draft-ietf-bess-evpn-igmp-mld-proxy-03.txt   draft-ietf-bess-evpn-igmp-mld-proxy-04.txt 
BESS Working Group Ali Sajassi BESS Working Group Ali Sajassi
Internet-Draft Samir Thoria Internet-Draft Samir Thoria
Intended Status: Standards Track Cisco Intended Status: Standards Track Cisco
Keyur Patel Keyur Patel
Derek Yeung
Arrcus Arrcus
John Drake John Drake
Wen Lin Wen Lin
Juniper Juniper
Expires: December 12, 2019 June 10, 2019 Expires: April 2, 2020 September 30, 2019
IGMP and MLD Proxy for EVPN IGMP and MLD Proxy for EVPN
draft-ietf-bess-evpn-igmp-mld-proxy-03 draft-ietf-bess-evpn-igmp-mld-proxy-04
Abstract Abstract
Ethernet Virtual Private Network (EVPN) solution [RFC 7432] is Ethernet Virtual Private Network (EVPN) solution is becoming
becoming pervasive in data center (DC) applications for Network pervasive in data center (DC) applications for Network Virtualization
Virtualization Overlay (NVO) and DC interconnect (DCI) services, and Overlay (NVO) and DC interconnect (DCI) services, and in service
in service provider (SP) applications for next generation virtual provider (SP) applications for next generation virtual private LAN
private LAN services. services.
This draft describes how to support efficiently endpoints running This draft describes how to support efficiently endpoints running
IGMP for the above services over an EVPN network by incorporating IGMP for the above services over an EVPN network by incorporating
IGMP proxy procedures on EVPN PEs. IGMP proxy procedures on EVPN PEs.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
skipping to change at page 2, line 24 skipping to change at page 2, line 23
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Specification of Requirements . . . . . . . . . . . . . . . . . 5
2 IGMP Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Proxy Reporting . . . . . . . . . . . . . . . . . . . . . . 6 4 IGMP/MLD Proxy . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.1 IGMP Membership Report Advertisement in BGP . . . . . . 7 4.1 Proxy Reporting . . . . . . . . . . . . . . . . . . . . . . 6
2.1.1 IGMP Leave Group Advertisement in BGP . . . . . . . . . 8 4.1.1 IGMP/MLD Membership Report Advertisement in BGP . . . . 7
2.2 Proxy Querier . . . . . . . . . . . . . . . . . . . . . . . 9 4.1.2 IGMP/MLD Leave Group Advertisement in BGP . . . . . . . 8
3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2 Proxy Querier . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 PE with only attached hosts/VMs for a given subnet . . . . . 10 5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 PE with mixed of attached hosts/VMs and multicast source . . 11 5.1 PE with only attached hosts/VMs for a given subnet . . . . . 10
3.3 PE with mixed of attached hosts/VMs, multicast source and 5.2 PE with a mix of attached hosts/VMs and multicast source . . 11
router . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5.3 PE with a mix of attached hosts/VMs, a multicast source
4 All-Active Multi-Homing . . . . . . . . . . . . . . . . . . . . 11 and a router . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 Local IGMP Join Synchronization . . . . . . . . . . . . . . 11 6 All-Active Multi-Homing . . . . . . . . . . . . . . . . . . . . 11
4.2 Local IGMP Leave Group Synchronization . . . . . . . . . . . 12 6.1 Local IGMP/MLD Join Synchronization . . . . . . . . . . . . 12
4.2.1 Remote Leave Group Synchronization . . . . . . . . . . . 13 6.2 Local IGMP/MLD Leave Group Synchronization . . . . . . . . . 12
4.2.2 Common Leave Group Synchronization . . . . . . . . . . . 13 6.2.1 Remote Leave Group Synchronization . . . . . . . . . . . 13
4.3 Mass Withdraw of Multicast join Sync route in case of 6.2.2 Common Leave Group Synchronization . . . . . . . . . . . 14
6.3 Mass Withdraw of Multicast join Sync route in case of
failure . . . . . . . . . . . . . . . . . . . . . . . . . . 14 failure . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5 Single-Active Multi-Homing . . . . . . . . . . . . . . . . . . . 14 7 Single-Active Multi-Homing . . . . . . . . . . . . . . . . . . . 14
6 Selective Multicast Procedures for IR tunnels . . . . . . . . . 14 8 Selective Multicast Procedures for IR tunnels . . . . . . . . . 14
7 BGP Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 15 9 BGP Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7.1 Selective Multicast Ethernet Tag Route . . . . . . . . . . . 15 9.1 Selective Multicast Ethernet Tag Route . . . . . . . . . . . 15
7.1.1 Constructing the Selective Multicast Ethernet Tag 9.1.1 Constructing the Selective Multicast Ethernet Tag
route . . . . . . . . . . . . . . . . . . . . . . . . . 17 route . . . . . . . . . . . . . . . . . . . . . . . . . 17
7.1.2 Default Selective Multicast Route . . . . . . . . . . . 18 9.1.2 Default Selective Multicast Route . . . . . . . . . . . 18
7.2 Multicast Join Synch Route . . . . . . . . . . . . . . . . 19 9.2 Multicast Join Synch Route . . . . . . . . . . . . . . . . 19
7.2.1 Constructing the Multicast Join Synch Route . . . . . . 21 9.2.1 Constructing the Multicast Join Synch Route . . . . . . 21
7.3 Multicast Leave Synch Route . . . . . . . . . . . . . . . . 22 9.3 Multicast Leave Synch Route . . . . . . . . . . . . . . . . 22
7.3.1 Constructing the Multicas Leave Synch Route . . . . . . 24 9.3.1 Constructing the Multicast Leave Synch Route . . . . . 24
7.4 Multicast Flags Extended Community . . . . . . . . . . . . . 25 9.4 Multicast Flags Extended Community . . . . . . . . . . . . . 25
7.5 EVI-RT Extended Community . . . . . . . . . . . . . . . . . 26 9.5 EVI-RT Extended Community . . . . . . . . . . . . . . . . . 26
7.6 Rewriting of RT ECs and EVI-RT ECs by ASBRs . . . . . . . . 28 9.6 Rewriting of RT ECs and EVI-RT ECs by ASBRs . . . . . . . . 29
8 IGMP/MLD Immediate leave . . . . . . . . . . . . . . . . . . . 28 10 IGMP/MLD Immediate Leave . . . . . . . . . . . . . . . . . . . 29
9 IGMP Version 1 membership request . . . . . . . . . . . . . . . 29 11 IGMP Version 1 Membership Request . . . . . . . . . . . . . . . 29
10 Security Considerations . . . . . . . . . . . . . . . . . . . 29 12 Security Considerations . . . . . . . . . . . . . . . . . . . . 30
11 IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 13 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 30
12 References . . . . . . . . . . . . . . . . . . . . . . . . . . 30 14 References . . . . . . . . . . . . . . . . . . . . . . . . . . 30
12.1 Normative References . . . . . . . . . . . . . . . . . . . 30 14.1 Normative References . . . . . . . . . . . . . . . . . . . 30
12.2 Informative References . . . . . . . . . . . . . . . . . . 30 14.2 Informative References . . . . . . . . . . . . . . . . . . 31
13 Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 30 15 Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . 31
14 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 30 16 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 32
1 Introduction 1 Introduction
Ethernet Virtual Private Network (EVPN) solution [RFC 7432] is Ethernet Virtual Private Network (EVPN) solution [RFC7432] is
becoming pervasive in data center (DC) applications for Network becoming pervasive in data center (DC) applications for Network
Virtualization Overlay (NVO) and DC interconnect (DCI) services, and Virtualization Overlay (NVO) and DC interconnect (DCI) services, and
in service provider (SP) applications for next generation virtual in service provider (SP) applications for next generation virtual
private LAN services. private LAN services.
In DC applications, a point of delivery (POD) can consist of a In DC applications, a point of delivery (POD) can consist of a
collection of servers supported by several top of rack (TOR) and collection of servers supported by several top of rack (TOR) and
Spine switches. This collection of servers and switches are self Spine switches. This collection of servers and switches are self
contained and may have their own control protocol for intra-POD contained and may have their own control protocol for intra-POD
communication and orchestration. However, EVPN is used as way of communication and orchestration. However, EVPN is used as standard
standard inter-POD communication for both intra-DC and inter-DC. A way of inter-POD communication for both intra-DC and inter-DC. A
subnet can span across multiple PODs and DCs. EVPN provides robust subnet can span across multiple PODs and DCs. EVPN provides robust
multi-tenant solution with extensive multi-homing capabilities to multi-tenant solution with extensive multi-homing capabilities to
stretch a subnet (e.g., VLAN) across multiple PODs and DCs. There can stretch a subnet (VLAN) across multiple PODs and DCs. There can be
be many hosts/VMs (e.g., several hundreds) attached to a subnet that many hosts/VMs ( several hundreds) attached to a subnet that is
is stretched across several PODs and DCs. stretched across several PODs and DCs.
These hosts/VMs express their interests in multicast groups on a These hosts/VMs express their interests in multicast groups on a
given subnet/VLAN by sending IGMP membership reports (Joins) for given subnet/VLAN by sending IGMP membership reports (Joins) for
their interested multicast group(s). Furthermore, an IGMP router their interested multicast group(s). Furthermore, an IGMP router
periodically sends membership queries to find out if there are hosts periodically sends membership queries to find out if there are hosts
on that subnet still interested in receiving multicast traffic for on that subnet that are still interested in receiving multicast
that group. The IGMP/MLD Proxy solution described in this draft has traffic for that group. The IGMP/MLD Proxy solution described in this
three objectives to accomplish: draft accomplishes has three objectives:
1) Reduce flooding of IGMP messages: just like ARP/ND suppression 1) Reduce flooding of IGMP messages: just like the ARP/ND suppression
mechanism in EVPN to reduce the flooding of ARP messages over EVPN, mechanism in EVPN to reduce the flooding of ARP messages over EVPN,
it is also desired to have a mechanism to reduce the flood of IGMP it is also desired to have a mechanism to reduce the flooding of IGMP
messages (both Queries and Reports) in EVPN. messages (both Queries and Reports) in EVPN.
2) Distributed anycast multicast proxy: it is desired for the EVPN 2) Distributed anycast multicast proxy: it is desirable for the EVPN
network to act as a distributed anycast multicast router with respect network to act as a distributed anycast multicast router with respect
to IGMP/MLD proxy function for all the hosts attached to that to IGMP/MLD proxy function for all the hosts attached to that
subnet. subnet.
3) Selective Multicast: to forward multicast traffic over EVPN 3) Selective Multicast: to forward multicast traffic over EVPN
network such that it only gets forwarded to the PEs that have network such that it only gets forwarded to the PEs that have
interest in the multicast group(s) - i.e., multicast traffic will not interest in the multicast group(s), multicast traffic will not be
be forwarded to the PEs that have no receivers attached to them for forwarded to the PEs that have no receivers attached to them for that
that multicast group. This draft shows how this objective may be multicast group. This draft shows how this objective may be achieved
achieved when Ingress Replication is used to distribute the multicast when Ingress Replication is used to distribute the multicast traffic
traffic among the PEs. Procedures for supporting selective multicast among the PEs. Procedures for supporting selective multicast using
using P2MP tunnels can be found in [bum-procedure-updates] P2MP tunnels can be found in [bum-procedure-updates]
The first two objectives are achieved by using IGMP/MLD proxy on the The first two objectives are achieved by using IGMP/MLD proxy on the
PE and the third objective is achieved by setting up a multicast PE and the third objective is achieved by setting up a multicast
tunnel (e.g., ingress replication) only among the PEs that have tunnel (e.g., ingress replication) only among the PEs that have
interest in that multicast group(s) based on the trigger from interest in that multicast group(s) based on the trigger from
IGMP/MLD proxy processes. The proposed solutions for each of these IGMP/MLD proxy processes. The proposed solutions for each of these
objectives are discussed in the following sections. objectives are discussed in the following sections.
