3Com Switch 8800 Advanced Software V5 Configuration Guide

560 CHAPTER 41: IGMP SNOOPING CONFIGURATION
[SwitchA-vlan100] port ethernet 1/1/1 to ethernet 1/1/4
[SwitchA-vlan100] quit
# Enable IGMP Snooping in VLAN 100 and configure the version as 2.
[SwitchA] igmp-snooping
[SwitchA-igmp-snooping] quit
[SwitchA] vlan 100
[SwitchA-vlan100] igmp-snooping enable
[SwitchA-vlan100] igmp-snooping version 2
[SwitchA-vlan100] quit
# Configure Ethernet1/1/3 as a static router port.
[SwitchA] interface ethernet 1/1/3
[SwitchA-Ethernet1/1/3] igmp-snooping static-router-port vlan 100
[SwitchA-Ethernet1/1/3] quit
Troubleshooting IGMP
Snooping
Configuration
Switch Fails in Layer 2
Multicast Forwarding
Symptom
A switch fails to implement Layer 2 multicast forwarding.
Analysis
IGMP Snooping is not enabled.
Solution
1 Enter the display current-configuration command to view the running status of
IGMP Snooping.
2 If IGMP Snooping is not enabled, use the igmp-snooping command to enable
IGMP Snooping globally and then use igmp-snooping enable command to
enable IGMP Snooping in VLAN view.
3 If IGMP Snooping is disabled only for the corresponding VLAN, just use the
igmp-snooping enable command in VLAN view to enable IGMP Snooping in the
corresponding VLAN.
Configured Multicast
Group Policy Fails to
Take Effect
Symptom
Although a multicast group policy has been configured to allow hosts to join
specific multicast groups, the hosts can still receive multicast data addressed to
other multicast groups.
Analysis
■ The ACL rule is incorrectly configured.
■ The multicast group policy is not applied.
■ The function of dropping unknown multicast data is not enabled, so unknown
multicast data is broadcast.
■ Certain ports have been configured as static member ports of multicasts
groups, and this configuration conflicts with the configured multicast group
policy.