IGMP Snooping
IGMP snooping requires the LAN switch to examine, or snoop, some Layer 3 information in the IGMP packets sent between the hosts and the router. When the switch hears the IGMP host report from a host for a particular multicast group, the switch adds the host's port number to the associated multicast table entry. When the switch hears the IGMP leave group message from a host, it removes the host's port from the table entry.
Multicast Forwarding
In multicast routing, the source is sending traffic to an arbitrary group of hosts represented by a multicast group address. The multicast router must determine which direction is upstream (toward the source) and which direction (or directions) is downstream. If there are multiple downstream paths, the router replicates the packet and forwards the traffic down the appropriate downstream paths - which is not necessarily all paths.
The switch can support IP multicast if IGMP protocol is enabled. IGMP snooping function and status is also provided. Each IP multicast address is associated one Vlan ID and its member ports. The information is available from management interfaces.
1.5.3 MAC Address Filtering Function
MAC address filtering allows the switch to drop unwanted traffic. Incoming traffic is filtered based on the destination MAC addresses (DAs). The unwanted destination addresses are called filter MAC addresses.
The switch provides management function that allows LAN administrator to maintain the filter MAC address table.
