4000 Router Series IP Multicast Configuration Guide

120

Other querier present time for MLD: 255s

Maximum query response time for MLD: 10s

Querier for MLD: FE80::200:5EFF:FE66:5100 (this router)

MLD groups reported in total: 1

Troubleshooting MLD

No member information exists on the receiver-side router

Symptom

When a host sends a message to announce its joining IPv6 multicast group G, no member information

of multicast group G exists on the immediate router.

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. 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 cannot 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 the command does not produce output, the interface is in an

abnormal state. The reason might be that you have configured the shutdown command on the

interface, that the interface is not correctly connected, or that the IPv6 address configuration is not

correctly done.

2. Use the display current-configuration command to verify that the IPv6 multicast routing is enabled.

If it is not enabled, use the ipv6 multicast routing command in system view to enable IPv6 multicast

routing. In addition, verify that MLD is enabled on the associated interfaces.

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 filter out the reports sent by the host to the IPv6 multicast group G.

Inconsistent membership information on the routers on the same

subnet

Symptom

Different memberships are maintained on different MLD routers on the same subnet.