Basic Concepts In Igmp Snooping - 3Com 5500-EI PWR Install Manual

Figure 6-1 Before and after IGMP Snooping is enabled on Layer 2 device
Multicast packet transmission
without IGMP Snooping
Source
Host A
Receiver
Multicast packets

Basic Concepts in IGMP Snooping

IGMP Snooping related ports
As shown in Figure
and Switch B, Host A and Host C are receiver hosts (namely, multicast group members).
Figure 6-2 IGMP Snooping related ports
Router A
Source
Router port
Member port
Multicast packets
Ports involved in IGMP Snooping, as shown in
Router port: A router port is a port on the Layer 3 multicast device (DR or IGMP querier) side of the
Ethernet switch. In the figure, Ethernet 1/0/1 of Switch A and Ethernet 1/0/1 of Switch B are router
ports. A switch registers all its local router ports in its router port list.
Member port: A member port is a port on the multicast group member side of the Ethernet switch.
In the figure, Ethernet 1/0/2 and Ethernet 1/0/3 of Switch A and Ethernet 1/0/2 of Switch B are
Multicast router
Layer 2 switch
Host C
Receiver
Host B
6-2, Router A connects to the multicast source, IGMP Snooping runs on Switch A
Switch A
Eth1/0/1 Eth1/0/2
Eth1/0/3
Eth1/0/1
Eth1/0/2
Switch B
Multicast packet transmission
when IGMP Snooping runs
Source
Host A
Receiver
Host B
Receiver
Host A
Host B
Receiver
Host C
Host D
Figure 6-2, are described as follows:
2
Multicast router
Layer 2 switch
Host C
Receiver