1.1 Terminology 2 Specification of Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
and "OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in BCP
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3 Terminology
POD: Point of Delivery POD: Point of Delivery
ToR: Top of Rack ToR: Top of Rack
NV: Network Virtualization NV: Network Virtualization
NVO: Network Virtualization Overlay NVO: Network Virtualization Overlay
VNI: Virtual Network Identifier (for VXLAN)
EVPN: Ethernet Virtual Private Network EVPN: Ethernet Virtual Private Network
IGMP: Internet Group Management Protocol IGMP: Internet Group Management Protocol
MLD: Multicast Listener Discovery MLD: Multicast Listener Discovery
EVI: An EVPN instance spanning the Provider Edge (PE) devices EVI: An EVPN instance spanning the Provider Edge (PE) devices
participating in that EVPN participating in that EVPN
MAC-VRF: A Virtual Routing and Forwarding table for Media Access MAC-VRF: A Virtual Routing and Forwarding table for Media Access
Control (MAC) addresses on a PE Control (MAC) addresses on a PE
IR: Ingress Replication
Ethernet Segment (ES): When a customer site (device or network) is Ethernet Segment (ES): When a customer site (device or network) is
connected to one or more PEs via a set of Ethernet links, then that connected to one or more PEs via a set of Ethernet links, then that
set of links is referred to as an 'Ethernet segment'. set of links is referred to as an 'Ethernet Segment'.
Ethernet Segment Identifier (ESI): A unique non-zero identifier that Ethernet Segment Identifier (ESI): A unique non-zero identifier that
identifies an Ethernet segment is called an 'Ethernet Segment identifies an Ethernet Segment is called an 'Ethernet Segment
Identifier'. Identifier'.
PE: Provider Edge device. PE: Provider Edge.
BD: Broadcast Domain. As per [RFC7432], an EVI consists of a single BD: Broadcast Domain. As per [RFC7432], an EVI consists of a single
or multiple BDs. In case of VLAN-bundle and VLAN-based service models or multiple BDs. In case of VLAN-bundle and VLAN-aware bundle service
VLAN-aware bundle service model, an EVI contains multiple BDs. Also, model, an EVI contains multiple BDs. Also, in this document, BD and
in this document, BD and subnet are equivalent terms. subnet are equivalent terms.
Ethernet Tag: An Ethernet tag identifies a particular broadcast Ethernet Tag: An Ethernet tag identifies a particular broadcast
domain, e.g., a VLAN. An EVPN instance consists of one or more domain, e.g., a VLAN. An EVPN instance consists of one or more
broadcast domains. broadcast domains.
Single-Active Redundancy Mode: When only a single PE, among all the Single-Active Redundancy Mode: When only a single PE, among all the
PEs attached to an Ethernet segment, is allowed to forward traffic PEs attached to an Ethernet segment, is allowed to forward traffic
to/from that Ethernet segment for a given VLAN, then the Ethernet to/from that Ethernet segment for a given VLAN, then the Ethernet
segment is defined to be operating in Single-Active redundancy mode. segment is defined to be operating in Single-Active redundancy mode.
All-Active Redundancy Mode: When all PEs attached to an Ethernet All-Active Redundancy Mode: When all PEs attached to an Ethernet
segment are allowed to forward known unicast traffic to/from that segment are allowed to forward known unicast traffic to/from that
Ethernet segment for a given VLAN, then the Ethernet segment is Ethernet segment for a given VLAN, then the Ethernet segment is
defined to be operating in All-Active redundancy mode. defined to be operating in All-Active redundancy mode.
This document also assumes familiarity with the terminology of This document also assumes familiarity with the terminology of
[RFC7432]. Though most of the place this document uses term IGMP [RFC7432]. Though most of the place this document uses term IGMP
membership request (Joins), it MUST be considered true for MLD membership request (Joins), the text applies equally for MLD
membership request too. IGMPv2 corresponds to MLDv1 & IGMPv3 membership request too. Similarly, text for IGMPv2 applies to MLDv1
corresponds to MLDv2. and text for IGMPv3 applies to MLDv2. IGMP / MLD version encoding in
BGP update is stated in section 9
2 IGMP Proxy 4 IGMP/MLD Proxy
IGMP Proxy mechanism is used to reduce the flooding of IGMP messages The IGMP Proxy mechanism is used to reduce the flooding of IGMP
over EVPN network similar to ARP proxy used in reducing the flooding messages over an EVPN network similar to ARP proxy used in reducing
of ARP messages over EVPN. It also provides triggering mechanism for the flooding of ARP messages over EVPN. It also provides a triggering
the PEs to setup their underlay multicast tunnels. IGMP Proxy mechanism for the PEs to setup their underlay multicast tunnels. The
mechanism consist of two components: a) Proxy for IGMP Reports and b) IGMP Proxy mechanism consists of two components: a) Proxy for IGMP
Proxy for IGMP Queries. Reports and b) Proxy for IGMP Queries.
2.1 Proxy Reporting 4.1 Proxy Reporting
When IGMP protocol is used between host/VMs and its first hop EVPN When IGMP protocol is used between hosts/VMs and their first hop EVPN
router (EVPN PE), Proxy-reporting is used by the EVPN PE to summarize router (EVPN PE), Proxy-reporting is used by the EVPN PE to summarize
(when possible) reports received from downstream hosts and propagate (when possible) reports received from downstream hosts and propagate
it in BGP to other PEs that are interested in the information. This them in BGP to other PEs that are interested in the information. This
is done by terminating IGMP Reports in the first hop PE, translating is done by terminating the IGMP Reports in the first hop PE, and
and exchanging the relevant information among EVPN BGP speakers. The translating and exchanging the relevant information among EVPN BGP
information is again translated back to IGMP message at the recipient speakers. The information is again translated back to IGMP message at
EVPN speaker. Thus it helps create an IGMP overlay subnet using BGP. the recipient EVPN speaker. Thus it helps create an IGMP overlay
In order to facilitate such an overlay, this document also defines a subnet using BGP. In order to facilitate such an overlay, this
new EVPN route type NLRI, EVPN Selective Multicast Ethernet Tag document also defines a new EVPN route type NLRI, the EVPN Selective
route, along with its procedures to help exchange and register IGMP Multicast Ethernet Tag route, along with its procedures to help
multicast groups [section 5]. exchange and register IGMP multicast groups [section 7].
2.1.1 IGMP Membership Report Advertisement in BGP 4.1.1 IGMP/MLD Membership Report Advertisement in BGP
When a PE wants to advertise an IGMP membership report (Join) using When a PE wants to advertise an IGMP membership report (Join) using
the BGP EVPN route, it follows the following rules: the BGP EVPN route, it follows the following rules (BGP encoding
stated in section 9.1):
1) When the first hop PE receives several IGMP membership reports 1) When the first hop PE receives several IGMP membership reports
(Joins) , belonging to the same IGMP version, from different attached (Joins), belonging to the same IGMP version, from different attached
hosts/VMs for the same (*,G) or (S,G), it only sends a single BGP hosts/VMs for the same (*,G) or (S,G), it only SHOULD send a single
message corresponding to the very first IGMP Join. This is because BGP message corresponding to the very first IGMP Join (BGP update as
BGP is a statefull protocol and no further transmission of the same soon as possible) for that (*,G) or (S,G). This is because BGP is a
report is needed. If the IGMP Join is for (*,G), then multicast group stateful protocol and no further transmission of the same report is
address along with the corresponding version flag (v2 or v3) are set. needed. If the IGMP Join is for (*,G), then multicast group address
In case of IGMPv3, exclude flag also needs to be set to indicate that MUST be sent along with the corresponding version flag (v2 or v3)
no source IP address to be excluded (e.g., include all sources "*"). set. In case of IGMPv3, the exclude flag MUST also needs to be set to
indicate that no source IP address to be excluded (include all
sources"*").
If the IGMP Join is for (S,G), then besides setting multicast group If the IGMP Join is for (S,G), then besides setting multicast group
address along with the version flag v3, the source IP address and the address along with the version flag v3, the source IP address and the
include/exclude flag must be set. It should be noted that when include/exclude flag MUST be set. It should be noted that when
advertising the EVPN route for (S,G), the only valid version flag is advertising the EVPN route for (S,G), the only valid version flag is
v3 (i.e., v1 and v2 flags must be set to zero). v3 (v1 and v2 flags MUST be set to zero).
2) When the first hop PE receives an IGMPv3 Join for (S,G) on a given 2) When the first hop PE receives an IGMPv3 Join for (S,G) on a given
BD, it advertises the corresponding EVPN Selective Multicast Ethernet BD, it SHOULD advertise the corresponding EVPN Selective Multicast
Tag (SMET) route regardless of whether the source (S) is attached to Ethernet Tag (SMET) route regardless of whether the source (S) is
itself or not in order to facilitate the source move in the future. attached to itself or not in order to facilitate the source move in
the future.
3) When the first hop PE receives an IGMP version-X Join first for 3) When the first hop PE receives an IGMP version-X Join first for
(*,G) and then later it receives an IGMP version-Y Join for the same (*,G) and then later it receives an IGMP version-Y Join for the same
(*,G), then it will re-advertise the same EVPN SMET route with flag (*,G), then it MUST re-advertise the same EVPN SMET route with flag
for version-Y set in addition to any previously-set version flag(s). for version-Y set in addition to any previously-set version flag(s).
In other words, the first hop PE does not withdraw the EVPN route In other words, the first hop PE MUST not withdraw the EVPN route
before sending the new route because the flag field is not part of before sending the new route because the flag field is not part of
BGP route key processing. BGP route key processing.
4) When the first hop PE receives an IGMP version-X Join first for 4) When the first hop PE receives an IGMP version-X Join first for
(*,G) and then later it receives an IGMPv3 Join for the same (*,G) and then later it receives an IGMPv3 Join for the same
multicast group address but for a specific source address S, then the multicast group address but for a specific source address S, then the
PE will advertise a new EVPN SMET route with v3 flag set (and v1 and PE MUST advertise a new EVPN SMET route with v3 flag set (and v1 and
v2 reset). Include/exclude flag also need to be set accordingly. v2 reset). The include/exclude flag also need to be set accordingly.
Since source IP address is used as part of BGP route key processing, Since source IP address is used as part of BGP route key processing,
it is considered as a new BGP route advertisement. it is considered as a new BGP route advertisement.
5) When a PE receives an EVPN SMET route with more than one version 5) When a PE receives an EVPN SMET route with more than one version
flag set, it will generate the corresponding IGMP report for (*,G) flag set, it will generate the corresponding IGMP report for (*,G)
for each version specified in the flag field. With multiple version for each version specified in the flags field. With multiple version
flags set, there MUST not be source IP address in the receive EVPN flags set, there MUST not be source IP address in the receive EVPN
route. If there is, then an error SHOULD be logged. If v3 flag is set route. If there is, then an error SHOULD be logged . If the v3 flag
(in addition to v2), then the include/exclude flag MUST indicate is set (in addition to v2), then the include/exclude flag MUST
"exclude". If not, then an error SHOULD be logged. The PE MUST indicate "exclude". If not, then an error SHOULD be logged. The PE
generate an IGMP membership report (Join) for that (*,G) and each MUST generate an IGMP membership report (Join) for that (*,G) and
IGMP version in the version flag. each IGMP version in the version flag.
