3Com S7906E - Switch, Configuration Manual

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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.