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To understand how preemption works, set up LSPs sequentially and observe how<br />

they are established. First, set up the lowest-priority LSP, R1-to-R5-low:<br />

[edit protocols mpls]<br />

aviva@R1# set label-switched-path R1-to-R5-low to 10.0.0.5<br />

aviva@R1# set label-switched-path R1-to-R5-low bandwidth 80m<br />

aviva@R1# set label-switched-path R1-to-R5-low to priority 7 7<br />

Because this is the first and only LSP on the ingress router, you expect RSVP to set it<br />

up even though it has the lowest setup priority. Look at the LSP to check that RSVP<br />

has set it up:<br />

aviva@R7# show mpls lsp<br />

Ingress LSP: 1 sessions<br />

To From State Rt ActivePath P LSPname<br />

10.0.0.5 10.0.0.1 Up 0 * R1-to-R5-low<br />

Total 1 displayed, Up 1, Down 0<br />

The State column confirms that the LSP is up. Then check that RSVP has reserved<br />

the requested bandwidth for the LSP:<br />

aviva@R7# show rsvp interface<br />

RSVP interface: 2 active<br />

Active Subscr- Static Available Reserved Highwater<br />

Interface State resv iption BW BW BW mark<br />

so-0/0/0.0 Up 1 100% 155.52Mbps 75.52Mbps 80Mbps 80Mbps<br />

so-0/0/2.0 Up 0 100% 155.52Mbps 155.52Mbps 0bps 100Mbps<br />

You see that RSVP has reserved 80 Mbps on the so-0/0/0 interface for this LSP.<br />

Finally, look at the details about the LSP:<br />

aviva@R7# show mpls lsp ingress extensive<br />

Ingress LSP: 1 sessions<br />

10.0.0.5<br />

From: 10.0.0.1, State: Up, ActiveRoute: 0, LSPname: R1-to-R5-low<br />

ActivePath: (primary)<br />

LoadBalance: Random<br />

Encoding type: Packet, Switching type: Packet, GPID: IPv4<br />

*Primary<br />

State: Up<br />

Priorities: 7 7<br />

Bandwidth: 80Mbps<br />

SmartOptimizeTimer: 180<br />

Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 30)<br />

10.1.12.2 S 10.1.26.2 S 10.1.56.1 S<br />

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

10.1.12.2 10.1.26.2 10.1.56.1<br />

10 Oct 14 10:39:39 Record Route: 10.1.12.2 10.1.26.2 10.1.56.1<br />

9 Oct 14 10:39:39 Up<br />

8 Oct 14 10:39:39 Originate Call<br />

...<br />

Created: Fri Oct 14 10:35:55 2005<br />

Total 1 displayed, Up 1, Down 0<br />

This output confirms that the LSP is up and shows the configured priority values and<br />

bandwidth request.<br />

This is the Title of the Book, eMatter Edition<br />

Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.<br />

Prioritizing LSPs | 539

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