6) When a PE receives a list of EVPN SMET NLRIs in its BGP update 6) When a PE receives a list of EVPN SMET NLRIs in its BGP update
message, each with a different source IP address and the same message, each with a different source IP address and the same
multicast group address, and the version flag is set to v3, then the multicast group address, and the version flag is set to v3, then the
PE generates an IGMPv3 membership report with a record corresponding PE generates an IGMPv3 membership report with a record corresponding
to the list of source IP addresses and the group address along with to the list of source IP addresses and the group address along with
the proper indication of inclusion/exclusion. the proper indication of inclusion/exclusion.
7) Upon receiving EVPN SMET route(s) and before generating the 7) Upon receiving EVPN SMET route(s) and before generating the
corresponding IGMP Join(s), the PE checks to see whether it has any corresponding IGMP Join(s), the PE checks to see whether it has any
CE multicast router for that BD on any of its ES's . The PE provides CE multicast router for that BD on any of its ES's . The PE provides
such check by listening for PIM hellos on that AC (i.e, <ES,BD>). If such a check by listening for PIM Hello messages on that AC (i.e,
it has router's ACs, then the generated IGMP Join(s) are sent to <ES,BD>). If the PE does have the router's ACs, then the generated
those ACs. If it doesn't have any router's AC, then no IGMP Join(s) IGMP Join(s) are sent to those ACs. If it doesn't have any of the
needs to be generated because sending IGMP Joins to other hosts can router's AC, then no IGMP Join(s) needs to be generated. This is
result in unintentionally preventing a host from joining a specific because sending IGMP Joins to other hosts can result in
multicast group for IGMPv2 - i.e., if the PE does not receive a join unintentionally preventing a host from joining a specific multicast
from the host it will not forward multicast data to it. Per group using IGMPv2 - i.e., if the PE does not receive a join from the
[RFC4541], when an IGMPv2 host receives a membership report for a host it will not forward multicast data to it. Per [RFC4541], when an
group address that it intends to join, the host will suppress its own IGMPv2 host receives a membership report for a group address that it
membership report for the same group. In other words, an IGMPv2 Join intends to join, the host will suppress its own membership report for
MUST NOT be sent on an AC that does not lead to a CE multicast the same group, and if the PE does not receive an IGMP Join from host
it will not forward multicast data to it. In other words, an IGMPv2
Join MUST NOT be sent on an AC that does not lead to a CE multicast
router. This message suppression is a requirement for IGMPv2 hosts. router. This message suppression is a requirement for IGMPv2 hosts.
This is not a problem for hosts running IGMPv3 because there is no This is not a problem for hosts running IGMPv3 because there is no
suppression of IGMP Membership reports. suppression of IGMP Membership reports.
2.1.1 IGMP Leave Group Advertisement in BGP 4.1.2 IGMP/MLD Leave Group Advertisement in BGP
When a PE wants to withdraw an EVPN SMET route corresponding to an When a PE wants to withdraw an EVPN SMET route corresponding to an
IGMPv2 Leave Group (Leave) or IGMPv3 "Leave" equivalent message, it IGMPv2 Leave Group (Leave) or IGMPv3 "Leave" equivalent message, it
follows the following rules: follows the following rules:
1) When a PE receives an IGMPv2 Leave Group or its "Leave" equivalent 1) When a PE receives an IGMPv2 Leave Group or its "Leave" equivalent
message for IGMPv3 from its attached host, it checks to see if this message for IGMPv3 from its attached host, it checks to see if this
host is the last host who is interested in this multicast group by host is the last host that is interested in this multicast group by
sending a query for the multicast group. If the host was indeed the sending a query for the multicast group. If the host was indeed the
last one, then the PE re-advertises EVPN SMET Multicast route with last one (i.e. no responses are received for the query), then the PE
the corresponding version flag reset. If this is the last version MUST re-advertises EVPN SMET Multicast route with the corresponding
flag to be reset, then instead of re-advertising the EVPN route with version flag reset. If this is the last version flag to be reset,
all version flags reset, the PE withdraws the EVPN route for that then instead of re-advertising the EVPN route with all version flags
(*,G). reset, the PE MUST withdraws the EVPN route for that (*,G).
2) When a PE receives an EVPN SMET route for a given (*,G), it 2) When a PE receives an EVPN SMET route for a given (*,G), it
compares the received version flags from the route with its per-PE compares the received version flags from the route with its per-PE
stored version flags. If the PE finds that a version flag associated stored version flags. If the PE finds that a version flag associated
with the (*,G) for the remote PE is reset, then the PE generates IGMP with the (*,G) for the remote PE is reset, then the PE MUST generate
Leave for that (*,G) toward its local interface (if any) attached to IGMP Leave for that (*,G) toward its local interface (if any)
the multicast router for that multicast group. It should be noted attached to the multicast router for that multicast group. It should
that the received EVPN route should at least have one version flag be noted that the received EVPN route SHOULD at least have one
set. If all version flags are reset, it is an error because the PE version flag set. If all version flags are reset, it is an error
should have received an EVPN route withdraw for the last version because the PE should have received an EVPN route withdraw for the
flag. If the PE receives an EVPN SMET route withdraw, then it must last version flag. Error MUST be considered as BGP error and SHOULD
remove the remote PE from the OIF list associated with that multicast be handled as per [RFC7606].
group.
3) When a PE receives an EVPN SMET route withdraw, it removes the 3) When a PE receives an EVPN SMET route withdraw, it removes the
remote PE from its OIF list for that multicast group and if there are remote PE from its OIF list for that multicast group and if there are
no more OIF entries for that multicast group (either locally or no more OIF entries for that multicast group (either locally or
remotely), then the PE MUST stop responding to queries from the remotely), then the PE MUST stop responding to queries from the
locally attached router (if any). If there is a source for that locally attached router (if any). If there is a source for that
multicast group, the PE stops sending multicast traffic for that multicast group, the PE stops sending multicast traffic for that
source. source.
2.2 Proxy Querier 4.2 Proxy Querier
As mentioned in the previous sections, each PE need to have proxy As mentioned in the previous sections, each PE MUST have proxy
querier functionality for the following reasons: querier functionality for the following reasons:
1) To enable the collection of EVPN PEs providing L2VPN service to 1) To enable the collection of EVPN PEs providing L2VPN service to
act as distributed multicast router with Anycast IP address for all act as distributed multicast router with Anycast IP address for all
attached hosts/VMs in that subnet. attached hosts/VMs in that subnet.
2) To enable suppression of IGMP membership reports and queries over 2) To enable suppression of IGMP membership reports and queries over
MPLS/IP core. MPLS/IP core.
3 Operation 5 Operation
Consider the EVPN network of figure-1, where there is an EVPN Consider the EVPN network of Figure-1, where there is an EVPN
instance configured across the PEs shown in this figure (namely PE1, instance configured across the PEs shown in this figure (namely PE1,
PE2, and PE3). Lets consider that this EVPN instance consist of a PE2, and PE3). Let's consider that this EVPN instance consists of a
single bridge domain (single subnet) with all the hosts, sources and single bridge domain (single subnet) with all the hosts, sources, and
the multicast router shown in this figure connected to this subnet. the multicast router connected to this subnet. PE1 only has hosts
PE1 only has hosts connected to it. PE2 has a mix of hosts and connected to it. PE2 has a mix of hosts and a multicast source. PE3
multicast source. PE3 has a mix of hosts, multicast source, and has a mix of hosts, a multicast source, and a multicast router.
multicast router. Further more, lets consider that for (S1,G1), R1 is Furthermore, let's consider that for (S1,G1), R1 is used as the
used as the multicast router. The following subsections describe the multicast router. The following subsections describe the IGMP proxy
IGMP proxy operation in different PEs with regard to whether the operation in different PEs with regard to whether the locally
locally attached devices for that subnet are: attached devices for that subnet are:
- only hosts/VMs - only hosts/VMs
- mix of hosts/VMs and multicast source - mix of hosts/VMs and multicast source
- mix of hosts/VMs, multicast source, and multicast router - mix of hosts/VMs, multicast source, and multicast router
+--------------+ +--------------+
| | | |
| | | |
+----+ | | +----+ +----+ | | +----+
H1:(*,G1)v2 ---| | | | | |---- H6(*,G1)v2 H1:(*,G1)v2 ---| | | | | |---- H6(*,G1)v2
skipping to change at page 10, line 25 skipping to change at page 10, line 34
+----+ | | +----+ +----+ | | +----+
| | | |
+----+ | | +----+ | |
H5:(S1,G1)v3 --| | | | H5:(S1,G1)v3 --| | | |
S1 ---| PE3| | | S1 ---| PE3| | |
R1 ---| | | | R1 ---| | | |
+----+ | | +----+ | |
| | | |
+--------------+ +--------------+
Figure 1: Figure 1: EVPN network
3.1 PE with only attached hosts/VMs for a given subnet 5.1 PE with only attached hosts/VMs for a given subnet
When PE1 receives an IGMPv2 Join Report from H1, it does not forward When PE1 receives an IGMPv2 Join Report from H1, it does not forward
this join to any of its other ports (for this subnet) because all this join to any of its other ports (for this subnet) because all
these local ports are associated with the hosts/VMs. PE1 sends an these local ports are associated with the hosts/VMs. PE1 sends an
EVPN Multicast Group route corresponding to this join for (*,G1) and EVPN Multicast Group route corresponding to this join for (*,G1) and
setting v2 flag. This EVPN route is received by PE2 and PE3 that are setting v2 flag. This EVPN route is received by PE2 and PE3 that are
the member of the same BD (i.e., same EVI in case of VLAN-based the members of the same BD (i.e., same EVI in case of VLAN-based
service or <EVI,VLAN> in case of VLAN-aware bundle service). PE3 service or <EVI,VLAN> in case of VLAN-aware bundle service). PE3
reconstructs IGMPv2 Join Report from this EVPN BGP route and only reconstructs the IGMPv2 Join Report from this EVPN BGP route and only
sends it to the port(s) with multicast routers attached to it (for sends it to the port(s) with multicast routers attached to it (for
that subnet). In this example, PE3 sends the reconstructed IGMPv2 that subnet). In this example, PE3 sends the reconstructed IGMPv2
Join Report for (*,G1) to only R1. Furthermore, PE2 although receives Join Report for (*,G1) only to R1. Furthermore, even though PE2
the EVPN BGP route, it does not send it to any of its port for that receives the EVPN BGP route, it does not send it to any of its ports
subnet - namely ports associated with H6 and H7. for that subnet; viz, ports associated with H6 and H7.
When PE1 receives the second IGMPv2 Join from H2 for the same When PE1 receives the second IGMPv2 Join from H2 for the same
multicast group (*,G1), it only adds that port to its OIF list but it multicast group (*,G1), it only adds that port to its OIF list but it
doesn't send any EVPN BGP route because there is no change in doesn't send any EVPN BGP route because there is no change in
information. However, when it receives the IGMPv3 Join from H3 for information. However, when it receives the IGMPv3 Join from H3 for
the same (*,G1), besides adding the corresponding port to its OIF the same (*,G1). Besides adding the corresponding port to its OIF
list, it re-advertises the previously sent EVPN SMET route with the list, it re-advertises the previously sent EVPN SMET route with the
version-3 & exclude flag set. v3 & exclude flag set.
