MPLS fault: Tracert switches do not display a middle path

If the CE1 tracert CE2, SCUN can show the middle way, on the contrary, if the CE2tracert CE1, the first jump to NE80E, second to CE1, no VPN pathways of the intermediate display.

Fault analysis

Because the user network public network private network is introduced, also can pass directly from the tracert NE40-4 private network, so in the CE1tracert CE2 can show the public network address, this is up to the public.

By default, the VPN message is not enable IP TTL replication function, so thetracert on the CE2 CE1 show only private network path

- end

Processing steps

Perform the following operations on NE80E.

Step 1 executes the command System-View, enter the system view.

Step 2 executes the command MPLS, go to the MPLS view.

Step 3 executes the command TTL propagate public, enabling MPLS public network message IP TTL replication.

Step 4 executes the command TTL propagate VPN, enabling MPLS VPN message IP TTL replication.

Return to step 5 executes the command return to user view, execute the command save, save the configuration changes.

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After completion of the operation, the tracert in the CE2 CE1, can display the middle way. Troubleshooting.

Case summary

Tracert switch MPLS failure does not show the middle path can be solved, to sum up, by default, the VPN message is not enable IP TTL replication, SCUL need toexecute the command TTL propagate VPN to enable this function.