1-27Troubleshooting 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.Configured Multicast Group Policy Fails to Take EffectSymptomAlthough 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.Analysisz The ACL rule is incorrectly configured.z The multicast group policy is not correctly applied.z The function of dropping unknown multicast data is not enabled, so unknown multicast data isflooded.Solution1) Use the display acl command to check the configured ACL rule. Make sure that the ACL ruleconforms to the multicast group policy to be implemented.2) Use the display this command in IGMP Snooping view or in the corresponding port view to checkwhether the correct multicast group policy has been applied. If not, use the group-policy origmp-snooping group-policy command to apply the correct multicast group policy.3) Use the display current-configuration command to check whether the function of droppingunknown multicast data is enabled. If not, use the igmp-snooping drop-unknown command toenable the function of dropping unknown multicast data.
