V-283882

Discussion

IGMP snooping provides a way to constrain multicast traffic at layer 2. By monitoring the IGMP membership reports sent by hosts within the bridge domain, the snooping application can set up layer 2 multicast forwarding tables to deliver traffic only to ports with at least one interested member within the VPLS bridge, significantly reducing the volume of multicast traffic that would otherwise flood an entire VPLS bridge domain. The IGMP snooping operation applies to both access circuits and pseudowires within a VPLS bridge domain.

Check Content

Review the router configuration to verify IGMP or MLD snooping has been configured for IPv4 and IPv6 multicast traffic, respectively, for each VPLS bridge domain.

Verify igmp-snooping and mld-snooping are enabled using the command below: 

- show service id 10 igmp-snooping all | match "Admin State"

Admin State : Up
IGMP Snooping Admin State : Up

- show service id 10 mld-snooping all | match "Admin State"

Admin State : Up
MLD Snooping Admin State  : Up

If the router is not configured to implement IGMP or MLD snooping for each VPLS bridge domain, this is a finding.