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@ingress-router> show mpls lsp extensive

Sample Output

user@R1> show mpls lsp extensive

Ingress LSP: 1 sessions

10.0.0.6

  From: 10.0.0.1, State: Up, ActiveRoute: 1, LSPname: R1-to-R6

  ActivePath:  (primary)

  LoadBalance: Random

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

 *Primary                    State: Up

    Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 20)

 10.1.12.2 S 10.1.26.2 S 

    Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 
10=SoftPreempt):

          10.1.12.2 10.1.26.2

   99 Sep 18 14:19:04 CSPF: computation result accepted

   98 Sep 18 14:19:04 CSPF: link down/deleted 
10.1.13.1(R1.00/10.0.0.1)->10.1.13.2(R3.00/10.0.0.3)

   97 Sep 18 14:19:01 Record Route:  10.1.12.2 10.1.26.2

   96 Sep 18 14:19:01 Up

   95 Sep 18 14:19:01 Clear Call

   94 Sep 18 14:19:01 CSPF: computation result accepted

   93 Sep 18 14:19:01 MPLS label allocation failure

   92 Sep 18 14:19:01 Down

   91 Aug 17 12:22:52 Selected as active path

   90 Aug 17 12:22:52 Record Route:  10.1.13.2 10.1.36.2

   89 Aug 17 12:22:52 Up

   [...Output truncated...]

  Created: Sat Jul 10 18:18:44 2004

Total 1 displayed, Up 1, Down 0

Egress LSP: 1 sessions

10.0.0.1

  From: 10.0.0.6, LSPstate: Up, ActiveRoute: 0

  LSPname: R6-to-R1, LSPpath: Primary

  Suggested label received: -, Suggested label sent: -

  Recovery label received: -, Recovery label sent: -

  Resv style: 1 FF, Label in: 3, Label out: -

  Time left:  144, Since: Tue Aug 17 12:23:14 2004

  Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500

  Port number: sender 1 receiver 39024 protocol 0

  PATH rcvfrom: 10.1.15.2 (so-0/0/1.0) 67333 pkts

  Adspec: received MTU 1500 

  PATH sentto: localclient

  RESV rcvfrom: localclient 

  Record route: 10.1.56.2 10.1.15.2 <self>  

Total 1 displayed, Up 1, 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 the LSP is using an alternate path rather than the configured path. The configured path for the LSP is R1 through R3 to R6, and for the reverse LSP, R6 through R3 to R1. The alternate path used by the LSP is R1 through R2 to R6, and for the reverse LSP, R6 through R5 to R1.