Configuring the Interval for SPF Calculation

Through the configuration of the interval for SPF calculation, the influence resulting from network changes can be restrained.

Context

When the OSPF LSDB changes, the shortest path need be recalculated. Frequent network changes occupy many system resources and affect the efficiency of routers. You can configure an intelligent timer and rationally set the interval for the SPF calculation to avoid excessive router memory and bandwidth resources from being occupied.

Adjusting the SPF calculation interval, however, can restrain the resource consumption due to frequent network changes.

Procedure

Access the system view.
system-view
Access the OSPF process view.
ospf [ process-id ]
Set an interval for SPF calculation.
spf-schedule-interval { interval1 | intelligent-timer max-interval start-interval hold-interval | millisecond interval2 }

By default, the intelligent timer is enabled. The interval for the SPF calculation is expressed in milliseconds. The maximum interval for the SPF calculation is 10000 ms, the initial interval is 500 ms, and the Holdtime interval is 1000 ms. After an intelligent timer is enabled, the interval for the SPF calculation is as follows:
1. The initial interval for the SPF calculation is specified by the parameter start-interval.
2. The interval for the SPF calculation for the nth (n≥2) time is equal to hold-interval × 2(n-1).
3. When the interval specified by hold-interval × 2(n-1) reaches the maximum interval specified by max-interval, OSPF performs the SPF calculation at the maximum interval for three consecutive times. Then, go back to Step 3.a, and OSPF performs the SPF calculation at the initial interval specified by start-interval.