Finally when PE1 receives the IMGMPv3 Join from H4 for (S2,G2), it Finally when PE1 receives the IMGMPv3 Join from H4 for (S2,G2), it
advertises a new EVPN SMET route corresponding to it. advertises a new EVPN SMET route corresponding to it.
3.2 PE with mixed of attached hosts/VMs and multicast source 5.2 PE with a mix of attached hosts/VMs and multicast source
The main difference in here is that when PE2 receives IGMPv3 Join The main difference in this case is that when PE2 receives the IGMPv3
from H7 for (S2,G2), it does advertises it in BGP to support source Join from H7 for (S2,G2), it does advertise it in BGP to support
move even though PE2 knows that S2 is attached to its local AC. PE2 source move even though PE2 knows that S2 is attached to its local
adds the port associated with H7 to its OIF list for (S2,G2). The AC. PE2 adds the port associated with H7 to its OIF list for (S2,G2).
processing for IGMPv2 received from H6 is the same as the v2 Join The processing for IGMPv2 received from H6 is the same as the IGMPv2
described in previous section. Join described in previous section.
3.3 PE with mixed of attached hosts/VMs, multicast source and router 5.3 PE with a mix of attached hosts/VMs, a multicast source and a router
The main difference in here relative to the previous two sections is The main difference in this case relative to the previous two
that Join messages received locally needs to be sent to the port sections is that IGMP v2/v3 Join messages received locally needs to
associated with router R1. Furthermore, the Joins received via BGP be sent to the port associated with router R1. Furthermore, the Joins
need to be passed to the R1 port but filtered for all other ports. received via BGP (SMET) need to be passed to the R1 port but filtered
for all other ports.
4 All-Active Multi-Homing 6 All-Active Multi-Homing
Because a CE's LAG flow hashing algorithm is unknown, in an All- Because the LAG flow hashing algorithm used by the CE is unknown at
Active redundancy mode it must be assumed that the CE can send a the PE, in an All-Active redundancy mode it must be assumed that the
given IGMP message to any one of the multi-homed PEs, either DF or CE can send a given IGMP message to any one of the multi-homed PEs,
non-DF - i.e., different IGMP Join messages can arrive at different either DF or non-DF; i.e., different IGMP Join messages can arrive at
PEs in the redundancy group and furthermore their corresponding Leave different PEs in the redundancy group and furthermore their
messages can arrive at PEs that are different from the ones received corresponding Leave messages can arrive at PEs that are different
the Join messages. Therefore, all PEs attached to a given ES must from the ones that received the Join messages. Therefore, all PEs
coordinate IGMP Join and Leave Group (x, G) state, where x may be attached to a given ES must coordinate IGMP Join and Leave Group
either '*' or a particular source S, for each BD on that ES. This (x,G) state, where x may be either '*' or a particular source S, for
allows the DF for that [ES, BD] to correctly advertise or withdraw a each BD on that ES. This allows the DF for that [ES,BD] to correctly
Selective Multicast Ethernet Tag (SMET) route for that (x, G) group advertise or withdraw a Selective Multicast Ethernet Tag (SMET) route
in that BD when needed. for that (x,G) group in that BD when needed.
All-Active multihoming PEs for a given ES MUST support IGMP synch All-Active multihoming PEs for a given ES MUST support IGMP
procedures described in this section if they want to perform IGMP synchronization procedures described in this section if they need to
proxy for hosts connects to that ES. perform IGMP proxy for hosts connected to that ES.
4.1 Local IGMP Join Synchronization 6.1 Local IGMP/MLD Join Synchronization
When a PE, either DF or non-DF, receives, on a given multihomed ES When a PE, either DF or non-DF, receives on a given multihomed ES
operating in All-Active redundancy mode, an IGMP Membership Report operating in All-Active redundancy mode, an IGMP Membership Report
for (x, G), it determines the BD to which the IGMP Membership Report for (x,G), it determines the BD to which the IGMP Membership Report
belongs. If the PE doesn't already have local IGMP Join (x, G) state belongs. If the PE doesn't already have local IGMP Join (x,G) state
for that BD on that ES, it instantiates local IGMP Join (x, G) state for that BD on that ES, it MUST instantiate local IGMP Join (x,G)
and advertises a BGP IGMP Join Synch route for that [ES, BD]. Local state and MUST advertise a BGP IGMP Join Synch route for that [ES,
IGMP Join (x, G) state refers to IGMP Join (x, G) state that is BD]. Local IGMP Join (x, G) state refers to IGMP Join (x,G) state
created as the result of processing an IGMP Membership Report for (x, that is created as a result of processing an IGMP Membership Report
G). for (x,G).
The IGMP Join Synch route carries the ES-Import RT for the ES on The IGMP Join Synch route MUST carry the ES-Import RT for the ES on
which the IGMP Membership Report was received. Thus it may only go which the IGMP Membership Report was received. Thus it MUST only be
to the PEs attached to that ES (and not any other PEs). sent to the PEs attached to that ES and not any other PEs.
When a PE, either DF or non-DF, receives an IGMP Join Synch route it When a PE, either DF or non-DF, receives an IGMP Join Synch route it
installs that route and if it doesn't already have IGMP Join (x, G) installs that route and if it doesn't already have IGMP Join (x,G)
state for that [ES, BD], it instantiates that IGMP Join (x,G) state - state for that [ES,BD], it MUST instantiate that IGMP Join (x,G)
i.e., IGMP Join (x, G) state is the union of local IGMP Join (x, G) state - i.e., IGMP Join (x,G) state is the union of the local IGMP
state and installed IGMP Join Synch route. If the DF is not currently Join (x,G) state and the installed IGMP Join Synch route. If the DF
advertising (originating) a SMET route for that (x, G) group in that did not already advertise (originate) a SMET route for that (x,G)
BD, it does so now. group in that BD, it MUST do so now.
When a PE, either DF or non-DF, deletes its local IGMP Join (x, G) When a PE, either DF or non-DF, deletes its local IGMP Join (x, G)
state for that [ES, BD], it withdraws its BGP IGMP Join Synch route state for that [ES,BD], it MUST withdraw its BGP IGMP Join Synch
for that [ES, BD]. route for that [ES,BD].
When a PE, either DF or non-DF, receives the withdrawal of an IGMP When a PE, either DF or non-DF, receives the withdrawal of an IGMP
Join Synch route from another PE it removes that route. When a PE Join Synch route from another PE it MUST remove that route. When a
has no local IGMP Join (x, G) state and it has no installed IGMP Join PE has no local IGMP Join (x,G) state and it has no installed IGMP
Synch routes, it removes IGMP Join (x, G) state for that [ES, BD]. Join Synch routes, it MUST remove IGMP Join (x,G) state for that [ES,
If the DF no longer has IGMP Join (x, G) state for that BD on any ES BD]. If the DF no longer has IGMP Join (x,G) state for that BD on
for which it is DF, it withdraws its SMET route for that (x, G) group any ES for which it is DF, it MUST withdraw its SMET route for that
in that BD. (x,G) group in that BD.
I.e., A PE advertises an SMET route for that (x, G) group in that BD
when it has IGMP Join (x, G) state in that BD on at least one ES for
which it is DF and it withdraws that SMET route when it does not have
IGMP Join (x, G) state in that BD on any ES for which it is DF.
4.2 Local IGMP Leave Group Synchronization In other words, a PE advertises an SMET route for that (x,G) group in
that BD when it has IGMP Join (x,G) state in that BD on at least one
ES for which it is DF and it withdraws that SMET route when it does
not have IGMP Join (x,G) state in that BD on any ES for which it is
DF.
6.2 Local IGMP/MLD Leave Group Synchronization
When a PE, either DF or non-DF, receives, on a given multihomed ES When a PE, either DF or non-DF, receives, on a given multihomed ES
operating in All-Active redundancy mode, an IGMP Leave Group message operating in All-Active redundancy mode, an IGMP Leave Group message
for (x, G) from the attached CE, it determines the BD to which the for (x,G) from the attached CE, it determines the BD to which the
IGMPv2 Leave Group belongs. Regardless of whether it has IGMP Join IGMPv2 Leave Group belongs. Regardless of whether it has IGMP Join
(x, G) state for that [ES, BD], it initiates the (x, G) leave group (x,G) state for that [ES,BD], it initiates the (x,G) leave group
synchronization procedure, which consists of the following steps: synchronization procedure, which consists of the following steps:
1) It computes the Maximum Response Time, which is the duration of 1) It computes the Maximum Response Time, which is the duration of
(x, G) leave group synchronization procedure. This is the product of (x,G) leave group synchronization procedure. This is the product of
two locally configured values, Last Member Query Count and Last two locally configured values, Last Member Query Count and Last
Member Query Interval (described in Section 3 of [RFC2236]), plus Member Query Interval (described in Section 3 of [RFC2236]), plus a
delta, the time it takes for a BGP advertisement to propagate between delta corresponding to the time it takes for a BGP advertisement to
the PEs attached to the multihomed ES (delta is a consistently propagate between the PEs attached to the multihomed ES (delta is a
configured value on all PEs attached to the multihomed ES). consistently configured value on all PEs attached to the multihomed
ES).
2) It starts the Maximum Response Time timer. Note that the receipt 2) It starts the Maximum Response Time timer. Note that the receipt
of subsequent IGMP Leave Group messages or BGP Leave Synch routes for of subsequent IGMP Leave Group messages or BGP Leave Synch routes for
(x, G) do not change the value of a currently running Maximum (x,G) do not change the value of a currently running Maximum Response
Response Time timer and are ignored by the PE. Time timer and are ignored by the PE.
3) It initiates the Last Member Query procedure described in Section 3) It initiates the Last Member Query procedure described in Section
3 of [RFC2236]; viz, it sends a number of Group-Specific Query (x, G) 3 of [RFC2236]; viz, it sends a number of Group-Specific Query (x,G)
messages (Last Member Query Count) at a fixed interval (Last Member messages (Last Member Query Count) at a fixed interval (Last Member
Query Interval) to the attached CE. Query Interval) to the attached CE.
4) It advertises an IGMP Leave Synch route for that that [ES, BD]. 4) It advertises an IGMP Leave Synch route for that that [ES,BD].
This route notifies the other multihomed PEs attached to the given This route notifies the other multihomed PEs attached to the given
multihomed ES that it has initiated an (x, G) leave group multihomed ES that it has initiated an (x,G) leave group
synchronization procedure; i.e., it carries the ES-Import RT for the synchronization procedure; i.e., it carries the ES-Import RT for the
ES on which the IGMP Leave Group was received. It also contains the ES on which the IGMP Leave Group was received. It also contains the
Maximum Response Time and the Leave Group Synchronization Procedure Maximum Response Time and the Leave Group Synchronization Procedure
Sequence number. The latter identifies the specific (x, G) leave Sequence number. The latter identifies the specific (x,G) leave group
group synchronization procedure initiated by the advertising PE, synchronization procedure initiated by the advertising PE, which
which increments the value whenever it initiates a procedure. increments the value whenever it initiates a procedure.
5) When the Maximum Response Timer expires, the PE that has 5) When the Maximum Response Timer expires, the PE that has
advertised the IGMP Leave Synch route withdraws it. advertised the IGMP Leave Synch route withdraws it.
