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 15 second(s).

   140 Sep 30 12:01:12 CSPF failed: no route toward 10.0.0.6[26 times]

   139 Sep 30 11:48:57 Deselected as active

   138 Sep 30 11:48:56 CSPF failed: no route toward 10.0.0.6

   137 Sep 30 11:48:56 Clear Call

   136 Sep 30 11:48:56 CSPF: link down/deleted 
10.1.36.1(R3.00/10.0.0.3)->10.1.36.2(R6.00/10.0.0.6)

135 Sep 30 11:48:56 ResvTear received

   134 Sep 30 11:48:56 Down

   133 Sep 30 11:48:56 CSPF failed: no route toward 10.0.0.6

   132 Sep 30 11:48:56 10.1.13.2: No Route toward dest

   [...Output truncated...]

  Created: Sat Jul 10 18:18:44 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 the LSPs within which it participates. The ingress LSP is down, without a path from R1 to R6. Because a reverse LSP is configured in the network shown in Figure 13, we would expect an egress LSP session to be up. However, R1 does not have any egress LSPs, indicating that the LSP from R6 to R1 is not functioning.