3com S7906E Guide De Référence
1-62
undo timer spf
View
IS-IS view
Default Level
2: System level
Parameters
maximum-interval: Maximum SPF calculation interval in seconds, ranging from 1 to 120.
initial-interval: Wait interval before the first SPF calculation, in milliseconds, ranging from 10 to 60000.
second-interval: Wait interval before the second SPF calculation, in milliseconds, ranging from 10 to
60000.
Description
Use the timer spf command to set the SPF calculation interval.
Use the undo timer spf command to restore the default.
The default IS-IS SPF calculation interval is 10 seconds.
Note that:
1) If only the maximum interval is specified, IS-IS waits the maximum interval before performing the
SPF calculation.
2) If both the maximum and initial intervals are specified:
z
IS-IS waits the initial interval before performing the first SPF calculation.
z
When SPF calculation triggers occur at intervals shorter than the maximum interval, the topology is
considered unstable and IS-IS waits the maximum interval before performing the SPF calculation
unitl the topology is stable.
3) If maximum-interval, initial-interval, and second-interval are specified:
z
IS-IS waits the initial interval before performing the first SPF calculation.
z
When SPF calculation triggers occur at intervals shorter than the maximum interval, the topology is
considered unstable, IS-IS will wait the second-interval before performing the second SPF
calculation and penalty is applied on the wait interval for the next SPF calculation. That is, for each
subsequent trigger, the wait interval before SPF calculation will be two times the previous wait
interval until the maximum interval is reached.
z
After the network topology becomes stable; that is, triggers occur at intervals greater than the
maximum interval, the wait interval before SPF calculation is restored to the initial interval.
Examples
# Configure the maximum SPF calculation interval as 10 seconds, the wait interval before the first SPF
calculation as 100 milliseconds, and the wait interval before the second SPF calculation as 200
milliseconds.
<Sysname> system-view
[Sysname] isis
[Sysname-isis-1]timer spf 10 100 200
# Configure the maximum SPF calculation interval as 15 seconds.
<Sysname> system-view
[Sysname] isis