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Troubleshooting Multicast Routing and Forwarding
Multicast Static Route Failure
Symptom
No dynamic routing protocol is enabled on the routers, and the physic status and link layer status of
interfaces are both up, but the multicast static route fails.
Analysis
z
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 routes do not exist in
the multicast routing table.
z
If the optimal route is found, the multicast static route may also fail.
Solution
1) In the configuration, you can use the
display multicast routing-table static config
command to
view the detailed configuration information of multicast static routes to verify that the multicast
static route has been correctly configured and the route entry exists.
2) In the configuration, you can 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 the route entry exists in the multicast routing table.
3) Check the next hop interface type of the multicast static route. If the interface is not a point-to-point
interface, be sure to specify the next hop address to configure the outgoing interface when you
configure the multicast static route.
4) 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.
5) 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.
2) Use
the
display multicast boundary
command to view the multicast boundary information on the
interfaces. Use the
multicast boundary
command to change the multicast forwarding boundary
setting.
