EVPN OISM configuration guidelines

This section shows a configuration example for the network illustrated in Figure 1.

Figure 1. EVPN OISM example

The following CLI excerpt shows the configuration required on PE4 for services 2000 (VPRN), BD-2003 and BD-2004 (ordinary BDs) and BD-2002 (SBD).

vprn 2000 name "tenant-2k" customer 1 create
    route-distinguisher auto-rd
    interface "bd-2003" create
        address 10.41.0.1/24
        vpls "bd-2003"
        exit                  
    exit
    interface "bd-2004" create
        address 10.42.0.1/24
        vpls "bd-2004"
        exit
    exit
    interface "bd-2002" create
        vpls "bd-2002"
            evpn-tunnel supplementary-broadcast-domain  <------
        exit
    exit
    igmp                      <------
        interface "bd-2003"   <------
            no shutdown
        exit
        interface "bd-2004"   <------
            no shutdown
        exit
        no shutdown
    exit
    pim                       <------
        interface "bd-2002"      <------
            multicast-senders always     <------
        exit
        apply-to all             <------
        no shutdown
    exit
    no shutdown
exit

As shown in the previous configuration commands, the VPRN must be configured as follows.

Besides the VPRN, BD-2003, BD-2004 and BD-2002 (SBD) must be configured as follows.

vpls 2003 name "bd-2003" customer 1 create
    allow-ip-int-bind
        forward-ipv4-multicast-to-ip-int    <------
    exit
    bgp
    exit
    bgp-evpn
        evi 2003
        mpls bgp 1
            ingress-replication-bum-label
            auto-bind-tunnel
                resolution any
            exit
            no shutdown
        exit
    exit
    igmp-snooping                            <------
        no shutdown                          <------
    exit
    sap 1/1/1:2003 create
        igmp-snooping
            mrouter-port
        exit                  
        no shutdown
    exit
    no shutdown
exit
vpls 2004 name "bd-2004" customer 1 create
    allow-ip-int-bind
        forward-ipv4-multicast-to-ip-int     <------
    exit
    bgp
    exit
    bgp-evpn
        evi 2004
        mpls bgp 1
            ingress-replication-bum-label
            auto-bind-tunnel
                resolution any
            exit
            no shutdown
        exit
    exit
    igmp-snooping                            <------
        no shutdown                          <------
    exit
    sap 1/1/1:2004 create
        igmp-snooping
            fast-leave
        exit
        no shutdown
    exit
    no shutdown
exit
vpls 2002 name "bd-2002" customer 1 create
    allow-ip-int-bind
        forward-ipv4-multicast-to-ip-int     <------
    exit
    bgp
    exit
    bgp-evpn
        no mac-advertisement
        ip-route-advertisement
        sel-mcast-advertisement              <------
        evi 2002
        mpls bgp 1
            auto-bind-tunnel
                resolution any
            exit
            no shutdown
        exit
    exit
    igmp-snooping                            <------
        no shutdown                          <------
    exit
    no shutdown
exit

As shown in the previous configuration commands, igmp-snooping no shutdown must be configured in ordinary and SBD R-VPLS services so that IGMP messages or SMET routes are processed by the IGMP module. Also, the command forward-ipv4-multicast-to-ip-int allows the system to forward multicast traffic from the R-VPLS to the VPRN interface.

Finally, bgp-evpn>sel-mcast-advertisement must be enabled on the SBD R-VPLS, so that the SBD aggregates the multicast state for all the ordinary BDs and advertises the corresponding SMET routes with the SBD route-target. In OISM mode, the SMET route is only advertised from the SBD R-VPLS and not from the other ordinary BD R-VPLSes.

PE2 and PE3 are configured with the VPRN (2000), ordinary BD (BD-2001) and SBD (BD-2002) as above. In addition, PE2 and PE3 are attached to ES-1 where a receiver is connected. Multicast state synchronization through BGP Multicast Synch routes is automatically enabled in R-VPLS services in OISM mode and no additional configuration is needed:

/* Example of ES-1 configuration and MCS on PE3. Similar configuration is needed in 
PE2.
bgp-evpn
    ethernet-segment "ES-1" virtual create
        esi 01:00:00:00:00:00:01:00:00:00
        service-carving
            mode manual
            manual
                preference non-revertive create
                    value 30
                exit
            exit
        exit
        multi-homing single-active
        lag 1
        dot1q
            q-tag-range 2001
        exit
        no shutdown
    exit

When the previous configuration is executed in the three nodes, the EVPN routes are exchanged. BD2003 in PE4 receives IMET routes from the remote SBD PEs and creates "SBD" destinations to PE2 and PE3. Those SBD destinations are used to forward multicast traffic to PE2 and PE3, following the OISM forwarding procedures described in OISM forwarding plane. The following command shows an example of IMET route (flagged as SBD route working on OISM mode) and SMET route received on PE4 from PE2.

