Setting an Interval for Receiving LSAs

Context

OSPF stipulates that LSAs are received at an interval of 1s to prevent network connections or frequent route flapping from consuming excessive network bandwidth or device resources.

On a stable network where routes need to converge fast, you can set the LSA receipt interval to 0s so that the topology or route changes can be immediately advertised over the network through LSAs, thereby speeding up route convergence.

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 milliseconds.
- The parameter intelligent-timer indicates that an intelligent timer is used to set the interval for receiving Router-LSAs and 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.
By default, an intelligent timer is enabled. After an intelligent timer is enabled, the default maximum interval for receiving LSAs is 1000 ms, the default initial interval is 500 ms, and the default hold interval is 500 ms. The mechanism of the intelligent timer is as follows:
1. The initial interval for receiving LSAs is specified by start-interval.
2. The interval for the nth (n ≥ 2) LSA receipt is equal to hold-interval x 2^(n-2).
3. When the interval specified by hold-interval x 2^(n-2) reaches the maximum interval specified by max-interval, the maximum interval is used for the subsequent three LSA receipts. Then, OSPF goes back to step 3.a and receives LSAs at the initial interval specified by start-interval.