4.2.1 Remote Leave Group Synchronization 6.2.1 Remote Leave Group Synchronization
When a PE, either DF or non-DF, receives an IGMP Leave Synch route it When a PE, either DF or non-DF, receives an IGMP Leave Synch route it
installs that route and it starts a timer for (x, G) on the specified installs that route and it starts a timer for (x,G) on the specified
[ES, BD] whose value is set to the Maximum Response Time in the [ES,BD] whose value is set to the Maximum Response Time in the
received IGMP Leave Synch route. Note that the receipt of subsequent received IGMP Leave Synch route. Note that the receipt of subsequent
IGMPv2 Leave Group messages or BGP Leave Synch routes for (x, G) do IGMPv2 Leave Group messages or BGP Leave Synch routes for (x,G) do
not change the value of a currently running Maximum Response Time not change the value of a currently running Maximum Response Time
timer and are ignored by the PE. timer and are ignored by the PE.
4.2.2 Common Leave Group Synchronization 6.2.2 Common Leave Group Synchronization
If a PE attached to the multihomed ES receives an IGMP Membership If a PE attached to the multihomed ES receives an IGMP Membership
Report for (x, G) before the Maximum Response Time timer expires, it Report for (x,G) before the Maximum Response Time timer expires, it
advertises a BGP IGMP Join Synch route for that [ES, BD]. If it advertises a BGP IGMP Join Synch route for that [ES,BD]. If it
doesn't already have local IGMP Join (x, G) state for that [ES, BD], doesn't already have local IGMP Join (x, G) state for that [ES, BD],
it instantiates local IGMP Join (x, G) state. If the DF is not it instantiates local IGMP Join (x,G) state. If the DF is not
currently advertising (originating) a SMET route for that (x, G) currently advertising (originating) a SMET route for that (x,G) group
group in that BD, it does so now. in that BD, it does so now.
If a PE attached to the multihomed ES receives an IGMP Join Synch If a PE attached to the multihomed ES receives an IGMP Join Synch
route for (x, G) before the Maximum Response Time timer expires, it route for (x,G) before the Maximum Response Time timer expires, it
installs that route and if it doesn't already have IGMP Join (x, G) installs that route and if it doesn't already have IGMP Join (x,G)
state for that BD on that ES, it instantiates that IGMP Join (x,G) state for that BD on that ES, it instantiates that IGMP Join (x,G)
state. If the DF is not currently advertising (originating) a SMET state. If the DF has not already advertised (originated) a SMET route
route for that (x, G) group in that BD, it does so now. for that (x,G) group in that BD, it does so now.
When the Maximum Response Timer expires a PE that has advertised an When the Maximum Response Timer expires a PE that has advertised an
IGMP Leave Synch route, withdraws it. Any PE attached to the IGMP Leave Synch route, withdraws it. Any PE attached to the
multihomed ES, that started the Maximum Response Time and has no multihomed ES, that started the Maximum Response Time and has no
local IGMP Join (x, G) state and no installed IGMP Join Synch routes, local IGMP Join (x,G) state and no installed IGMP Join Synch routes,
it removes IGMP Join (x, G) state for that [ES, BD]. If the DF no it removes IGMP Join (x,G) state for that [ES,BD]. If the DF no
longer has IGMP Join (x, G) state for that BD on any ES for which it longer has IGMP Join (x,G) state for that BD on any ES for which it
is DF, it withdraws its SMET route for that (x, G) group in that BD. is DF, it withdraws its SMET route for that (x,G) group in that BD.
4.3 Mass Withdraw of Multicast join Sync route in case of failure 6.3 Mass Withdraw of Multicast join Sync route in case of failure
A PE which has received IGMP join, would have synced IGMP join by A PE which has received an IGMP Join, would have synced the IGMP Join
procedure section(4.1). If PE with local join state goes down or PE by the procedure defined in section 6.1. If a PE with local join
to CE link goes down, it would lead to mass withdraw of multicast state goes down or the PE to CE link goes down, it would lead to a
routes. Remote PE (PE where these routes were remote IGMP join) mass withdraw of multicast routes. Remote PEs (PEs where these routes
SHOULD not remove the state immediately where as General Query SHOULD were remote IGMP Joins) SHOULD not remove the state immediately;
be generated to refresh the states. Some of the way (But not limited instead General Query SHOULD be generated to refresh the states.
to) to detect failure at peer could be IGP next hop tracking or ES There are several ways to Some of the way to detect failure at a
route withdraw. peer, e.g. using IGP next hop tracking or ES route withdraw.
5 Single-Active Multi-Homing 7 Single-Active Multi-Homing
Note that to facilitate state synchronization after failover, the PEs Note that to facilitate state synchronization after failover, the PEs
attached to a mutihomed ES operating in Single-Active redundancy mode attached to a mutihomed ES operating in Single-Active redundancy mode
should also coordinate IGMP Join (x, G) state. In this case all IGMP SHOULD also coordinate IGMP Join (x,G) state. In this case all IGMP
Join messages are received by the DF and distributed to the non-DF Join messages are received by the DF and distributed to the non-DF
PEs using the procedures described above. PEs using the procedures described above.
6 Selective Multicast Procedures for IR tunnels 8 Selective Multicast Procedures for IR tunnels
If an ingress PE uses ingress replication, then for a given (x,G)
If an ingress PE uses ingress replication, then for a given (x, G)
group in a given BD: group in a given BD:
1) It sends (x, G) traffic to the set of PEs not supporting IGMP 1) It sends (x,G) traffic to the set of PEs not supporting IGMP
Proxy. This set consists of any PE that has advertised an Inclusive Proxy. This set consists of any PE that has advertised an Inclusive
Multicast Tag route for the BD without the "IGMP Proxy Support" flag. Multicast Tag route for the BD without the "IGMP Proxy Support" flag.
2) It sends (x, G) traffic to the set of PEs supporting IGMP Proxy 2) It sends (x,G) traffic to the set of PEs supporting IGMP Proxy
and having listeners for that (x, G) group in that BD. This set and having listeners for that (x,G) group in that BD. This set
consists of any PE that has advertised an Inclusive Multicast Tag consists of any PE that has advertised an Inclusive Multicast Tag
route for the BD with the "IGMP Proxy Support" flag and that has route for the BD with the "IGMP Proxy Support" flag and that has
advertised an SMET route for that (x, G) group in that BD. advertised a SMET route for that (x,G) group in that BD.
If an ingress PE's Selective P-Tunnel for a given BD uses P2MP and If an ingress PE's Selective P-Tunnel for a given BD uses P2MP and
all of the PEs in the BD support that tunnel type and IGMP, then for all of the PEs in the BD support that tunnel type and IGMP proxy,
a given (x, G) group in a given BD it sends (x, G) traffic using the then for a given (x,G) group in a given BD it sends (x,G) traffic
Selective P-Tunnel for that (x, G) group in that BD. This tunnel using the Selective P-Tunnel for that (x,G) group in that BD. This
will include those PEs that have advertised an SMET route for that tunnel includes those PEs that have advertised a SMET route for that
(x, G) group on that BD (for Selective P-tunnel) but it may include (x,G) group on that BD (for Selective P-tunnel) but it may include
other PEs as well (for Aggregate Selective P-tunnel). other PEs as well (for Aggregate Selective P-tunnel).
7 BGP Encoding 9 BGP Encoding
This document defines three new BGP EVPN routes to carry IGMP This document defines three new BGP EVPN routes to carry IGMP
membership reports. This route type is known as: membership reports. The route type is known as:
+ 6 - Selective Multicast Ethernet Tag Route + 6 - Selective Multicast Ethernet Tag Route
+ 7 - Multicast Join Synch Route + 7 - Multicast Join Synch Route
+ 8 - Multicast Leave Synch Route + 8 - Multicast Leave Synch Route
The detailed encoding and procedures for this route type is described The detailed encoding and procedures for this route type are
in subsequent section. described in subsequent sections.
7.1 Selective Multicast Ethernet Tag Route 9.1 Selective Multicast Ethernet Tag Route
An Selective Multicast Ethernet Tag route type specific EVPN NLRI A Selective Multicast Ethernet Tag route type specific EVPN NLRI
consists of the following: consists of the following:
+---------------------------------------+ +---------------------------------------+
| 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 Address (variable) | | Multicast Source Address (variable) |
+---------------------------------------+ +---------------------------------------+
| Multicast Group Length (1 octet) | | Multicast Group Length (1 octet) |
+---------------------------------------+ +---------------------------------------+
| Multicast Group Address (Variable) | | Multicast Group Address (Variable) |
+---------------------------------------+ +---------------------------------------+
| Originator Router Length (1 octet) | | Originator Router Length (1 octet) |
+---------------------------------------+ +---------------------------------------+
| Originator Router Address (variable) | | Originator Router Address (variable) |
+---------------------------------------+ +---------------------------------------+
| Flags (1 octets) (optional) | | Flags (1 octet) |
+---------------------------------------+ +---------------------------------------+
For the purpose of BGP route key processing, all the fields are For the purpose of BGP route key processing, all the fields are
considered to be part of the prefix in the NLRI except for the one- considered to be part of the prefix in the NLRI except for the one-
octet optional flag field (if included). The Flags fields are defined octet flag field. The Flags fields are defined as follows:
as follows:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
| reserved |IE|v3|v2|v1| | reserved |IE|v3|v2|v1|
+--+--+--+--+--+--+--+--+ +--+--+--+--+--+--+--+--+
The least significant bit, bit 7 indicates support for IGMP version The least significant bit, bit 7 indicates support for IGMP version
1. 1.
The second least significant bit, bit 6 indicates support for IGMP The second least significant bit, bit 6 indicates support for IGMP
version 2. version 2.
The third least significant bit, bit 5 indicates support for IGMP The third least significant bit, bit 5 indicates support for IGMP
version 3. version 3.
The forth least significant bit, bit 4 indicates whether the (S, G) The forth least significant bit, bit 4 indicates whether the (S,G)
information carried within the route-type is of Include Group type information carried within the route-type is of an Include Group type
(bit value 0) or an Exclude Group type (bit value 1). The Exclude (bit value 0) or an Exclude Group type (bit value 1). The Exclude
Group type bit MUST be ignored if bit 5 is not set. Group type bit MUST be ignored if bit 5 is not set.
This EVPN route type is used to carry tenant IGMP multicast group This EVPN route type is used to carry tenant IGMP multicast group
information. The flag field assists in distributing IGMP membership information. The flag field assists in distributing IGMP membership
interest of a given host/VM for a given multicast route. The version interest of a given host/VM for a given multicast route. The version
bits help associate IGMP version of receivers participating within bits help associate IGMP version of receivers participating within
the EVPN domain. the EVPN domain.
The include/exclude bit helps in creating filters for a given The include/exclude bit helps in creating filters for a given
multicast route. multicast route.
If route is being prepared for IPv6 (MLD) then bit 7 indicates If route is used for IPv6 (MLD) then bit 7 indicates support for MLD
support for MLD version 1. The second least significant bit, bit 6 version 1. The second least significant bit, bit 6 indicates support
indicates support for MLD version 2. Since there is no MLD version 3, for MLD version 2. Since there is no MLD version 3, in case of IPv6
in case of IPv6 route third least significant bit MUST be 0. In case route third least significant bit MUST be 0. In case of IPv6 routes,
of IPv6 route, the fourth least significant bit MUST be ignored if the fourth least significant bit MUST be ignored if bit 6 is not
bit 6 is not set. set.
7.1.1 Constructing the Selective Multicast Ethernet Tag route 9.1.1 Constructing the Selective Multicast Ethernet Tag route
This section describes the procedures used to construct the Selective This section describes the procedures used to construct the Selective
Multicast Ethernet Tag (SMET) route. Support for this route type is Multicast Ethernet Tag (SMET) route.
optional.
