Step 1: Verify the LSP

Purpose

Typically, you use the show mpls lsp extensive command to verify the LSP. However for quick verification of the LSP state, use the show mpls lsp command. If the LSP is down, use the extensive option (show mpls lsp extensive) as a follow-up. If your network has numerous LSPs, you might consider specifying the name of the LSP, using the name option (show mpls lsp name name or show mpls lsp name name extensive).

Action

To determine whether the LSP is up, enter the following command from the ingress router:

user@host> show mpls lsp extensive

Sample Output 1

user@R1> show mpls lsp extensive

Ingress LSP: 1 sessions

10.0.0.6

  From: 10.0.0.1, State: Dn, ActiveRoute: 0, LSPname: R1-to-R6

  ActivePath: (none)

  LoadBalance: Random

  Encoding type: Packet, Switching type: Packet, GPID: IPv4

  Primary                    State: Dn

    Will be enqueued for recomputation in 25 second(s).

   44 Oct 15 16:56:11 CSPF failed: no route toward 10.0.0.6[2685 times]

   43 Oct 14 19:07:09 Clear Call

   42 Oct 14 19:06:56 Deselected as active

   41 Oct 14 19:06:56 10.1.12.1: MPLS label allocation failure

   40 Oct 14 19:06:56 Down

   39 Oct 14 18:43:43 Selected as active path

   38 Oct 14 18:43:43 Record Route:  10.1.13.2 10.1.36.2

   37 Oct 14 18:43:43 Up

   [...Output truncated...]

  Created: Thu Oct 14 16:04:33 2004

Total 1 displayed, Up 0, Down 1

Egress LSP: 0 sessions

Total 0 displayed, Up 0, Down 0

Transit LSP: 0 sessions

Total 0 displayed, Up 0, Down 0

What It Means

The sample output from ingress router R1 shows that an MPLS label allocation failure occurred and the Constrained Shortest Path First (CSPF) algorithm failed, resulting in no route to destination 10.0.0.6 on R6.