772 | PIM Sparse-Modew w w . d e l l . c o m | s u p p o r t . d e l l . c o m PIM-SM Snooping ConfigurationYou can enable PIM-SM snooping globally on a switch or on individual VLANs. PIM-SM snooping is notenabled by default and does not require an IP address, PIM-DM, or PIM-SM.PIM-SM snooping and PIM multicast routing are mutually exclusive: PIM-SM snooping cannot beenabled on a switch/router if PIM-SM or PIM-DM is enabled.If enabled at the global level, PIM-SM snooping is automatically enabled on all VLANs on the switchunless the no ip pim snooping command has been entered on a VLAN interface.If enabled at the VLAN level, PIM-SM snooping requires that you also enter the no shutdown command toenable the interface.Enable PIM SnoopingTo enable PIM-SM snooping on all VLAN interfaces on a switch, enter the following command.To enable PIM-SM snooping on a VLAN interface, enter the following commands:Disable PIM Designated-Router FloodingBy default, when you enable PIM-SM snooping, a switch floods all multicast traffic to the PIM designatedrouter (DR), including unnecessary multicast packets. To minimize the traffic sent over the network to thedesignated router, you can disable designated-router flooding.When designated-router flooding is disabled, PIM-SM snooping only forwards multicast traffic, whichbelongs to a multicast group for which the switch receives a join request, on the port connected towards thedesignated router.To disable designated-router flooding for PIM-SM snooping, enter the no ip pim snooping dr-floodcommand:Task Command Command ModeEnable PIM-SM snooping globally on a switch. ip pim snooping enable CONFIGURATIONTask Command Command ModeEnable PIM-SM snooping on a VLAN interface. ip pim snooping VLAN INTERFACEEnable the interface. no shutdown VLAN INTERFACETask Command Command ModeDisable flooding of multicast packets to thedesignated-router.no ip pim snooping dr-flood CONFIGURATION
