Users Guide
Version Description
8.3.19.0 Introduced on the S4820T.
8.3.11.1 Introduced on the Z9000.
8.3.12.0 Introduced on the S4810.
7.8.1.0 Added support for multi-topology ISIS.
7.5.1.0 Added support for SPF Throttling Enhancement.
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 rst 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 specied (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).
Intermediate System to Intermediate System (IS-IS)
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