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Hierarchy Level

Release Information

Statement introduced before Junos OS Release 7.4.

Statement introduced in Junos OS Release 12.3X50 for the QFX Series.


Enable the smart optimization timer. When you enable the smart optimization timer on a router, the Junos OS operates on the assumption that the original LSP path is preferable to any alternate or secondary path. When you enable the smart optimization timer and an LSP fails and its traffic is switched to an alternate path, the smart optimization timer starts and waits 3 minutes (this time is configurable). After 3 minutes have passed, the LSP is switched back to the original path. If the original path fails again and the LSP is switched to an alternate path again, the router waits 1 hour before attempting to switch the LSP back to its original path.

If you want to disable the smart optimizer, you can set it to zero. The smart-optimize-timer value in seconds indicates the time before which the LSP is switched back to its primary path in case the primary path becomes available. Otherwise, the time to wait is controlled by the optimize-timer, which is usually set to a high value. Some ISPs have the optimize-timer set to once a day. Sometimes after the smart optimizer causes the LSP to be placed back on its primary path, the primary path goes down again within 60 minutes. When this happens, the smart-optimize-timer is disabled automatically, and the optimize-timer (regular path optimization) goes into effect. This is to protect against a flapping link being used.


The smart optimization timer is enabled by default.


seconds—(Optional) Specify the number of seconds to wait before switching an LSP back to its original path. If you do not specify the number of seconds, the default value is used.

Range: 0 through 65,535 seconds

Default: 180 seconds

Required Privilege Level

routing—To view this statement in the configuration.

routing-control—To add this statement to the configuration.