Administrator Guide

Command History
This guide is platform-specific. For command information about other platforms, refer to the relevant Dell
Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version Description
9.9(0.0) Introduced on the C9010.
9.5(0.1) Introduced on the Z9500.
9.0.2.0 Introduced on the S6000.
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 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).
Intermediate System to Intermediate System (IS-IS) 819