Discussion

Transit LSP: 0 sessions
Total 0 displayed, Up 0, Down 0
This output correctly shows the one LSP we have configured.
For the three routers in the LSP, the show mpls lsp output differs slightly. The P column
for R1, the ingress router, contains an asterisk to indicate that LSP R1-to-R6 is
the primary LSP between the two routers. The output on the transit and egress routers
shows information about the RSVP reservation style and label values.
The command output for the transit router shows that received packets have a label
value of 103488 and it uses a label value of 3 on the record for outgoing packets. A
label value of 3 is one of the reserved values, used to request that the downstream
router pop the label. The transit router is the penultimate-hop router, and the egress
router has advertised a label value of 3 to R3 so that it performs penultimate-hop
popping to remove the top label on the stack before forwarding packets to R6.
The Rt column in the output on all three routers shows the number of active prefixes
installed in the routing table as a result of the RSVP session. Recipe 14.7 explains
how to view these routes.
The extensive version of the show mpls lsp command provides additional information
about the LSP, including a log of the LSP’s history:
aviva@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)
10.1.13.2 S 10.1.36.2 S
Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt):
10.1.13.2 10.1.36.2
5 Oct 4 13:31:06 Selected as active path
4 Oct 4 13:31:06 Record Route: 10.1.13.2 10.1.36.2
3 Oct 4 13:31:06 Up
2 Oct 4 13:31:06 Originate Call
1 Oct 4 13:31:06 CSPF: computation result accepted
Created: Tue Oct 4 13:31:05 2005
Total 1 displayed, Up 1, Down 0
This command works only on the ingress router because this router is responsible for
establishing and maintaining the LSP. The transit and egress routers have no details
about the LSP’s state. The first line of the output confirms what we already know
about the LSP: that it is named R1-to-R6, runs from 10.0.0.1 to 10.0.0.6, and is up.
The highlighted lines show the history of the LSP, from most current to oldest events.
The last line in the log tells you that the LSP was created at 13:31:05. RSVP used
CSPF to determine a path for the LSP (this is the default JUNOS RSVP behavior), and
508 | Chapter 14: MPLS
This is the Title of the Book, eMatter Edition
Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.