isis hello-interval

Use this command to configure the IS-IS Hello Protocol Data Units (IIH) interval for the interface.


isis hello-interval {seconds | minimal} [level-1 | level-1-2 | level-2]
no isis hello-interval seconds [level-1 | level-1-2 | level-2]


seconds Specifies the number of seconds between IS-IS IIH PDUs on the interface. Valid values are 1 - 600. The default value is 10 seconds.
minimal Sets the hello interval such that the resulting hold time is 1 second.
level-1 (Optional) Specifies that the hello interval is applied to level 1 for the interface.
level-1-2 (Optional) Specifies that the hello interval is applied to both level 1 and level 2 for the interface (Default).
level-2 (Optional) Specifies that the IS-IS hello interval is applied to level 2 for the interface.


If an IS-IS level is not specified, the level type defaults to both level 1 and level 2.


Interface configuration.


The advertised holdtime in the hello packet is set to three times the hello interval seconds. The holdtime multiplier can be changed using isis hello-multiplier. Topological changes are detected faster with a smaller hello interval, but there is more routing traffic.

The “no” form of this command resets the hello interval to the default value of 10 seconds for the interface.


This example shows how to configure the IS-IS hello interval to 15 seconds:

System(rw-config)->interface vlan 100
System(rw-config-intf-vlan.0.100)->isis hello-interval 15