Technical Documentation

Session Preempted Event

LSP Event

Session preempted

Sample Output 1

user@R1> show mpls lsp extensive
[...Output truncated...]
    21 Dec 28 13:46:39 ResvTear received
   20 Dec 28 13:46:39 Down
   19 Dec 28 13:46:39   Session preempted
   18 Dec 28 13:42:07 Selected as active path
   17 Dec 28 13:42:07 Record Route:
[...Output truncated...]

Sample Output 2

user@R1> show mpls lsp extensive
[...Output truncated...]
   66 Jan  5 09:58:33 CSPF failed: no route toward
   65 Jan  5 09:58:33 Clear Call
   64 Jan  5 09:58:33  Session preempted
   63 Jan  5 09:58:33 Down
   62 Jan  5 09:58:32  CSPF failed
 : no route toward[2 times]
61 Jan  5 09:57:55 Explicit Route: wrong delivery
   60 Jan  5 09:57:34 CSPF failed: no route toward[2 times]
   59 Jan  5 09:57:28 CSPF: link down/deleted>
[...Output truncated...]


This LSP event indicates that the LSP session was taken over. Sample Output 1 shows the IP address ( included with the event, indicating the IP address of the router that sent the message. Sample Output 2 does not include an IP address, indicating that the message originated on the ingress router.


The state of the network might have changed, as shown in Sample Output 1, or an LSP with a higher priority might be using the bandwidth of the LSP.


Refer to the events preceding this event in the history log for more information on what might have caused the preemption. For example, in line 62, the CSPF failed message may indicate that you specified a disable constrained-path (no-cspf) LSP and an explicit route address that is strict and not directly connected. Additionally, the egress router might have changed its configuration, making the destination address unreachable.

Published: 2010-01-30