H3C Technologies H3C S7500E Series Switches - Manual (Page 350)

12-30
Current MLD version is 1
Multicast routing on this interface: enabled
Require-router-alert: disabled
Use the display mld group command to view MLD multicast group information. For example,
# Display the MLD multicast group information on Switch A.
[SwitchA] display mld group
Total 1 MLD Group(s).
Interface group report information
Vlan-interface100(2001::1):
Total 1 MLD Groups reported
Group Address Last Reporter Uptime Expires
ff3e::101 2001::2 00:02:04 00:01:15
As shown above, the MLD reports sent from the hosts are forwarded to Switch A through the proxy
interface, VLAN-interface 100 of Switch B.
Troubleshooting MLD
No Member Information on the Receiver-Side Router
Symptom
When a host sends a message for joining IPv6 multicast group G, there is no member information of
multicast group G on the immediate router.
Analysis
z 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.
z IPv6 multicast routing must be enabled on the router and MLD must be enabled on the interface
connecting to the host.
z 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.
z 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) Check that the networking, interface connections, and IP address configuration are correct.
Check the interface information with the display mld 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 IPv6 address configuration is not correctly done.
2) Check that the IPv6 multicast routing is enabled. Carry out the display current-configuration
command to check whether the multicast ipv6 routing-enable command has been executed. If
not, carry out the multicast ipv6 routing-enable command in system view to enable IPv6
multicast routing. In addition, enable MLD on the corresponding interface.
3) Check the MLD version on the interface. You can use the display mld interface command to
check whether the MLD 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 IPv6 multicast group
G. Carry out the display current-configuration interface command to check whether the mld