SPF timers

The device uses an SPF delay timer and an SPF hold-time timer to calculate the shortest path for OSPFv2 routes. The values for both timers can be changed.

  • SPF delay: When the device receives a topology change, it waits before starting a Shortest Path First (SPF) calculation. By default, the device waits zero seconds. You can configure the SPF delay to a value from 0 through 65535 seconds. If you set the SPF delay to 0 seconds, the device immediately begins the SPF calculation after receiving a topology change.
  • SPF hold time: The device waits a specific amount of time between consecutive SPF calculations. By default, it waits zero seconds. You can configure the SPF hold time to a value from 0 through 65535 seconds. If you set the SPF hold time to 0 seconds, the device does not wait between consecutive SPF calculations.

You can set the SPF delay and hold time to lower values to cause the device to change to alternate paths more quickly if a route fails. Note that lower values for these parameters require more CPU processing time.

You can change one or both of the timers.

NOTE
If you want to change only one of the timers, for example, the SPF delay timer, you must specify the new value for this timer as well as the current value of the SPF hold timer, which you want to retain. The device does not accept only one timer value.
NOTE
If you configure SPF timers between 0 through 100, they default to 0.
Parent topic: OSPFv2