A mixed installation is a switch configuration that contains I/O modules with different table sizes. The actual IP multicast group table capacity for the switch is set to that supported on the I/O module with the smallest tables. To increase the capacity of IP multicast tables, all I/O modules must support the minimum table size you want.
Multicast forwarding entries are programmed in all I/O modules. Only multicast traffic ingressing a given I/O module utilize these forwarding entries. Other egress-only I/O modules only require the multicast group table entry.
If you add a higher-capacity I/O module to a switch that has been running with lower capacity modules, the switch generates a message and adjusts the table capacity on the higher-capacity card to that of the lower-capacity card.
Compared to the L3 hash table that uses an IP address for forwarding, the L2 table uses a MAC address. The L2 table stores unicast and multicast MAC entries, and it supports <DMAC, VLAN> lookup. The entry from this table provides an index to the L2MC table that specifies the egress ports.
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