Brocade Communications Systems IPMC5000PEF manual PIM SM snooping configuration

PIM SM snooping configuration

NOTE

Use the passive mode of IGMP snooping instead of the active mode. The passive mode assumes that a router is sending group membership queries as well as join and prune messages on behalf of receivers. The active mode configures the device to send group membership queries.

•All the device ports connected to the source and receivers or routers must be in the same port- based VLAN.

•The PIM SM snooping feature assumes that the group source and the device are in different subnets and communicate through a router. The source must be in a different IP subnet than the receivers. A PIM SM router sends PIM join and prune messages on behalf of a multicast group receiver only when the router and the source are in different subnet. When the receiver and source are in the same subnet, they do not need the router in order to find one another. They find one another directly within the subnet.

The device forwards all IP multicast traffic by default. Once you enable IGMP snooping and PIM SM traffic snooping, the device initially blocks all PIM SM traffic instead of forwarding it. The device forwards PIM SM traffic to a receiver only when the device receives a join message from the receiver. Consequently, if the source and the downstream router are in the same subnet, and PIM SM traffic snooping is enabled, the device blocks the PIM SM traffic and never starts forwarding the traffic. This is because the device never receives a join message from the downstream router for the group. The downstream router and group find each other without a join message because they are in the same subnet.

NOTE

If the "route-only" feature is enabled on a Layer 3 Switch, PIM SM traffic snooping will not be supported.

PIM SM snooping configuration

Configuring PIM SM snooping on a Brocade device consists of the following global and VLAN-specific tasks.

Perform the following global PIM SM snooping task:

•Enabling or disabling PIM SM snooping

Perform the following VLAN-specific PIM SM snooping tasks:

•Enabling PIM SM snooping on a VLAN

•Disabling PIM SM snooping on a VLAN

Enabling or disabling PIM SM snooping

Use PIM SM snooping only in topologies where multiple PIM sparse routers connect through a device. PIM SM snooping does not work on a PIM dense mode router which does not send join messages and traffic to PIM dense ports is stopped. A PIM SM snooping-enabled device displays a warning if it receives PIM dense join or prune messages.

To enable PIM sparse snooping globally, enter the ip pimsm-snoopingcommand.

device(config)#ip pimsm-snooping

38	FastIron Ethernet Switch IP Multicast Configuration Guide
	53-1003085-02