Reference Guide

To restore default values, use the no spf-interval [level-l | level-2]
interval seconds [initial_wait_interval seconds
[second_wait_interval seconds]] command.
Parameters
level-l (OPTIONAL) Enter the keyword level-1 to apply the
configuration to Level-1 SPF calculations.
level-2 (OPTIONAL) Enter the keyword level-2 to apply the
configuration to Level-2 SPF calculations.
interval
seconds
Enter the maximum number of seconds between SPF
calculations. The range is 0 to 120 seconds. The default is 10
seconds.
initial_wait_inte
rval seconds
(OPTIONAL) Enter the initial wait time, in seconds, before
running the first SPF calculations. The range is 0 to 120
seconds. The default is 5 seconds.
second_wait_i
nterval seconds
(OPTIONAL) Enter the wait interval, in seconds, between the
first and second SPF calculations. The range is 0 to 120
seconds. The default is 5 seconds.
Defaults Refer to Parameters.
Command
Modes
• ROUTER ISIS (for IPv4)
• CONFIGURATION-ROUTER-ISIS-ADDRESS-FAMILY-IPV6 (for IPv6)
Command
History
Version 9.0(1.3) Introduced on the S5000.
Usage
Information
This command spf-interval in CONFIG-ROUTER-ISIS-AF-IPV6 mode is used
for IPv6 Multi-Topology route computation only. If using Single Topology mode,
use the spf-interval command in CONFIG-ROUTER-ISIS mode for both IPv4
and IPv6 route computations.
SPF throttling slows down the frequency at which route calculations are performed
during network instability. Even though throttling route calculations slows down
network convergence, not throttling can result in a network not functioning as
expected. If network topology is unstable, throttling slows down the scheduling of
route calculations until the topology regains its stability.
The first route calculation is controlled by the initial wait interval and the second
calculation is controlled by the second wait interval. Each subsequent wait interval
is twice as long as the previous one until the wait interval reaches the maximum
wait time specified (interval seconds). After the network calms down and there
are no triggers for two times the maximum interval, fast behavior is restored (the
initial wait time).
858
Intermediate System to Intermediate System (IS-IS)