Troubleshooting Multicast Routing And Forwarding; Multicast Static Route Failure - 3Com S7906E Configuration Manual

1: Vlan-interface200
Protocol: igmp, UpTime: 00:04:25, Expires: never
(10.1.1.100, 225.1.1.1)
Protocol: pim-dm, Flag: ACT
UpTime: 00:06:14
Upstream interface: Tunnel0
Upstream neighbor: 50.1.1.1
RPF prime neighbor: 50.1.1.1
Downstream interface(s) information:
Total number of downstreams: 1
1: Vlan-interface200
Protocol: pim-dm, UpTime: 00:04:25, Expires: never
As shown above, 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 physic 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 routes do not exist in
the multicast routing table.
If a better 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.
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