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 verify that the LSP is up, enter some or all of the following commands from the ingress router:

user@host> show mpls lsp

user@host> show mpls lsp extensive

user@host> show mpls lsp name name

user@host> show mpls lsp name name extensive

Sample Output 1

user@R1> show mpls lsp

Ingress LSP: 1 sessions

To              From            State Rt ActivePath       P     LSPname

10.0.0.6        10.0.0.1        Dn     0 -                      R1-to-R6

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

user@R3> show mpls lsp

Ingress LSP: 0 sessions

Total 0 displayed, Up 0, Down 0

Egress LSP: 0 sessions

Total 0 displayed, Up 0, Down 0

Transit LSP: 0 sessions

Total 0 displayed, Up 0, Down 0

user@R6> show mpls lsp

Ingress LSP: 1 sessions

To              From            State Rt ActivePath       P     LSPname

10.0.0.1        10.0.0.6        Dn     0 -                      R6-to-R1

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

Sample Output 2

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 22 second(s).

    1 Nov  2 14:43:38 CSPF failed: no route toward 10.0.0.6[175 times]

  Created: Tue Nov  2 13:18:39 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

user@R3> show mpls lsp extensive

user@R3> show mpls lsp extensive 

Ingress LSP: 0 sessions

Total 0 displayed, Up 0, Down 0

Egress LSP: 0 sessions

Total 0 displayed, Up 0, Down 0

Transit LSP: 0 sessions

Total 0 displayed, Up 0, Down 0

user@R6> show mpls lsp extensive

Ingress LSP: 1 sessions

10.0.0.1

  From: 10.0.0.6, State: Dn, ActiveRoute: 0, LSPname: R6-to-R1

  ActivePath: (none)

  LoadBalance: Random

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

  Primary                    State: Dn

    Will be enqueued for recomputation in 13 second(s).

    1 Nov  2 14:38:12 CSPF failed: no route toward 10.0.0.1[177 times]

  Created: Tue Nov  2 13:12:22 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

Sample Output 3

user@R1> show mpls lsp name R1-to-R6

Ingress LSP: 1 sessions

To              From            State Rt ActivePath       P     LSPname

10.0.0.6        10.0.0.1        Dn     0 -                      R1-to-R6

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

Sample Output 4

user@R1> show mpls lsp name R1-to-R6 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 10 second(s).

    1 Nov  2 14:51:53 CSPF failed: no route toward 10.0.0.6[192 times]

  Created: Tue Nov  2 13:18:39 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

Sample Output 1 shows a brief description of the state of the LSP for the ingress, transit, and egress routers. Output from ingress router R1 and egress router R6 shows that both LSPs are down, R1-to-R6 and R6-toR1. With the configured LSPs on R1 and R6, we would expect egress LSP sessions on both R1 and R6. In addition, transit router R3 has no transit sessions.

Sample Output 2 shows all information about the LSPs, including all past state history and the reason why an LSP failed. Output from R1 and R6 indicates that there is no route to the destination because the Constrained Shortest Path First (CSPF) algorithm failed.

Sample Outputs 3 and 4 show examples of the output for the show mpls lsp name command with the extensive option. In this instance, the output is very similar to the show mpls lsp command because only one LSP is configured in the example network in Figure 22. However, in a large network with many LSPs configured, the results would be quite different between the two commands.