Enabling IGMP Snooping on CoreBuilder 5000 SwitchModules 5-7
Enabling IGMP Snooping on CoreBuilder 5000 SwitchModulesIGMP snooping can be enabled on the foll owing CoreBuilder 5000
SwitchModule s:
■FTE SwitchModule v1.2
■GigaFTE SwitchModules
IGMP snooping on
a CoreBuilder 5000
SwitchModule
When you enable IGMP snooping on either an FTE SwitchModule, v1.2,
or a GigaFTE SwitchModule, the IP multicast bit is enabled in the
module’s Receive Control Register. This causes the module’s receive
state machine to parse all IP packets looking for the IGMP protocol. If
the packet is an IGMP packet, it is directed to the management
processor queue for snooping purposes.
The management processor then learns the multicast address and adds
it to the module’s forwarding tables. When the IP multicast bit in the
module’s Receive Lookup Control Register is enabled, the forwarding
table entries have a 36-bit destination port map. When a packet enters
the module, the processor looks up the address and directs the packet
to the allowed destination port map. Figure 5-4 shows a typica l FTE
DRAM address forwarding entry.
The only difference between the modules w hen IGMP snooping is
enabled is that the IP Multicast Bit is Bit <20> in the FTE, v1.2 module
and Bit<13> in the GigaFTE module.