/* IMET route received from PE2 on PE4.
*A:PE-4# show router bgp routes evpn incl-mcast community target:64500:2002 hunt 
<snip>
-------------------------------------------------------------------------------
RIB In Entries
-------------------------------------------------------------------------------
Nexthop        : 192.0.2.2
From           : 192.0.2.2
Res. Nexthop   : 192.168.24.1
Local Pref.    : 100                    Interface Name : int-PE-4-PE-2
<snip>
Community      : target:64500:2002
                 mcast-flags:SBD/NO-MEG/NO-PEG/OISM/NO-MLD-Proxy/NO-IGMP-Proxy <---
                 bgp-tunnel-encap:MPLS
<snip>
EVPN type      : INCL-MCAST             
Tag            : 0                      
Originator IP  : 192.0.2.2                   <------
Route Dist.    : 192.0.2.2:2002
<snip>
-------------------------------------------------------------------------------
PMSI Tunnel Attributes : 
Tunnel-type    : Ingress Replication    
Flags          : Type: RNVE(0) BM: 0 U: 0 Leaf: not required
MPLS Label     : LABEL 524241           
Tunnel-Endpoint: 192.0.2.2
-------------------------------------------------------------------------------
/* SMET route from PE2 received on PE4.
*A:PE-4# show router bgp routes evpn smet community target:64500:2002 hunt       
<snip>
-------------------------------------------------------------------------------
RIB In Entries
-------------------------------------------------------------------------------
Nexthop        : 192.0.2.2
From           : 192.0.2.2
Res. Nexthop   : 192.168.24.1
Local Pref.    : 100                    Interface Name : int-PE-4-PE-2
<snip>
Community      : target:64500:2002 bgp-tunnel-encap:MPLS
<snip>
EVPN type      : SMET                   
Tag            : 0                      
Src IP         : 0.0.0.0                 <------
Grp IP         : 239.0.0.4               <------
Originator IP  : 192.0.2.2               <------
Route Dist.    : 192.0.2.2:2002         
<snip>

When PE4 receives the IMET routes from PE2 and PE3 SBDs, it identifies the routes as SBD routes in OISM mode, and PE4 creates special EVPN destinations on the BD-2003 service that are used to forward the multicast traffic. The SBD destinations are shown as Sup BCast Domain in the show command output.

*A:PE-4# show service id 2003 evpn-mpls 
===============================================================================
BGP EVPN-MPLS Dest
===============================================================================
TEP Address     Egr Label     Num. MACs   Mcast           Last Change
                Transport:Tnl                             Sup BCast Domain <---
-------------------------------------------------------------------------------
192.0.2.2       524241        0           m               11/26/2019 10:38:04
                ldp:65537                                 Yes   <------
192.0.2.3       524253        0           m               11/26/2019 10:38:28
                ldp:65539                                 Yes   <------
-------------------------------------------------------------------------------
Number of entries : 2
-------------------------------------------------------------------------------

Based on the reception of the SMET routes from PE2 and PE3, PE4 adds the SBD EVPN destinations to its MFIB on BD-2003.

*A:PE-4# show service id 2003 igmp-snooping base 
===============================================================================
IGMP Snooping Base info for service 2003
===============================================================================
Admin State : Up
Querier     : 10.41.0.1 on rvpls bd-2003
SBD service : 2002
-------------------------------------------------------------------------------
Port                      Oper MRtr Pim  Send Max   Max  Max   MVR       Num
Id                        Stat Port Port Qrys Grps  Srcs Grp   From-VPLS Grps
                                                         Srcs            
-------------------------------------------------------------------------------
sap:1/1/1:2003            Up   Yes  No   No   None  None None  Local     0
rvpls                     Up   Yes  No   N/A  N/A   N/A  N/A   N/A       N/A
sbd-mpls:192.0.2.2:524241 Up   No   No   N/A  N/A   N/A  N/A   N/A       1 <------
sbd-mpls:192.0.2.3:524253 Up   No   No   N/A  N/A   N/A  N/A   N/A       1 <------
===============================================================================
*A:PE-4# show service id 2003 igmp-snooping statistics 
===============================================================================
IGMP Snooping Statistics for service 2003
===============================================================================
Message Type            Received      Transmitted   Forwarded
-------------------------------------------------------------------------------
<snip>
EVPN SMET Routes        2             0             N/A    <------
-------------------------------------------------------------------------------
*A:PE-4# show service id 2003 mfib                                               
<snip>
-------------------------------------------------------------------------------
*               *                     sap:1/1/1:2003               Local    Fwd
*               239.0.0.4             sap:1/1/1:2003               Local    Fwd
                                      sbd-eMpls:192.0.2.2:524241   Local    Fwd
                                      sbd-eMpls:192.0.2.3:524253   Local    Fwd

