Setting the SPF Calculation Interval
Context
A network change always triggers IS-IS to perform SPF calculation. Frequent SPF calculation will consume excessive CPU resources, affecting services.
To solve this problem, configure an intelligent timer to control the interval for SPF calculation. For example, to speed up IS-IS route convergence, set the interval for SPF calculation to a small value and set the interval to a large value after the IS-IS network becomes stable.
Procedure
- Run system-view
The system view is displayed.
- Run isis [ process-id ]
The IS-IS view is displayed.
- Run timer spf max-interval [ init-interval [ incr-interval ] ]
The SPF intelligent timer is configured.
By default, no SPF intelligent timer is configured and the maximum delay in SPF calculation is 5 seconds.
The delay for SPF calculation is described as follows:- The delay for the first SPF calculation is init-interval; the delay for the second SPF calculation is incr-interval. From the third time on, the delay for SPF calculation doubles each time until the delay reaches max-interval.
- If incr-interval is not specified, the delay for SPF calculation for the first time is init-interval. From the second time on, the delay is max-interval.
- When only max-interval is specified, the intelligent timer functions as an ordinary one-time triggering timer.
- Run suppress-flapping route-calculate timer delay-interval
A period is specified for the device to delay route calculation when the device receives an LSP during route flapping.
By default, if the device receives an LSP during route flapping, it delays route calculation for 10s.
- Run timer purge-zero-lsp route-calculate-delay delay-interval
A period is specified for the device to delay route calculation when the device receives a purge LSP.
By default, if the device receives a purge LSP, it delays route calculation for 10s.
- Run commit
The configuration is committed.