Setting the Interval for the SPF Calculation
Context
When the OSPF LSDB changes, the shortest path needs to be recalculated. If a network changes frequently and the shortest path is calculated continually, many system resources are consumed and thus system performance is degraded. By configuring an intelligent timer and setting a correct interval for the SPF calculation, you can prevent excessive system memory and bandwidth resources from being occupied.
Procedure
- Run system-view
The system view is displayed.
- Run ospf [ process-id ]
The OSPF process view is displayed.
- Run spf-schedule-interval { interval1 | intelligent-timer max-interval start-interval hold-interval | millisecond interval2 }
The interval for the SPF calculation is set.
- The parameter interval1 specifies the interval for the SPF calculation, in milliseconds.
- The parameter intelligent-timer indicates that the interval for the SPF calculation is set through an intelligent timer.
- The parameter max-interval specifies the maximum interval for the SPF calculation, in milliseconds.
- The parameter start-interval specifies the initial interval for the SPF calculation, in milliseconds.
- The parameter hold-interval specifies the hold interval for the SPF calculation, in milliseconds.
- The parameter millisecond interval2 specifies the interval for the SPF calculation, in milliseconds.
By default, an intelligent timer is enabled; the maximum interval for the SPF calculation is 10000 ms, the initial interval is 500 ms, and the hold interval is 1000 ms.
After an intelligent timer is enabled, the interval for the SPF calculation is as follows:
The initial interval for the SPF calculation is specified by the parameter start-interval.
The interval for the SPF calculation for the nth (n ≥ 2) time is equal to hold-interval x 2(n-2).
When the interval specified by hold-interval x 2(n-2) reaches the maximum interval specified by max-interval, OSPF performs the SPF calculation at the maximum interval for three consecutive times. Then, OSPF goes back to step 3.a and performs the SPF calculation at the initial interval specified by start-interval.
