018.
10.2. Informative References
[RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk, [RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
R., Patel, K., and J. Guichard, "Constrained Route R., Patel, K., and J. Guichard, "Constrained Route
Distribution for Border Gateway Protocol/MultiProtocol Distribution for Border Gateway Protocol/MultiProtocol
Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684, Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684,
November 2006, <https://www.rfc-editor.org/info/rfc4684>. November 2006, <https://www.rfc-editor.org/info/rfc4684>.
[RFC4875] Aggarwal, R., Ed., Papadimitriou, D., Ed., and S. [RFC4875] Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
Yasukawa, Ed., "Extensions to Resource Reservation Yasukawa, Ed., "Extensions to Resource Reservation
skipping to change at page 20, line 29 skipping to change at line 933
Replication Tunnels in Multicast VPN", RFC 7988, Replication Tunnels in Multicast VPN", RFC 7988,
DOI 10.17487/RFC7988, October 2016, DOI 10.17487/RFC7988, October 2016,
<https://www.rfc-editor.org/info/rfc7988>. <https://www.rfc-editor.org/info/rfc7988>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279, Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017, DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>. <https://www.rfc-editor.org/info/rfc8279>.
[RFC9136] Rabadan, J., Ed., Henderickx, W., Drake, J., Lin, W., and
A. Sajassi, "IP Prefix Advertisement in Ethernet VPN
(EVPN)", RFC 9136, DOI 10.17487/RFC9136, October 2021,
<https://www.rfc-editor.org/info/rfc9136>.
Acknowledgements
The authors thank Eric Rosen, John Drake, and Ron Bonica for their
comments and suggestions.
Contributors
The following people also contributed to this document through their
earlier work in EVPN selective multicast.
Junlin Zhang
Huawei Technologies
Huawei Bld., No. 156 Beiqing Rd.
Beijing
100095
China
Email: jackey.zhang@huawei.com
Zhenbin Li
Huawei Technologies
Huawei Bld., No. 156 Beiqing Rd.
Beijing
100095
China
Email: lizhenbin@huawei.com
Authors' Addresses Authors' Addresses
Zhaohui Zhang Zhaohui Zhang
Juniper Networks Juniper Networks
Email: zzhang@juniper.net
EMail: zzhang@juniper.net
Wen Lin Wen Lin
Juniper Networks Juniper Networks
Email: wlin@juniper.net
EMail: wlin@juniper.net
Jorge Rabadan Jorge Rabadan
Nokia Nokia
Email: jorge.rabadan@nokia.com
EMail: jorge.rabadan@nokia.com
Keyur Patel Keyur Patel
Arrcus Arrcus
Email: keyur@arrcus.com
EMail: keyur@arrcus.com
Ali Sajassi Ali Sajassi
Cisco Systems Cisco Systems
Email: sajassi@cisco.com
EMail: sajassi@cisco.com
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