Inter-Area LSP Fails to Be Established

Procedure

1. Check whether LDP extension for inter-area LSP is configured.

   Run the display mpls ldp command to check the displayed Longest-match field. If the field is displayed as On, LDP extension for inter-area LSP is enabled. If the field is displayed as Off, LDP extension for inter-area LSP is disabled.

   • If LDP extension for inter-area LSP is disabled, run the longest-match command to enable this function.

2. Check whether the LDP session is correctly established.

   Run the display mpls ldp session command to check the displayed Status field. If LDP session status is Operational, the LDP session is established and in Up state. If LDP session status is not Operational or no LDP session information is displayed, the LDP session is not established.

   • If the LDP session is not established, locate the fault by referring to LDP Session Is Down.

3. Check whether the LDP session matches the route.

   Run the display ip routing-table command to check the fields NextHop and Interface.

   Run the display mpls ldp session verbose command to check the Addresses received from peer field.

   Run the display mpls ldp peer command to check the DiscoverySource field.

   If the field NextHop is contained in the field Addresses received from peer and the values of fields Interface and DiscoverySource are the same, the LDP session matches the route.

   • If the LDP session does not match the route, locate the fault by referring to LDP LSP Is Down.