NETGEAR GS748T Software Administration Manual page 115

Multicast Forwarding Database Table
The Layer 2 Multicast Forwarding Database (MFDB) is used by the switch to make
forwarding decisions for packets that arrive with a multicast destination MAC address. By
limiting multicasts to only certain ports in the switch, traffic is prevented from going to parts of
the network where that traffic is unnecessary.
When a packet enters the switch, the destination MAC address is combined with the VLAN
ID and a search is performed in the Layer 2 Multicast Forwarding Database. If no match is
found, then the packet is either flooded to all ports in the VLAN or discarded, depending on
the switch configuration. If a match is found, then the packet is forwarded only to the ports
that are members of that multicast group.
Use the MFDB Table page to view the port membership information for all active multicast
address entries. The key for an entry consists of a MAC address. Entries may contain data
for more than one protocol.
To access the MFDB Table page, click Switching
Table.
The following table describes the fields in the MFDB Table.
Field Description
MAC Address The MAC Address to which the multicast MAC address is related.
To search by MAC address, enter the address with the MFDB table entry you want
displayed. Enter six two-digit hexadecimal numbers separated by colons, for
example 00:0f:43:67:89:AB, and then click Go. If the address exists, that entry will
be displayed. An exact match is required.
VLAN ID The VLAN ID to which the multicast MAC address is related.
GS748T Smart Switch
Multicast
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115
IGMP Snooping MFDB
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