Setting the Interval for Receiving LSAs
Context
In OSPF, the interval for receiving LSAs is defined as 1s. This aims to prevent network connections or frequent route flapping from consuming excessive network bandwidth or device resources.
On a stable network where routes need to fast converge, you can cancel the interval for receiving LSAs by setting the interval to 0s. In this manner, changes of the topology or the routes can be immediately advertised on the network through LSAs, thereby speeding up route convergence on the network.
Procedure
- Run system-view
The system view is displayed.
- Run ospf [ process-id ]
The OSPF process view is displayed.
- Run lsa-arrival-interval { interval | intelligent-timer max-interval start-interval hold-interval }
The interval for receiving LSAs is set.
- The parameter interval specifies the interval for receiving LSAs, in seconds.
- The parameter intelligent-timer indicates that an intelligent timer is used to set the interval for receiving router LSAs or network LSAs.
- The parameter max-interval specifies the maximum interval for receiving LSAs, in milliseconds.
- The parameter start-interval specifies the initial interval for receiving LSAs, in milliseconds.
- The parameter hold-interval specifies the hold interval for receiving LSAs, in milliseconds.
On a stable network that requires fast route convergence, you can change the interval at which LSAs are received to 0s. In this manner, the device can fast respond to topology or route changes, which speeds up route convergence.
By default, an intelligent timer is enabled. The interval for receiving LSAs is expressed in milliseconds. The maximum interval for updating LSAs is 1000 milliseconds (ms), the initial interval is 500 ms, and the Holdtime interval is 500 ms.
After an intelligent timer is enabled, the interval for receiving LSAs is as follows:- The initial interval for the SPF calculation is specified in start-interval.
- The interval for the SPF calculation for the nth (n≥2) time is equal to hold-interval × 2(n-2).
- When the interval specified in hold-interval × 2(n-2) reaches the maximum interval specified in max-interval, OSPF receives LSAs at the maximum interval for three consecutive times. Then, OSPF receives LSAs at the initial interval specified by start-interval.
- (Optional) Run lsa-arrival-interval suppress-flapping suppress-interval [ threshold threshold ]
The maximum LSA suppression period is configured.
If frequent LSA flapping occurs, the larger value between lsa-arrival-interval suppress-flapping and lsa-arrival-interval is used as the value of the suppression timer.
By default, if a device receives an LSA, it delays route calculation for 10s in route flapping scenarios.
- Run commit
The configuration is committed.