Configuring the SPF Timer

By setting the interval for Shortest Path First (SPF) calculation, you can reduce resource consumption caused by frequent network changes.

Context

Whenever the Link-state Database (LSDB) of OSPFv3 changes, the shortest path should be recalculated. Calculating the shortest path each time the LSDB changes consumes enormous resources and lowers the efficiency of a router.

Adjusting the SPF delay and hold interval can suppress frequent network changes to avoid resource consumption.

Procedure

Configure an SPF normal timer.
1. Run system-view
  The system view is displayed.
2. Run ospfv3 [ process-id ]
  The OSPFv3 view is displayed.
3. Run spf timers delay-interval hold-interval
  An SPF normal timer is configured.
4. Run commit
  The configuration is committed.
Configure an SPF intelligent timer.
1. Run system-view
  The system view is displayed.
2. Run ospfv3 [ process-id ]
  The OSPFv3 view is displayed.
3. Run spf-schedule-interval { delay-interval hold-interval | intelligent-timer max-interval start-interval hold-interval-1 | millisecond interval2 }
  An SPF intelligent timer is configured.
  The interval for the SPF calculation is as follows:
  1. The initial interval for the SPF calculation is specified in start-interval.
  2. The interval for the SPF calculation for the nth (n≥2) time is equal to hold-interval-1 × 2^(n-2).
  3. When the interval specified in hold-interval-1 × 2^(n-2) reaches the maximum interval specified in max-interval, OSPFv3 performs the SPF calculation at the maximum interval until no SPF calculation is performed within max-interval. After the maximum interval elapses, the calculation mechanism goes back to step 1.
  4. If no flapping occurs within the interval of max-interval that starts upon the end of the previous SPF calculation, the intelligent timer exits.
  5. If no flapping occurs in the previous interval and flapping occurs in the current interval, SPF calculation is delayed for a period of the start-interval. After the SPF calculation is complete, the current interval is used for the next SPF calculation.
  An SPF normal timer and an SPF intelligent timer are mutually exclusive.
4. Run commit
  The configuration is committed.