3Com 5000 ATM manual Shows a typical packet path before snooping occurs

Overview 5-3

Figure 5-1 shows a typical packet path before snooping occurs.

Multicast

Router

Host 3

Host 1

Eliminating unwanted IP multicast protocols

	CoreBuilder® 5000 Hub
Host 3 sends a
Multicast Packet

Host 2

Figure 5-1Multicast Packet Path before Snooping

IGMP snooping switch and multicast MAC address filters work together to eliminate unwanted IP multicast routing protocols as follows:

■The IGMP snooping switch filters IP multicast packets based on IGMP/IP and IP multicast packets to only the subset of ports that are in a multicast group.

■The multicast MAC address filters restrict multicast packets to only the subset of ports that request this traffic, thus freeing up bandwidth for useful traffic.