Routers send hello packets at a fixed interval on all interfaces to establish and maintain neighbor relationships. This interval is advertised in the hello interval field in the hello packet. By default, a designated intersystem (DIS) router sends hello packets every 3 seconds, and a non-DIS router sends hello packets every 9 seconds.
To modify how often the router sends hello packets out of an interface, include the hello-interval statement:
-
hello-interval seconds;
The hello interval range is from 1 through 20,000 seconds.
You can send out hello packets in sub-second intervals. To send out hello packets every 333 milliseconds, set the hello-interval value to 1.
For a list of hierarchy levels at which you can configure this statement, see the statement summary section for this statement.