Supported Platforms
Related Documentation
- ACX, J, M, MX, PTX, QFX, SRX, T Series
- Example: Configuring Link and Node Protection for IS-IS Routes
spf-options (Protocols IS-IS)
Syntax
Hierarchy Level
Release Information
Statement introduced in Junos OS Release 8.5.
Statement introduced in Junos OS Release 9.0 for EX Series switches.
Description
Configure options for running the shortest-path-first (SPF) algorithm.
Running the SPF algorithm is usually the beginning of a series of larger system-wide events. For example, the SPF algorithm can lead to interior gateway protocol (IGP) prefix changes, which then lead to BGP nexthop resolution changes. Consider what happens if there are rapid link changes in the network. The local routing device can become overwhelmed. This is why it sometimes makes sense to throttle the scheduling of the SPF algorithm.
You can configure the following SPF options:
- The delay in the time between the detection of a topology change and when the SPF algorithm actually runs.
- The maximum number of times that the SPF algorithm can run in succession before the hold-down timer begins.
- The time to hold down, or wait, before running another SPF calculation after the SPF algorithm has run in succession the configured maximum number of times.
If the network stabilizes during the hold-down period and the SPF algorithm does not need to run again, the system reverts to the configured values for the delay and rapid-runs statements.
Options
delay milliseconds—Time interval between the detection of a topology change and when the SPF algorithm runs.
Range: 50 through 1000 milliseconds
Default: 200 milliseconds
holddown milliseconds—Time interval to hold down, or wait before a subsequent SPF algorithm runs after the SPF algorithm has run the configured maximum number of times in succession.
Range: 2000 through 10,000 milliseconds
Default: 5000 milliseconds
rapid-runs number—Maximum number of times the SPF algorithm can run in succession. After the maximum is reached, the holddown interval begins.
Range: 1 through 5
Default: 3
Required Privilege Level
routing—To view this statement in the configuration.
routing-control—To add this statement to the configuration.
Related Documentation
- ACX, J, M, MX, PTX, QFX, SRX, T Series
- Example: Configuring Link and Node Protection for IS-IS Routes
Published: 2013-04-03
Supported Platforms
Related Documentation
- ACX, J, M, MX, PTX, QFX, SRX, T Series
- Example: Configuring Link and Node Protection for IS-IS Routes
