Igmp Snooping Examples - Planet Networking & Communication WGSW-50040 Configuration Manual

21.3.3 IGMP Snooping Examples

Scenario 1: IGMP Snooping function
Multicast router
Multicast Server 1 Multicast Server 2
Multicast port
IGMP Snooping
Group 1 Group 1 Group 1 Group 2
21-1 Enabling IGMP Snooping function
Figure
Example: As shown in the above figure, a VLAN 100 is configured in the switch and includes ports 1, 2, 6, 10
and 12. Four hosts are connected to port 2, 6, 10, 12 respectively and the multicast router is connected to port
1. As IGMP Snooping is disabled by default either in the switch or in the VLANs, If IGMP Snooping should be
enabled in VLAN 100, the IGMP Snooping should be first enabled for the switch in Global Mode and in VLAN
100 and set port 1 of VLAN 100 to be the mrouter port.
The configuration steps are listed below:
Switch(config)#ip igmp snooping
Switch(config)#ip igmp snooping vlan 100
Switch(config)#ip igmp snooping vlan 100 mrouter interface ethernet 1/1
Multicast Configuration
Suppose two programs are provided in the Multicast Server using multicast address Group1 and Group2,
three of four hosts running multicast applications are connected to port 2, 6, 10 plays program1, while the host
is connected to port 12 plays program 2.
IGMP Snooping listening result:
The multicast table built by IGMP Snooping in VLAN 100 indicates ports 1, 2, 6, 10 in Group1 and ports 1, 12
in Group2.
All the four hosts can receive the program of their choice: ports 2, 6, 10 will not receive the traffic of program 2
and port 12 will not receive the traffic of program 1.
Scenario 2: L2-general-querier
21-21