Brocade Multi-Service IronWare Multicast Configuration Guide (Supporting R05.6.00) - Manual (Page 209)

Multi-Service IronWare Multicast Configuration Guide 197
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IPv6 Multicast Listener Discovery snooping
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Configuration requirements
Consider the following configuration requirements:
• IPv6 Multicast Traffic Reduction must be enabled on the device that will be running PIM-SM
snooping. The PIM-SM traffic snooping feature requires IPv6 Multicast Traffic Reduction.
NOTE
Use the passive mode of IPv6 Multicast Traffic Reduction 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 subnets. 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 IPv6 multicast traffic by default. Once you enable IPv6 Multicast Traffic
Reduction 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, PIM-SM traffic snooping is not supported.
Globally enabling IPv6 PIM SM traffic snooping
This feature is similar to PIM-SM traffic snooping but listens only for MLD snooping information, not
PIM-SM information. You must enable both IPv6 Multicast Traffic Reduction and IPv6 PIM-SM
traffic snooping to enable the device to listen for PIM-SM join and prune messages.
To enable IPv6 PIM-SM traffic snooping, enter the following commands at the global CONFIG level
of the CLI.
Brocade(config)# ipv6 multicast active
Brocade(config)# ipv6 multicast pimsm-snooping
Syntax: [no] ipv6 multicast [active | passive]
When you enable IP multicast on device, all ports on the device are configured for IGMP.
If you are using active MLD, all ports can send MLD queries and receive MLD reports. If you are
using passive MLD, all ports can receive MLD queries.
IPv6 Multicast Traffic Reduction cannot be disabled on individual ports of a device. IPv6 Multicast
Traffic Reduction can be disabled globally by entering the no ipv6 multicast command.
Syntax: [no] ipv6 multicast pimsm-snooping