• All the device ports connected to the source and receivers or routers must be in the same port-
based VLAN.
• The PIM6 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 PIM6 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 MLD snooping and PIM6 SM
traffic snooping, the device initially blocks all PIM6 SM traffic instead of forwarding it. The device
forwards PIM6 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 PIM6 SM traffic
snooping is enabled, the device blocks the PIM6 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, PIM6 SM traffic snooping will not be
supported.
PIM6 SM snooping configuration
Configuring PIM6 SM snooping on a Brocade device consists of the following global and VLAN-specific
tasks.
Perform the following global PIM6 SM snooping task:
• Enabling or disabling PIM6 SM snooping
Perform the following VLAN-specific PIM6 SM snooping tasks:
• Enabling PIM6 SM snooping on a VLAN
• Disabling PIM6 SM snooping on a VLAN

Enabling or disabling PIM6 SM snooping

Use PIM6 SM snooping only in topologies where multiple PIM sparse routers connect through a device.
PIM6 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 PIM6 SM snooping-enabled device displays a warning if it
receives PIM dense join or prune messages.
Perform the following steps to enable PIM6 SM snooping globally.
1. Enable MLD snooping passive globally.
device(config)#ipv6 multicast passive
2. Enable PIM6 SM snooping globally.
device(config)#ipv6 pimsm-snooping
This command enables PIM6 SM traffic snooping. The PIM6 SM traffic snooping feature assumes
that the network has routers that are running PIM6 SM.

PIM6 SM snooping configuration

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