PIM Snooping
Switch restricts multicast packets for each IP multicast group to only those multicast router ports that have downstream receivers joined to that group
- Learn within specific VLAN listening to PIM hello messages, PIM join and prune and Bidrectional PIM designated forwarder election
- Must enable IGMP snooping on switch to use PIM snooping
- IGMP snooping restricts multicast traffic that exits through the LAN port to which hosts are connected
- IGMP snooping does not restrict traffic that exists through the LAN ports to which one or more multicast routers are connected
Disabled by default
- Must use PIM-SM
- Dense mode is seen as unknown traffic and is dropped
- Auto-RP groups (224.0.1.39 and 224.0.1.40) is always flooded
- Can enable and disable on per-VLAN basis
Configuration
- Ip pim snooping – Global or under vlan interface
- Show ip pim snooping
Router(config)# ip pim snooping Router# show ip pim snooping Global runtime mode: Enabled Global admin modeĀ : Enabled Number of user enabled VLANs: 1 User enabled VLANs: 10 Router#