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Re-optimization Time for Tunnel-TE in IOS XR 4.3.2

Unanswered Question
Oct 3rd, 2013
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We have configured the Tunnel-TE with explicit path options 1 & 2. When we generate a failure scenario in primary path, the traffic switches over to secondary immediately but on the failure restoration, the primary tunnel does not preempt. On further investigation, we found that default reoptimization time for TE Tunnel is 60 mins which is vey high for us.


The tunnel configuration is as below.


!

interface tunnel-te1

description "LOCA-LOCB"

ipv4 unnumbered Loopback10

autoroute announce

destination 10.220.7.3

path-option 1 explicit name PATH_Pri

path-option 2 explicit name PATH_Sec

!

explicit-path name PATH_Pri

index 10 next-address strict ipv4 unicast 10.220.37.82

!

explicit-path name PATH_Sec

index 10 next-address strict ipv4 unicast 10.220.37.6

index 20 next-address strict ipv4 unicast 10.220.37.86

index 30 next-address strict ipv4 unicast 10.220.37.9

!


While exploring through internet, I came across a forum which mentions 3 options for reoptimization but it is for IOS. The wording goes like...

  • Reoptimization causes a tunnel to be rerouted in the network onto the more  optimal path.
  • Three triggers can cause reoptimization of the TE tunnel so that it can be  rerouted to the better path.   
    • Periodic reoptimization - By default, the reoptimization of a TE tunnel  occurs with a frequency of one hour   
      • mpls traffic-eng reoptimize timers  frequency interval changes the periodic reoptimization  of a tunnel.
    • Event-driven reoptimization - mpls traffic-eng reoptimize  events link-up enables the reoptimization when a link becomes  operational for MPLS TE
      • By default, Cisco IOS does not trigger reoptimization when a link in the  network is available to TE again, either by configuration or because its state  becomes operational.
    • Manual reoptimization - mpls traffic-eng reoptimize forces the  immediate reoptimization of all the TE tunnels on the head end  router.

I would like to know that

1. Is there any specific requirement behind keeping the default (periodic) reoptimization timer to 60 mins?

2. I could not find the options for configuring 'Event Driven reoptimization' in IOS XR. How to get it?

3. What are best practice reoptimization timer to be used in the network?


P.S: We are running IOS-XR 4.3.2 on ASR 9000.


Regards,

Himanshu Bansal

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Overall Rating: 5 (2 ratings)
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GIANRICO FICHERA Thu, 06/22/2017 - 07:25
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   Hi, in global configuration mode you can configure the even drive optimization in this way:

RP/0/RSP0/CPU0:ASR9001(config)#mpls traffic-eng reoptimize events ?
link-up Trigger reoptimization on topology link-up events

   I hope this will be useful


Gianrico Fichera

nyandorot Thu, 07/27/2017 - 09:23
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@GIANRICO FICHERA  You are the man. Your reply works man. The only set back is that re-optimization is triggered by the RSVP (in your IGP) at the headend. Of which, this can take some time(seconds) depending on fast your IGP convergence to inform the headend that,"Oh man, that primary LSP that was down is now up, lets re-optimize and use it."

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