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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
z
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 is
flooded.
Solution
1) Use
the
display acl
command to check the configured ACL rule. Make sure that the ACL rule
conforms 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 check
whether the correct multicast group policy has been applied. If not, use the
group-policy
or
igmp-snooping group-policy
command to apply the correct multicast group policy.
3) Use
the
display current-configuration
command to check whether the function of dropping
unknown multicast data is enabled. If not, use the
igmp-snooping drop-unknown
command to
enable the function of dropping unknown multicast data.