H3C Technologies H3C SecPath F1000-E - Manual (Page 941)

916
Analysis
• The correctness of networking and interface connections and whether the protocol layer of the
interface is up directly affect the generation of IPv6 group member information.
• IPv6 multicast routing must be enabled on the router and MLD must be enabled on the interface
connecting to the host.
• If the MLD version on the router interface is lower than that on the host, the router will not be able
to recognize the MLD report from the host.
• If the mld group-policy command has been configured on an interface, the interface cannot receive
report messages that fail to pass filtering.
Solution
1. Use the display mld interface command to verify that the networking, interface connections, and IP
address configuration are correct. If no information is 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 IPv6 address configuration is not correctly done.
2. Use the display current-configuration command to verify that IPv6 multicast routing is enabled. If
not, use the multicast ipv6 routing-enable command in system view to enable IPv6 multicast routing.
In addition, enable MLD on the corresponding interface.
3. Use the display mld interface command to verify that the MLD version on the interface is lower than
that on the host.
4. Use the display current-configuration interface command to verify that no ACL rule has been
configured to restrict the host from joining IPv6 multicast group G. If an IPv6 ACL is configured to
restrict the host from joining IPv6 multicast group G, the ACL must be modified to allow IPv6
multicast group G to receive report messages.
Inconsistent memberships on routers on the same subnet
Symptom
Different memberships are maintained on different MLD routers on the same subnet.
Analysis
• A router running MLD maintains multiple parameters for each interface, and these parameters
influence one another, forming very complicated relationships. Inconsistent MLD interface
parameter configurations for routers on the same subnet will surely result in inconsistent MLD
memberships.
• Two MLD versions are available. Although routers running different MLD versions are compatible
with hosts, all routers on the same subnet must run the same MLD version. Inconsistent MLD versions
running on routers on the same subnet will also lead to inconsistent MLD memberships.
Solution
1. Use the display current-configuration command to verify the MLD configuration on the interface.
2. Use the display mld interface command on all routers on the same subnet to check the MLD timers
for inconsistent configurations.
3. Use the display mld interface command to check that the routers are running the same MLD
version.