H3C Technologies H3C S10500 Series Switches - Manual (Page 110)

95
Total number of downstreams: 1
1: Vlan-interface200
Protocol: pim-dm, UpTime: 00:04:25, Expires: never
The output shows that Switch A is the RPF neighbor of Switch C and the multicast data from Switch A is
delivered over a GRE tunnel to Switch C.
Troubleshooting multicast routing and forwarding
Multicast static route failure
Symptom
No dynamic routing protocol is enabled on the routers, and the physical status and link layer status of
interfaces are both up, but the multicast static route fails.
Analysis
• If the multicast static route is not configured or updated correctly to match the current network
conditions, the route entry and the configuration information of multicast static route do not exist in
the multicast routing table.
• If a better route is found, the multicast static route might also fail.
Solution
1. Use the display multicast routing-table static command to view the information of multicast static
routes to verify that the multicast static route has been correctly configured and that the route entry
exists in the multicast routing table.
2. Check the type of the next hop interface of the multicast static route. If the interface is not a
point-to-point interface, be sure to specify the next hop address for the outgoing interface when
you configure the multicast static route.
3. Check that the multicast static route matches the specified routing protocol. If a protocol was
specified in multicast static route configuration, enter the display ip routing-table command to
check if an identical route was added by the protocol.
4. Check that the multicast static route matches the specified routing policy. If a routing policy was
specified when the multicast static route was configured, enter the display route-policy command
to check the configured routing policy.
Multicast data fails to reach receivers
Symptom
The multicast data can reach some routers but fails to reach the last-hop router.
Analysis
If a multicast forwarding boundary has been configured through the multicast boundary command, any
multicast packet will be kept from crossing the boundary.
Solution
1. Use the display pim routing-table command to check whether the corresponding (S, G) entries
exist on the router. If so, the router has received the multicast data. Otherwise, the router has not
received the data.