PE2 and PE3 also creates regular destinations and SBD destinations based on the reception of IMET routes. As an example, the show service id 2001 evpn-mpls command shows the destinations created by PE3 in the ordinary BD-2001.

*A:PE-3# show service id 2001 evpn-mpls 
===============================================================================
BGP EVPN-MPLS Dest
===============================================================================
TEP Address     Egr Label     Num. MACs   Mcast           Last Change
                Transport:Tnl                             Sup BCast Domain <------
-------------------------------------------------------------------------------
192.0.2.2       524241        0           m               11/26/2019 10:38:28
                ldp:65538                                 Yes              <------
192.0.2.2       524242        0           bum             11/26/2019 10:38:28
                ldp:65538                                 No 
192.0.2.2       524243        1           none            11/26/2019 10:38:28
                ldp:65538                                 No
192.0.2.4       524245        0           m               11/26/2019 10:38:28
                ldp:65537                                 Yes              <------
-------------------------------------------------------------------------------
Number of entries : 4
-------------------------------------------------------------------------------
===============================================================================

In case of an SBD destination and a non-SBD destination to the same PE (PE2), IGMP only uses the non-SBD one in the MFIB. The non-SBD destination always has priority over the SBD destination. This can be seen in the show service id igmp-snooping base command in PE3, where the SBD destination to PE2 is down as long as the non-SBD destination is up.

*A:PE-3# show service id 2001 igmp-snooping base 
===============================================================================
IGMP Snooping Base info for service 2001
===============================================================================
Admin State : Up
Querier     : 10.0.0.3 on rvpls bd-2001
SBD service : 2002
-------------------------------------------------------------------------------
Port                      Oper MRtr Pim  Send Max   Max  Max   MVR       Num
Id                        Stat Port Port Qrys Grps  Srcs Grp   From-VPLS Grps
                                                         Srcs            
-------------------------------------------------------------------------------
sap:lag-1:2001            Down No   No   No   None  None None  Local     1
rvpls                     Up   Yes  No   N/A  N/A   N/A  N/A   N/A       N/A
sbd-mpls:192.0.2.2:524241 Down No   No   N/A  N/A   N/A  N/A   N/A       0 <------
mpls:192.0.2.2:524242     Up   No   No   N/A  N/A   N/A  N/A   N/A       1 <------
sbd-mpls:192.0.2.4:524245 Up   No   No   N/A  N/A   N/A  N/A   N/A       0 
===============================================================================
*A:PE-3# show service id 2001 mfib 
===============================================================================
Multicast FIB, Service 2001
===============================================================================
Source Address  Group Address         Port Id                      Svc Id   Fwd
                                                                            Blk
-------------------------------------------------------------------------------
*               239.0.0.4             sap:lag-1:2001               Local    Fwd
                                      eMpls:192.0.2.2:524242       Local    Fwd <---

Finally, to check the Layer 3 IIF and OIF entries on the VPRN services, enter the show router id pim group detail command. As an example, the command is executed in PE2:

*A:PE-2# show router 2000 pim group detail         
===============================================================================
PIM Source Group ipv4
===============================================================================
Group Address      : 239.0.0.4
Source Address     : *
<snip>
===============================================================================
PIM Source Group ipv4
===============================================================================
Group Address      : 239.0.0.4
Source Address     : 10.41.0.41
<snip>
Up Time            : 0d 00:13:20        Resolved By        : rtable-u 
Up JP State        : Joined             Up JP Expiry       : 0d 00:00:00
Up JP Rpt          : Pruned             Up JP Rpt Override : 0d 00:00:00
 
Rpf Neighbor       : 10.41.0.41
Incoming Intf      : bd-2002
Outgoing Intf List : bd-2001
 
Curr Fwding Rate   : 0.000 kbps         
Forwarded Packets  : 1000               Discarded Packets  : 0
Forwarded Octets   : 84000              RPF Mismatches     : 0
Spt threshold      : 0 kbps             ECMP opt threshold : 7
Admin bandwidth    : 1 kbps             
-------------------------------------------------------------------------------
Groups : 2
===============================================================================