H3C Technologies H3C S7500E Series Switches - Manual (Page 137)

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Solution
1) Check that the networking, interface connection, and IP address configuration are correct.
Check the interface information with the display igmp interface command. If there is no
information output, the interface is in an abnormal state. This is usually because you have
configured the shutdown command on the interface, the interface is not properly
connected, or the IP address configuration is not correctly done.
2) Check that multicast routing is enabled. Carry out the display current-configuration
command to check whether the multicast routing-enable command has been executed. If
not, carry out the multicast routing-enable command in system view to enable IP
multicast routing. In addition, check that IGMP is enabled on the corresponding interfaces.
3) Check the IGMP version on the interface. You can use the display igmp interface
command to check whether the IGMP version on the interface is lower than that on the
host.
4) Check that no ACL rule has been configured to restrict the host from joining the multicast
group G. Carry out the display current-configuration interface command to check
whether the igmp group-policy command has been executed. If the host is restricted from
joining the multicast group G, the ACL rule must be modified to allow receiving the reports
for the multicast group G.
Inconsistent Memberships on Routers on the Same Subnet
Symptom
Different memberships are maintained on different IGMP routers on the same subnet.
Analysis
z A router running IGMP maintains multiple parameters for each interface, and these
parameters influence one another, forming very complicated relationships. Inconsistent
IGMP interface parameter configurations for routers on the same subnet will surely result in
inconsistency of memberships.
z In addition, although an IGMP router is compatible with a host that is running a different
IGMP version, all routers on the same subnet must run the same version of IGMP.
Inconsistent IGMP versions running on routers on the same subnet will also lead to
inconsistency of IGMP memberships.
Solution
1) Check the IGMP configuration. Carry out the display current-configuration command to
view the IGMP configuration information on the interfaces.
2) Carry out the display igmp interface command on all routers on the same subnet to check
the IGMP-related timer settings. Make sure that the settings are consistent on all the
routers.
3) Use the display igmp interface command to check whether all the routers on the same
subnet are running the same version of IGMP.