Technical Documentation

Routing Loop Detected Event

LSP Event

Routing loop detected

Sample Output

user@R1> show mpls lsp extensive
[...Output truncated...]
  From:, State: Dn, ActiveRoute: 0, LSPname: R1-to-R6
  ActivePath: (none)
  LoadBalance: Random
  Encoding type: Packet, Switching type: Packet, GPID: IPv4
  Primary   to-R6            State: Dn, No-decrement-ttl
   10 Jan 21 14:40:19 Routing loop detected
    9 Jan 21 14:40:19 Originate Call
    8 Jan 21 14:40:19 Clear Call
    7 Jan 21 14:40:16 Routing loop detected
    6 Jan 21 14:40:16 Clear Call
[...Output truncated...]


This LSP error event indicates that the RSVP message has looped. The IP address of the router that detected the loop precedes the LSP event.


The LSP error event is generated as part of a PathErr or ResvErr RSVP message when the packet goes through a router that is already listed in the Record Route Object (RRO). The RRO keeps a record of every address that the RSVP Path or Resv message transits.


Examine the strict hop addresses or examine the path in the ERO to determine the cause of the loop.

Published: 2010-01-30