The Route Distinguisher (RD) SHOULD be a Type 1 RD [RFC4364]. The The Route Distinguisher (RD) SHOULD be a Type 1 RD [RFC4364]. The
value field comprises an IP address of the PE (typically, the value field comprises an IP address of the PE (typically, the
loopback address) followed by a number unique to the PE. loopback address) followed by a number unique to the PE.
The Ethernet Tag ID MUST be set as follows: The Ethernet Tag ID MUST be set as follows:
EVI is VLAN-Based or VLAN Bundle service - set to 0 EVI is VLAN-Based or VLAN Bundle service - set to 0
EVI is VLAN-Aware Bundle service without translation - set to EVI is VLAN-Aware Bundle service without translation - set to
the customer VID for that BD the customer VID for that BD
EVI is VLAN-Aware Bundle service with translation - set to the EVI is VLAN-Aware Bundle service with translation - set to the
normalized Ethernet Tag ID - e.g., normalized VID normalized Ethernet Tag ID - e.g., normalized VID
The Multicast Source length MUST be set to length of Multicast Source The Multicast Source Length MUST be set to length of the multicast
address in bits. If the Multicast Source field contains an IPv4 Source address in bits. If the Multicast Source Address field
address, then the value of the Multicast Source Length field is 32. contains an IPv4 address, then the value of the Multicast Source
If the Multicast Source field contains an IPv6 address, then the Length field is 32. If the Multicast Source Address field contains an
value of the Multicast Source Length field is 128. In case of a (*, IPv6 address, then the value of the Multicast Source Length field is
G) Join, the Multicast Source Length is set to 0. 128. In case of a (*, G) Join, the Multicast Source Length is set to
0.
The Multicast Source is the Source IP address of the IGMP membership The Multicast Source Address is the source IP address from the IGMP
report. In case of a (*, G) Join, this field does not exist. membership report. In case of a (*, G), this field is not used.
The Multicast Group length MUST be set to length of multicast group The Multicast Group Length MUST be set to length of multicast group
address in bits. If the Multicast Group field contains an IPv4 address in bits. If the Multicast Group Address field contains an
address, then the value of the Multicast Group Length field is 32. IPv4 address, then the value of the Multicast Group Length field is
If the Multicast Group field contains an IPv6 address, then the value 32. If the Multicast Group Address field contains an IPv6 address,
of the Multicast Group Length field is 128. then the value of the Multicast Group Length field is 128.
The Multicast Group is the Group address of the IGMP membership The Multicast Group Address is the Group address from the IGMP
report. membership report.
The Originator Router Length is the length of the Originator Router The Originator Router Length is the length of the Originator Router
address in bits. Address in bits.
The Originator Router Address is the IP address of Router Originating The Originator Router Address is the IP address of router originating
the prefix. It should be noted that using the "Originating Router's the prefix. It should be noted that using the "Originating Router's
IP address" field is needed for local-bias procedures and may be IP address" field is needed for local-bias procedures and may be
needed for building inter-AS multicast underlay tunnels where BGP needed for building inter-AS multicast underlay tunnels where the BGP
next hop can get over written. next-hop can get overwritten.
The Flags field indicates the version of IGMP protocol from which the The Flags field indicates the version of IGMP protocol from which the
membership report was received. It also indicates whether the membership report was received. It also indicates whether the
multicast group had INCLUDE or EXCLUDE bit set. multicast group had the INCLUDE or EXCLUDE bit set.
IGMP protocol is used to receive group membership information from IGMP is used to receive group membership information from hosts/VMs
hosts/VMs by TORs. Upon receiving the hosts/VMs expression of by TORs. Upon receiving the hosts/VMs expression of interest of a
interest of a particular group membership, this information is then particular group membership, this information is then forwarded using
forwarded using Ethernet Multicast Source Group Route NLRI. The NLRI Ethernet Multicast Source Group Route NLRI. The NLRI also keeps track
also keeps track of receiver's IGMP protocol version and any "source of receiver's IGMP protocol version and any source filtering for a
filtering" for a given group membership. All EVPN SMET routes are given group membership. All EVPN SMET routes are announced with per-
announced with per-EVI Route Target extended communities. EVI Route Target extended communities.
7.1.2 Default Selective Multicast Route 9.1.2 Default Selective Multicast Route
If there is multicast router connected behind the EVPN domain, the PE
MAY originate a default SMET (*,*) to get all multicast traffic in
domain.
If there is multicast router connected behind EVPN domain, PE MAY
originate default SMET (*,*) to get all multicast traffic in domain.
For example,
+--------------+ +--------------+
| | | |
| | | |
| | +----+ | | +----+
| | | |---- H1(*,G1)v2 | | | |---- H1(*,G1)v2
| IP/MPLS | | PE1|---- H2(S2,G2)v3 | IP/MPLS | | PE1|---- H2(S2,G2)v3
| Network | | |---- S2 | Network | | |---- S2
| | | | | | | |
| | +----+ | | +----+
| | | |
+----+ | | +----+ | |
+----+ | | | | +----+ | | | |
| | S1 ---| PE2| | | | | S1 ---| PE2| | |
|PIM |----R1 ---| | | | |PIM |----R1 ---| | | |
|ASM | +----+ | | |ASM | +----+ | |
| | | | | | | |
+----+ +--------------+ +----+ +--------------+
Figure 2: Figure 2: Multicast Router behind EVPN domain
Consider the EVPN network of figure-2, where there is an EVPN Consider the EVPN network of Figure-2, where there is an EVPN
instance configured across the PEs shows in this figure. Lets instance configured across the PEs. Lets consider PE2 is connected to
consider PE2 is connected to multicast router R1 and there is PIM ASM multicast router R1 and there is a network running PIM ASM behind R1.
network behind R1. If there are receivers behind PIM ASM network, PIM If there are receivers behind the PIM ASM network, the PIM Join would
join would be forwarded to PIM RP (Rendezvous Point). If receivers be forwarded to the PIM RP (Rendezvous Point). If receivers behind
behind PIM ASM network are interested in multicast flow originated by PIM ASM network are interested in a multicast flow originated by
multicast source S2 (Behind PE1), it is necessary for PE2 to receive multicast source S2 (behind PE1), it is necessary for PE2 to receive
multicast traffic. In this case PE2 MUST originate (*,*) SMET route multicast traffic. In this case PE2 MUST originate a (*,*) SMET route
to receive all of the multicast traffic in EVPN domain. to receive all of the multicast traffic in the EVPN domain.
7.2 Multicast Join Synch Route 9.2 Multicast Join Synch Route
This EVPN route type is used to coordinate IGMP Join (x,G) state for This EVPN route type is used to coordinate IGMP Join (x,G) state for
a given BD between the PEs attached to a given ES operating in All- a given BD between the PEs attached to a given ES operating in All-
Active (or Single-Active) redundancy mode and it consists of Active (or Single-Active) redundancy mode and it consists of
following: following:
+--------------------------------------------------+ +--------------------------------------------------+
| RD (8 octets) | | RD (8 octets) |
+--------------------------------------------------+ +--------------------------------------------------+
| Ethernet Segment Identifier (10 octets) | | Ethernet Segment Identifier (10 octets) |
skipping to change at page 21, line 13 skipping to change at page 21, line 13
domain. The include/exclude bit helps in creating filters for a domain. The include/exclude bit helps in creating filters for a
given multicast route. given multicast route.
If route is being prepared for IPv6 (MLD) then bit 7 indicates If route is being prepared for IPv6 (MLD) then bit 7 indicates
support for MLD version 1. The second least significant bit, bit 6 support for MLD version 1. The second least significant bit, bit 6
indicates support for MLD version 2. Since there is no MLD version 3, indicates support for MLD version 2. Since there is no MLD version 3,
in case of IPv6 route third least significant bit MUST be 0. In case in case of IPv6 route third least significant bit MUST be 0. In case
of IPv6 route, the fourth least significant bit MUST be ignored if of IPv6 route, the fourth least significant bit MUST be ignored if
bit 6 is not set. bit 6 is not set.
7.2.1 Constructing the Multicast Join Synch Route 9.2.1 Constructing the Multicast Join Synch Route
This section describes the procedures used to construct the IGMP Join This section describes the procedures used to construct the IGMP Join
Synch route. Support for this route type is optional. If a PE does Synch route. Support for this route type is optional. If a PE does
not support this route, then it MUST not indicate that it supports not support this route, then it MUST NOT indicate that it supports
'IGMP proxy' in Multicast Flag extended community for the EVIs 'IGMP proxy' in the Multicast Flag extended community for the EVIs
corresponding to its multi-homed Ethernet Segments. corresponding to its multi-homed Ethernet Segments (ESs).
An IGMP Join Synch route MUST carry exactly one ES-Import Route An IGMP Join Synch route MUST carry exactly one ES-Import Route
Target extended community, the one that corresponds to the ES on Target extended community, the one that corresponds to the ES on
which the IGMP Join was received. It MUST also carry exactly one which the IGMP Join was received. It MUST also carry exactly one
EVI-RT EC, the one that corresponds to the EVI on which the IGMP Join EVI-RT EC, the one that corresponds to the EVI on which the IGMP Join
was received. See Section 7.5 for details on how to form the EVI-RT was received. See Section 9.5 for details on how to encode and
EC. construct the EVI-RT EC.
The Route Distinguisher (RD) SHOULD be a Type 1 RD [RFC4364]. The The Route Distinguisher (RD) SHOULD be a Type 1 RD [RFC4364]. The
value field comprises an IP address of the PE (typically, the value field comprises an IP address of the PE (typically, the
loopback address) followed by a number unique to the PE. loopback address) followed by a number unique to the PE.
The Ethernet Segment Identifier (ESI) MUST be set to the 10-octet The Ethernet Segment Identifier (ESI) MUST be set to the 10-octet
value defined for the ES. value defined for the ES.
The Ethernet Tag ID MUST be set as follows: The Ethernet Tag ID MUST be set as follows:
skipping to change at page 22, line 25 skipping to change at page 22, line 24
The Originator Router Length is the length of the Originator Router The Originator Router Length is the length of the Originator Router
address in bits. address in bits.
The Originator Router Address is the IP address of Router Originating The Originator Router Address is the IP address of Router Originating
the prefix. the prefix.
The Flags field indicates the version of IGMP protocol from which the The Flags field indicates the version of IGMP protocol from which the
membership report was received. It also indicates whether the membership report was received. It also indicates whether the
multicast group had INCLUDE or EXCLUDE bit set. multicast group had INCLUDE or EXCLUDE bit set.
7.3 Multicast Leave Synch Route 9.3 Multicast Leave Synch Route
This EVPN route type is used to coordinate IGMP Leave Group (x,G) This EVPN route type is used to coordinate IGMP Leave Group (x,G)
state for a given BD between the PEs attached to a given ES operating state for a given BD between the PEs attached to a given ES operating
in All-Active (or Single-Active) redundancy mode and it consists of in All-Active (or Single-Active) redundancy mode and it consists of
following: following:
+--------------------------------------------------+ +--------------------------------------------------+
| RD (8 octets) | | RD (8 octets) |
+--------------------------------------------------+ +--------------------------------------------------+
| Ethernet Segment Identifier (10 octets) | | Ethernet Segment Identifier (10 octets) |
skipping to change at page 24, line 18 skipping to change at page 24, line 18
domain. The include/exclude bit helps in creating filters for a domain. The include/exclude bit helps in creating filters for a
given multicast route. given multicast route.
