set protocols ospf timers throttle spf

Run the command set protocols ospf timers throttle spf to set the initial delay, the initial hold time and the maximum hold time between when the SPF is calculated and the event which triggered the calculation. These timers prevent the system from overburdening the CPU with frequent SPF calculations. Optional parameter instance-id can be included to specify the OSPFv2 multi-instance ID. The optional parameter vrf can be used to specify the name of the VRF for this configuration to take effect on. If the VRF name is not specified, the command takes effect on OSPF for the default VRF.

Run the command delete protocols ospf timers throttle spf to delete this configuration.

Command Syntax

set protocols ospf [instance-id <instance-id> | vrf <vrf-name>] timers throttle spf {delay<delay> | initial-holdtime<initial-hold-time> | maximum-holdtime<max-hold-time>}

delete protocols ospf [instance-id <instance-id> | vrf <vrf-name>] timers throttle spf {<delay> | <initial-hold-time> | <max-hold-time>}

Parameter

Usage Guidelines

These three parameters are important fine tuning tools for OSPF. These timers are introduced to delay starting SFP calculations when a SPF-triggering event occurs. Frequent SPF calculations may incur heavy burden on the device resources such as CPU especially in large OSPF networks. The delay parameter specifies the delay in SPF calculation. This delay also applies to events occurring outside the hold-time of the previous SPF calculation. Two consecutive SPF calculations are always delayed by at least hold-time delay in milliseconds. The hold-time is initially set to the initial hold-time but its value is flexible and may be changed. If an event occurs within the hold-time of the previous SPF calculation, it results in increasing the hold-time by initial hold-time. If the flexible hold-time expires and no SPF triggering event occurs, the hold-time is reset to initial hold-time. 

The example below sets the initial delay to 20ms, initial hold-time to 50ms and maximum hold-time to 5 seconds. This means that there will be a delay of 20ms between an SPF-triggering event and the commencement of the actual SPF calculation. The delay between two consecutive SPF calculations will be between 50ms and 5 seconds. If an SPF-triggering event occurs between the hold-time of the previous SPF calculation, the hold-time is increased by 50ms.

Example

•  Configure OSPF SPF timers of initial delay time, minimum hold time and maximum hold time to 20, 50 and 5000ms respectively for OSPF instance ID 1.

admin@XorPlus# set protocols ospf instance-id 1 timers throttle spf delay 20 
admin@XorPlus# set protocols ospf instance-id 1 timers throttle spf initial-holdtime 50
admin@XorPlus# set protocols ospf instance-id 1 timers throttle spf maximum-holdtime 5000
admin@Xorplus# commit