V-255976

Discussion

IGMP and MLD snooping provides a way to constrain multicast traffic at Layer 2. By monitoring the IGMP or MLD membership reports sent by hosts within a VLAN, the snooping application can set up Layer 2 multicast forwarding tables to deliver specific multicast traffic only to interfaces connected to hosts interested in receiving the traffic, thereby significantly reducing the volume of multicast traffic that would otherwise flood the VLAN.

Check Content

Review the Arista MLS switch configuration to verify that IGMP or MLD snooping has been configured.

Determine which snooping feature is used.

For IGMP:
Verify the PIM that also enables IGMP on an Arista MLS switch VLAN interface by using the "sh run interface vlan8" command:

switch(config)#sh run int vlan8
interface VLAN8
   ip igmp
   pim ipv4 sparse-mode
switch(config)#exit

For MLD:
Verify the Arista MLS switch is configured for MLD snooping on an interface for version 1 and 2. Version 2 is the default MLD version.

switch#sh run | section mld
 mld snooping
   vlan 200

If the Arista switch is not configured to implement IGMP or MLD snooping for each VLAN, this is a finding.