Setting the Interval for the SPF Calculation

By setting the interval for the SPF calculation, you can save resources consumed by frequent network changes.

Context

When the OSPF LSDB changes, the shortest path needs to be recalculated. If a network changes frequently, the shortest path is calculated accordingly, which consumes a large number of system resources degrades system performance. By configuring an intelligent timer and a proper 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 [ conservative ] | millisecond interval2 }
The interval for the SPF calculation is set.
If an intelligent timer is used, 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 × 2^(n-2).
3. When the interval specified in hold-interval × 2^(n-2) reaches the maximum interval specified in max-interval, OSPF 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.
Run commit
The configuration is committed.