If route is being prepared for IPv6 (MLD) then bit 7 indicates If route is being prepared for IPv6 (MLD) then bit 7 indicates
support for MLD version 1. The second least significant bit, bit 6 support for MLD version 1. The second least significant bit, bit 6
indicates support for MLD version 2. Since there is no MLD version 3, indicates support for MLD version 2. Since there is no MLD version 3,
in case of IPv6 route third least significant bit MUST be 0. In case in case of IPv6 route third least significant bit MUST be 0. In case
of IPv6 route, the fourth least significant bit MUST be ignored if of IPv6 route, the fourth least significant bit MUST be ignored if
bit 6 is not set. bit 6 is not set.
7.3.1 Constructing the Multicas Leave Synch Route 9.3.1 Constructing the Multicast Leave Synch Route
This section describes the procedures used to construct the IGMP This section describes the procedures used to construct the IGMP
Leave Synch route. Support for this route type is optional. If a PE Leave Synch route. Support for this route type is optional. If a PE
does not support this route, then it MUST not indicate that it does not support this route, then it MUST not indicate that it
supports 'IGMP proxy' in Multicast Flag extended community for the supports 'IGMP proxy' in Multicast Flag extended community for the
EVIs corresponding to its multi-homed Ethernet Segments. EVIs corresponding to its multi-homed Ethernet Segments.
An IGMP Leave Synch route MUST carry exactly one ES-Import Route An IGMP Leave Synch route MUST carry exactly one ES-Import Route
Target extended community, the one that corresponds to the ES on Target extended community, the one that corresponds to the ES on
which the IGMP Leave was received. It MUST also carry exactly one which the IGMP Leave was received. It MUST also carry exactly one
EVI-RT EC, the one that corresponds to the EVI on which the IGMP EVI-RT EC, the one that corresponds to the EVI on which the IGMP
Leave was received. See Section 7.5 for details on how to form the Leave was received. See Section 9.5 for details on how to form the
EVI-RT EC. EVI-RT EC.
The Route Distinguisher (RD) SHOULD be a Type 1 RD [RFC4364]. The The Route Distinguisher (RD) SHOULD be a Type 1 RD [RFC4364]. The
value field comprises an IP address of the PE (typically, the value field comprises an IP address of the PE (typically, the
loopback address) followed by a number unique to the PE. loopback address) followed by a number unique to the PE.
The Ethernet Segment Identifier (ESI) MUST be set to the 10-octet The Ethernet Segment Identifier (ESI) MUST be set to the 10-octet
value defined for the ES. value defined for the ES.
The Ethernet Tag ID MUST be set as follows: The Ethernet Tag ID MUST be set as follows:
skipping to change at page 25, line 31 skipping to change at page 25, line 31
The Originator Router Length is the length of the Originator Router The Originator Router Length is the length of the Originator Router
address in bits. address in bits.
The Originator Router Address is the IP address of Router Originating The Originator Router Address is the IP address of Router Originating
the prefix. the prefix.
The Flags field indicates the version of IGMP protocol from which the The Flags field indicates the version of IGMP protocol from which the
membership report was received. It also indicates whether the membership report was received. It also indicates whether the
multicast group had INCLUDE or EXCLUDE bit set. multicast group had INCLUDE or EXCLUDE bit set.
7.4 Multicast Flags Extended Community 9.4 Multicast Flags Extended Community
The 'Multicast Flags' extended community is a new EVPN extended The 'Multicast Flags' extended community is a new EVPN extended
community. EVPN extended communities are transitive extended community. EVPN extended communities are transitive extended
communities with a Type field value of 6. IANA will assign a Sub- communities with a Type field value of 6. IANA will assign a Sub-
Type from the 'EVPN Extended Community Sub-Types' registry. Type from the 'EVPN Extended Community Sub-Types' registry.
A PE that supports IGMP proxy on a given BD MUST attach this extended A PE that supports IGMP proxy on a given BD MUST attach this extended
community to the Inclusive Multicast Ethernet Tag (IMET) route it community to the Inclusive Multicast Ethernet Tag (IMET) route it
advertises for that BD and it Must set the IGMP Proxy Support flag to advertises for that BD and it MUST set the IGMP Proxy Support flag to
1. Note that an [RFC7432] compliant PE will not advertise this 1. Note that an [RFC7432] compliant PE will not advertise this
extended community so its absence indicates that the advertising PE extended community so its absence indicates that the advertising PE
does not support IGMP Proxy. does not support IGMP Proxy.
The advertisement of this extended community enables more efficient The advertisement of this extended community enables more efficient
multicast tunnel setup from the source PE specially for ingress multicast tunnel setup from the source PE specially for ingress
replication - i.e., if an egress PE supports IGMP proxy but doesn't replication - i.e., if an egress PE supports IGMP proxy but doesn't
have any interest in a given (x, G), it advertises its IGMP proxy have any interest in a given (x,G), it advertises its IGMP proxy
capability using this extended community but it does not advertise capability using this extended community but it does not advertise
any SMET route for that (x, G). When the source PE (ingress PE) any SMET route for that (x,G). When the source PE (ingress PE)
receives such advertisements from the egress PE, it does not receives such advertisements from the egress PE, it does not
replicate the multicast traffic to that egress PE; however, it does replicate the multicast traffic to that egress PE; however, it does
replicate the multicast traffic to the egress PEs that don't replicate the multicast traffic to the egress PEs that don't
advertise such capability even if they don't have any interests in advertise such capability even if they don't have any interests in
that (x, G). that (x,G).
A Multicast Flags extended community is encoded as an 8-octet value, A Multicast Flags extended community is encoded as an 8-octet value,
as follows: as follows:
1 2 3 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=0x06 | Sub-Type=TBD | Flags (2 Octets) | | Type=0x06 | Sub-Type=TBD | Flags (2 Octets) |M|I|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved=0 | | Reserved=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The low-order bit of the Flags is defined as the "IGMP Proxy Support" The low-order (lease significant) two bits are defined as the "IGMP
bit. A value of 1 means that the PE supports IGMP Proxy as defined Proxy Support and MLD Proxy Support" bit. The absence of this
in this document, and a value of 0 means that the PE does not support extended community also means that the PE does not support IGMP
IGMP proxy. The absence of this extended community also means that proxy.
the PE does not support IGMP proxy. where:
7.5 EVI-RT Extended Community o Type is 0x06 as registered with IANA for EVPN Extended Communities.
In EVPN, every EVI is associated with one or more Route Targets o Sub-Type : TBD
(RTs). These Route Targets serve two functions:
- Distribution control: RTs control the distribution of the routes. o Flags are two Octets value.
If a route carries the RT associated with a particular EVI, it will
be distributed to all the PEs on which that EVI exists.
- EVI Identification: Once a route has been received by a particular - Bit 15 (shown as I) defines IGMP Proxy Support. Value of 1 for
PE, the RT is used to identify the EVI to which it applies. bit 15 means that PE supports IGMP Proxy. Value of 0 for bit 15
means that PE does not supports IGMP Proxy.
An IGMP Join Synch or IGMP Leave Synch route is associated with a - Bit 14 (shown as M) defines MLD Proxy Support. Value of 1 for
particular combination of ES and EVI. These routes need to be bit 14 means that PE supports MLD Proxy. Value of 0 for bit 14
distributed only to PEs that are attached to the associated ES. means that PE does not support MLD proxy.
Therefore these routes carry the ES-Import RT for that ES.
Since an IGMP Join Synch or IGMP Leave Synch route does not need to - Bit 0 to 13 are reserved for future.
be distributed to all the PEs on which the associated EVI exists,
these routes cannot carry the RT associated with that EVI. Therefore,
when such a route arrives at a particular PE, the route's RTs cannot
be used to identify the EVI to which the route applies. Some other
means of associating the route with an EVI must be used.
This document specifies four new Extended Communities (EC) that can o Reserved bits are set to 0. They could be defined in future.
be used to identify the EVI with which a route is associated, but
which do not have any effect on the distribution of the route. These
new ECs are are known as the "Type 0 EVI-RT EC", the "Type 1 EVI-RT
EC", the "Type 2 EVI-RT EC", and the "Type 3 EVI-RT EC".
A Type 0 EVI-RT EC is an EVPN EC (type 6) of sub-type 0xA. 9.5 EVI-RT Extended Community
In EVPN, every EVI is associated with one or more Route Targets
(RTs). These Route Targets serve two functions:
A Type 1 EVI-RT EC is an EVPN EC (type 6) of sub-type 0xB. - Distribution control: RTs control the distribution of the
routes. If a route carries the RT associated with a particular
EVI, it will be distributed to all the PEs on which that EVI
exists.
A Type 2 EVI-RT EC is an EVPN EC (type 6) of sub-type 0xC. - EVI identification: Once a route has been received by a
particular PE, the RT is used to identify the EVI to which it
applies.
A Type 3 EVI-RT EC is an EVPN EC (type 6) of sub-type TBD. An IGMP Join Synch or IGMP Leave Synch route is associated with a
particular combination of ES and EVI. These routes need to be
distributed only to PEs that are attached to the associated ES.
Therefore these routes carry the ES-Import RT for that ES.
Each IGMP Join Synch or IGMP Leave Synch route MUST carry exactly one Since an IGMP Join Synch or IGMP Leave Synch route does not need
EVI-RT EC. The EVI-RT EC carried by a particular route is to be distributed to all the PEs on which the associated EVI
constructed as follows. Each such route is the result of having exists, these routes cannot carry the RT associated with that
received an IGMP Join or an IGMP Leave message from a particular BD. EVI. Therefore, when such a route arrives at a particular PE, the
We will say that the route is associated with that BD. For each BD, route's RTs cannot be used to identify the EVI to which the route
there is a corresponding RT that is used to ensure that routes applies. Some other means of associating the route with an EVI
"about" that BD are distributed to all PEs attached to that BD. So must be used.
suppose a given IGMP Join Synch or Leave Synch route is associated
with a given BD, say BD1, and suppose that the corresponding RT for
BD1 is RT1. Then:
0. If RT1 is a Transitive Two-Octet AS-specific EC, then the EVI-RT This document specifies four new Extended Communities (EC) that
EC carried by the route is a Type 0 EVI-RT EC. The value field of can be used to identify the EVI with which a route is associated,
the Type 0 EVI-RT EC is identical to the value field of RT1. but which do not have any effect on the distribution of the
route. These new ECs are known as the "Type 0 EVI-RT EC", the
"Type 1 EVI-RT EC", the "Type 2 EVI-RT EC", and the "Type 3 EVI-
RT EC".
1. If RT1 is a Transitive IPv4-Address-specific EC, then the EVI-RT A Type 0 EVI-RT EC is an EVPN EC (type 6) of sub-type
EC carried by the route is a Type 1 EVI-RT EC. The value field of 0xA.
the Type 1 EVI-RT EC is identical to the value field of RT1.
2. If RT1 is a Transitive Four-Octet-specific EC, then the EVI-RT EC A Type 1 EVI-RT EC is an EVPN EC (type 6) of sub-type
carried by the route is a Type 2 EVI-RT EC. The value field of the 0xB.
Type 2 EVI-RT EC is identical to the value field of RT1.
3. If RT1 is a Transitive IPv6-Address-specific EC, then the EVI-RT A Type 2 EVI-RT EC is an EVPN EC (type 6) of sub-type
EC carried by the route is a Type 3 EVI-RT EC. The value field of 0xC.
the Type 3 EVI-RT EC is identical to the value field of RT1.
An IGMP Join Synch or Leave Synch route MUST carry exactly one EVI- A Type 3 EVI-RT EC is an EVPN EC (type 6) of sub-type
RT EC. TBD.
