1-35Total 1 IGMP Group reportedGroup Address Last Reporter Uptime Expires224.1.1.1 0.0.0.0 00:00:06 00:02:04When Host A leaves the multicast group, it sends an IGMP leave message to Switch A. Receiving themessage, Switch A removes port GigabitEthernet 2/0/3 from the member port list of the forwarding entryfor the group; however, it does not remove the group or forward the leave message to Router A becauseHost B is still in the group. Use the display igmp-snooping group command to display informationabout IGMP snooping multicast groups. For example:# Display information about IGMP snooping multicast groups on Switch A.[SwitchA] display igmp-snooping groupTotal 1 IP Group(s).Total 1 IP Source(s).Total 1 MAC Group(s).Port flags: D-Dynamic port, S-Static port, C-Copy portSubvlan flags: R-Real VLAN, C-Copy VLANVlan(id):100.Total 1 IP Group(s).Total 1 IP Source(s).Total 1 MAC Group(s).Router port(s):total 1 port.GE2/0/1 (D)IP group(s):the following ip group(s) match to one mac group.IP group address:224.1.1.1(0.0.0.0, 224.1.1.1):Host port(s):total 1 port.GE2/0/4 (D)MAC group(s):MAC group address:0100-5e01-0101Host port(s):total 1 port.GE2/0/4Troubleshooting IGMP Snooping ConfigurationSwitch Fails in Layer 2 Multicast ForwardingSymptomA switch fails to implement Layer 2 multicast forwarding.AnalysisIGMP snooping is not enabled.Solution1) 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 snoopingglobally, 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-snoopingenable command in VLAN view to enable IGMP snooping in the corresponding VLAN.
