How to preempt MPLS TE FRR

[Istvan kelemen]

Hi,

I have an Explicit Path configured on a tunnel as 1 and a dynamic path as 2.

If a link fails in the core FRR fails over, then after a while the tunnel takes teh dynamic path. However when the link recovers the tunnel stays on the dynamic path.

My question is: how can i force to take the explicit path again?

R1#show mpls traffic-eng tunnels tunnel 1

Name: R1_t1                               (Tunnel1) Destination: 2.2.2.2
  Status:
    Admin: up         Oper: up     Path: valid       Signalling: connected
    path option 2, type dynamic (Basis for Setup, path weight 3)
    path option 1, type explicit 1

  Config Parameters:
    Bandwidth: 0        kbps (Global)  Priority: 7  7   Affinity: 0x0/0xFFFF
    Metric Type: TE (default)
    AutoRoute: disabled LockDown: disabled Loadshare: 0 [0] bw-based
    auto-bw: disabled
  Active Path Option Parameters:
    State: dynamic path option 2 is active
    BandwidthOverride: disabled  LockDown: disabled  Verbatim: disabled

  InLabel  :  -
  OutLabel : FastEthernet0/1, 28
  Next Hop : 10.15.0.5
  RSVP Signalling Info:
       Src 1.1.1.1, Dst 2.2.2.2, Tun_Id 1, Tun_Instance 32
    RSVP Path Info:
      My Address: 10.15.0.1
      Explicit Route: 10.15.0.5 10.56.0.5 10.56.0.6 10.26.0.6
                      10.26.0.2 2.2.2.2
      Record   Route:   NONE
      Tspec: ave rate=0 kbits, burst=1000 bytes, peak rate=0 kbits
    RSVP Resv Info:
      Record   Route:  5.5.5.5(28) 6.6.6.6(33)
                       2.2.2.2(3)
      Fspec: ave rate=0 kbits, burst=1000 bytes, peak rate=0 kbits
  Shortest Unconstrained Path Info:
    Path Weight: 3 (TE)
    Explicit Route: 10.15.0.1 10.15.0.5 10.56.0.5 10.56.0.6
                    10.26.0.6 10.26.0.2 2.2.2.2
  History:
    Tunnel:
      Time since created: 1 hours, 48 minutes
      Time since path change: 55 seconds
      Number of LSP IDs (Tun_Instances) used: 32
    Current LSP: [ID: 32]
      Uptime: 58 seconds
      Selection: reoptimization
    Prior LSP: [ID: 30]
      ID: path option 1 [30]
      Removal Trigger: re-route path error
      Last Error: RSVP:: Path Error from 10.13.0.3: Notify: Tunnel locally repaired (flags 0)

Thx!

[Nagendra Kumar Nainar]

Hi,

By default, the re-optimization is around 1 hour. You can use the below command to speed up the re-optimization,

mpls traffic-eng reoptimize timers frequence <seconds>

With this command, the router after the seconds mentioned will check for better path for existing LSP (to see if primary path option is available) and use it if available.

-Nagendra

[kunapuri]

There are couple of options,

Manual re optimization with mpls traffic 

R11#mpls traffic-eng reoptimize tunnel 1 in the exec mode

or event Driven re optimization  with “ mpls traffic-eng reoptimize events link-up“  command in IOS

Not sure if you require the solution by now , Let me know incase you have any further query on MPLS TE

[ปลาวาฬทราย RMUTT CPE IX]

By default, the re-optimization is around 1 hour.

I tried in real XR network, it less than 30 minutes. Do you have any document to support?

But I found on IOS like you said.

http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/TE_1208S.html#wp27138

Thank you very much.