Suppose a PE receives a particular IGMP Join Synch or IGMP Leave Each IGMP Join Synch or IGMP Leave Synch route MUST carry exactly
Synch route, say R1, and suppose that R1 carries an ES-Import RT that one EVI-RT EC. The EVI-RT EC carried by a particular route is
is one of the PE's Import RTs. If R1 has no EVI-RT EC, or has more constructed as follows. Each such route is the result of having
than one EVI-RT EC, the PE MUST apply the "treat-as-withdraw" received an IGMP Join or an IGMP Leave message from a particular
procedure of [RFC7606]. BD. The route is said to be associated associated with that BD.
For each BD, there is a corresponding RT that is used to ensure
that routes "about" that BD are distributed to all PEs attached
to that BD. So suppose a given IGMP Join Synch or Leave Synch
route is associated with a given BD, say BD1, and suppose that
the corresponding RT for BD1 is RT1. Then:
Note that an EVI-RT EC is not a Route Target Extended Community, is 0. If RT1 is a Transitive Two-Octet AS-specific EC, then the EVI-
not visible to the RT Constrain mechanism [RFC4684], and is not RT EC carried by the route is a Type 0 EVI-RT EC. The value
intended to influence the propagation of routes by BGP. field of the Type 0 EVI-RT EC is identical to the value field of
RT1.
1 2 3 1. If RT1 is a Transitive IPv4-Address-specific EC, then the EVI-
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 RT EC carried by the route is a Type 1 EVI-RT EC. The value
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ field of the Type 1 EVI-RT EC is identical to the value field of
| Type=0x06 | Sub-Type=n | RT associated with EVI | RT1.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RT associated with the EVI (cont.) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where the value of 'n' is 0x0A, 0x0B, 0x0C, or 0x0D corresponding to 2. If RT1 is a Transitive Four-Octet-specific EC, then the EVI-RT
EVI-RT type 0, 1, 2, or 3 respectively. EC carried by the route is a Type 2 EVI-RT EC. The value field
of the Type 2 EVI-RT EC is identical to the value field of RT1.
7.6 Rewriting of RT ECs and EVI-RT ECs by ASBRs 3. If RT1 is a Transitive IPv6-Address-specific EC, then the EVI-
RT EC carried by the route is a Type 3 EVI-RT EC. The value
field of the Type 3 EVI-RT EC is identical to the value field of
RT1.
There are certain situations in which an ES is attached to a set of An IGMP Join Synch or Leave Synch route MUST carry exactly one
PEs that are not all in the same AS, or not all operated by the same EVI-RT EC.
provider. In some such situations, the RT that corresponds to a
particular EVI may be different in each AS. If a route is propagated
from AS1 to AS2, an ASBR at the AS1/AS2 border may be provisioned
with a policy that removes the RTs that are meaningful in AS1 and
replaces them with the corresponding (i.e., RTs corresponding to the
same EVIs) RTs that are meaningful in AS2. This is known as RT-
rewriting.
Note that if a given route's RTs are rewritten, and the route carries Suppose a PE receives a particular IGMP Join Synch or IGMP Leave
an EVI-RT EC, the EVI-RT EC needs to be rewritten as well. Synch route, say R1, and suppose that R1 carries an ES-Import RT
that is one of the PE's Import RTs. If R1 has no EVI-RT EC, or
has more than one EVI-RT EC, the PE MUST apply the "treat-as-
withdraw" procedure of [RFC7606].
8 IGMP/MLD Immediate leave Note that an EVI-RT EC is not a Route Target Extended Community,
is not visible to the RT Constrain mechanism [RFC4684], and is
not intended to influence the propagation of routes by BGP.
IGMP MAY be configured with immediate leave option. This allows the 1 2 3
device to remove the group entry from the multicast routing table 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
immediately upon receiving a IGMP leave message for (x,G). In case of +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
all active multi-homing while synchronizing IGMP leave state to | Type=0x06 | Sub-Type=n | RT associated with EVI |
redundancy peers, Maximum Response Time MAY be filled as Zero. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Implementation SHOULD make sure to have identical configuration | RT associated with the EVI (cont.) |
across multi home peer. In case IGMP leave Synch route is received +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
with Maximum Response Time Zero, irrespective of local IGMP
configuration it MAY be processed as immediate leave.
9 IGMP Version 1 membership request Where the value of 'n' is 0x0A, 0x0B, 0x0C, or 0x0D corresponding
to EVI-RT type 0, 1, 2, or 3 respectively.
This document does not provide any detail about IGMPv1 processing. 9.6 Rewriting of RT ECs and EVI-RT ECs by ASBRs
Multicast working group are in process of absoluting uses of IGMPv1
so implementation are RECOMENDED to use IGMPv2 / MLDv1 and above
only.
10 Security Considerations There are certain situations in which an ES is attached to a set
of PEs that are not all in the same AS, or not all operated by
the same provider. In some such situations, the RT that
corresponds to a particular EVI may be different in each AS. If
a route is propagated from AS1 to AS2, an ASBR at the AS1/AS2
border may be provisioned with a policy that removes the RTs that
are meaningful in AS1 and replaces them with the corresponding
(i.e., RTs corresponding to the same EVIs) RTs that are
meaningful in AS2. This is known as RT-rewriting.
Same security considerations as [RFC7432]. Note that if a given route's RTs are rewritten, and the route
carries an EVI-RT EC, the EVI-RT EC needs to be rewritten as
well.
11 IANA Considerations 10 IGMP/MLD Immediate Leave
IANA has allocated the following codepoints from the EVPN Extended IGMP MAY be configured with immediate leave option. This allows
Community sub-types registry. the device to remove the group entry from the multicast routing
table immediately upon receiving a IGMP leave message for (x,G).
In case of all active multi-homing while synchronizing the IGMP
Leave state to redundancy peers, Maximum Response Time MAY be
filled in as Zero. Implementations SHOULD have identical
configuration across multi-homed peers. In case IGMP Leave Synch
route is received with Maximum Response Time Zero, irrespective
of local IGMP configuration it MAY be processed as an immediate
leave.
0x09 Multicast Flags Extended Community [this document] 11 IGMP Version 1 Membership Request
0x0A EVI-RT Type 0 [this document]
0x0B EVI-RT Type 1 [this document]
0x0C EVI-RT Type 2 [this document]
IANA is requested to allocate a new codepoint from the EVPN Extended This document does not provide any detail about IGMPv1
Community sub-types registry for the following. processing. Multicast working group are in process of deprecating
uses of IGMPv1 so it is RECOMMENDED that implementations only use
IGMPv2 and above for IPv4 and MLDv1 and above for IPv6.
0x0D EVI-RT Type 3 [this document] 12 Security Considerations
IANA has allocated the following EVPN route types from the EVPN Route Same security considerations as [RFC7432], [RFC2236], [RFC3376],
Type registry. [RFC2710], [RFC3810].
6 - Selective Multicast Ethernet Tag Route 13 IANA Considerations
7 - IGMP Join Synch Route
8 - IGMP Leave Synch Route
IANA is requested to create a registry, "Multicast Flags Extended IANA has allocated the following codepoints from the EVPN
Community Flags", in the BGP registry. Extended Community sub-types registry.
The Multicast Flags Extended Community contains a 16-bit Flags field. 0x09 Multicast Flags Extended Community [this document]
The bits are numbered 0-15, from low-order to high-order. 0x0A EVI-RT Type 0 [this document]
0x0B EVI-RT Type 1 [this document]
0x0C EVI-RT Type 2 [this document]
The registry should be initialized as follows: IANA is requested to allocate a new codepoint from the EVPN
Extended Community sub-types registry for the following.
0 : IGMP Proxy Support [this document] 0x0D EVI-RT Type 3 [this document]
1-15 : unassigned
The registration policy should be "Standards Action". IANA has allocated the following EVPN route types from the EVPN
Route Type registry.
12 References 6 - Selective Multicast Ethernet Tag Route
7 - Multicast Join Synch Route
8 - Multicast Leave Synch Route
12.1 Normative References IANA is requested to create a registry, "Multicast Flags Extended
Community Flags", in the BGP registry.
The Multicast Flags Extended Community contains a 16-bit Flags
field. The bits are numbered 0-15, from high-order to low-order.
The registry should be initialized as follows:
Bit Name Reference
---- -------------- -------------
0 - 13 Unassigned
14 MLD Proxy Support This document
15 IGMP Proxy Support This document
The registration policy should be "First Come First Served".
14 References
14.1 Normative References
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI Requirement Levels", BCP 14, RFC 2119, DOI
10.17487/RFC2119, March 1997, <http://www.rfc- 10.17487/RFC2119, March 1997, <http://www.rfc-
editor.org/info/rfc2119>. editor.org/info/rfc2119>.
[RFC4360] S. Sangli et al, ""BGP Extended Communities Attribute", [RFC4360] S. Sangli et al, ""BGP Extended Communities Attribute",
February, 2006. February, 2006.
[RFC7432] Sajassi et al., "BGP MPLS Based Ethernet VPN", February, [RFC7432] Sajassi et al., "BGP MPLS Based Ethernet VPN", February,
2015. 2015.
12.2 Informative References [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
Thyagarajan, "Internet Group Management Protocol, Version
3", RFC 3376, October 2002.
[RFC7387] Key, et al., ""A Framework for Ethernet Tree (E-Tree) [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
Service over a Multiprotocol Label Switching (MPLS) Network", October Listener Discovery (MLD) for IPv6", RFC 2710, October
2014. 1999.
[RFC7623] Sajassi, et al., ""Provider Backbone Bridging Combined with [RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
Ethernet VPN (PBB-EVPN)", September 2015. Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
[FC4541] Christensen, M., Kimball, K., and F. Solensky, [RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
"Considerations for IGMP and MLD snooping PEs", 2006. Patel, "Revised Error Handling for BGP UPDATE Messages",
RFC 7606, DOI 10.17487/RFC7606, August 2015.
[RFC3376] Cain, et. al., "Internet Group Management Protocol, Version [RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
3", October 2002. R., Patel, K., and J. Guichard, "Constrained Route
Distribution for Border Gateway Protocol/MultiProtocol
Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
Private Networks (VPNs)"
[RFC3810] Vida & Costa , "Multicast Listener Discovery Version 2 14.2 Informative References
(MLDv2) for IPv6", June 2004
13 Acknowledgement [RFC4541] Christensen, M., Kimball, K., and F. Solensky,
"Considerations for IGMP and MLD snooping PEs", 2006.
14 Contributors 15 Acknowledgement
The authors would like to thank Stephane Litkowski, Jorge Rabadan,
Anoop Ghanwani, Jeffrey Haas for reviewing and providing valuable
comment.
16 Contributors
Mankamana Mishra Mankamana Mishra
Cisco systems Cisco systems
Email: mankamis@cisco.com Email: mankamis@cisco.com
Derek Yeung
Arrcus
Email: derek@arrcus.com
Authors' Addresses Authors' Addresses
Ali Sajassi Ali Sajassi
Cisco Cisco
Email: sajassi@cisco.com Email: sajassi@cisco.com
Samir Thoria Samir Thoria
Cisco Cisco
Email: sthoria@cisco.com Email: sthoria@cisco.com
Keyur Patel Keyur Patel
Arrcus Arrcus
Email: keyur@arrcus.com Email: keyur@arrcus.com
Derek Yeung
Arrcus
Email: derek@arrcus.com
John Drake John Drake
Juniper Juniper
Email: jdrake@juniper.net Email: jdrake@juniper.net
Wen Lin Wen Lin
Juniper Juniper
Email: wlin@juniper.net Email: wlin@juniper.net
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