timer spf
Use timer spf to set the SPF computation timer parameters.
Use undo timer spf to restore the default.
Syntax
timer spf maximum-interval [ minimum-interval [ incremental-interval ] ]
undo timer spf
Default
The maximum interval is 5 seconds.
The minimum interval is 10 milliseconds.
The base number for the incremental interval is 10 milliseconds.
Views
SPBM view
Predefined user roles
network-admin
Parameters
maximum-interval: Specifies the maximum SPF computation interval in the range of 1 to 120 seconds.
minimum-interval: Specifies the minimum SPF computation interval in the range of 10 to 60000 milliseconds. This setting must be smaller than the maximum interval.
incremental-interval: Specifies the base number for the incremental interval, in the range of 10 to 60000 milliseconds. This setting must be smaller than the maximum interval.
Usage guidelines
The SPF calculation timer sets the delay between consecutive SPF calculations. You can increase the timer for ISIS-SPB to react quickly to topology changes, and decrease the timer to protect the CPU from frequent SPF calculations.
The SPF timer is an exponential generation timer. With this timer, ISIS-SPB quickly responds to the first events that trigger SPF calculation and then slows down to protect the CPU from frequent SPF calculations.
When the network is stable, the SPF calculation timer is set to the minimum interval for each SPF computation. When the network is unstable, the SPF calculation timer increments by incremental-interval×2n-2 (n is the number of calculations) for each SPF calculation until the maximum interval is reached. If an event triggers SPF calculation after the maximum interval is reached, the SPF calculation timer re-initiates with the minimum interval.
The network is considered unstable if the interval between consecutive SPF calculations is smaller than two times the maximum interval.
Examples
# Set the maximum SPF computation interval, the minimum SPF computation interval, and the base number for the incremental interval to 10 seconds, 100 milliseconds, and 300 milliseconds, respectively.
<Sysname> system-view [Sysname] spbm [Sysname-spbm] timer spf 10 100 300