Whenever igmp-proxy is added or deleted in Ethernet VPN (EVPN), the __ves__ flood goes missing, which causes an impact on the BUM traffic. The same issue is seen in the lab when both ESI/IGMP-proxy are added or deleted, and also for any interface-related configuration changes, irrespective of whether they are EVPN interfaces or others.

Restarting the router provides temporary recovery, but the problem can recur.

This article provides a more permanent solution to this problem.

The following outputs show " _ves_ " group values before and after a configuration change:

labroot@jtac-acx5448-m-r2004# run show evpn flood
Name: L2-MCAST-TBN
CEs: 1
VEs: 1
Flood Routes:
  Prefix    Type          Owner                 NhType          NhIndex
  0x30003/51 FLOOD_GRP_COMP_NH __ves__          comp            600   
  0x30004/51 FLOOD_GRP_COMP_NH __all_ces__      comp            583   
  0x30000/51 FLOOD_GRP_COMP_NH __re_flood__     comp            584   

[edit]
labroot@jtac-acx5448-m-r2004# set routing-instances L2-MCAST-TBN protocols igmp-snooping proxy

[edit]
labroot@jtac-acx5448-m-r2004# commit
commit complete

[edit]
labroot@jtac-acx5448-m-r2004# run show evpn flood                                               
Name: L2-MCAST-TBN
CEs: 1
VEs: 0 <<<<<<< Count is zero and the entry is missing. 
Flood Routes:
  Prefix    Type          Owner                 NhType          NhIndex
  0x30004/51 FLOOD_GRP_COMP_NH __all_ces__      comp            583   
  0x30000/51 FLOOD_GRP_COMP_NH __re_flood__     comp            584   

[edit]
labroot@jtac-acx5448-m-r2004# show | compare rollback 1
[edit routing-instances L2-MCAST-TBN protocols]
-     igmp-snooping {
-         proxy;
-     }

[edit]
labroot@jtac-acx5448-m-r2004# run show evpn flood
Name: L2-MCAST-TBN
CEs: 1
VEs: 0
Flood Routes:
  Prefix    Type          Owner                 NhType          NhIndex
  0x30004/51 FLOOD_GRP_COMP_NH __all_ces__      comp            583   
  0x30000/51 FLOOD_GRP_COMP_NH __re_flood__     comp            584    

The problem occurs because router-id is not being set due to which a Type-3 route with a proper PMSI-Ingress Replicator IP address is not being populated.

To address this issue, configure a router-id on the devices by using the following:

set routing-options router-id a.b.c.d

After a router-id is configured, the EVPN will be UP and stable, with the " _ves_ " flood group intact.