Modifying router-level parameters

When IS-IS is enabled, the default level-capability is Level 1/2. This means that the router operates with both Level 1 and Level 2 routing capabilities. To change the default value in order for the router to operate as a Level 1 router or a Level 2 router, you must explicitly modify the level value.

If the level is modified, the protocol shuts down and restarts. Doing this can affect adjacencies and routes.

The level-capability value can be configured on the global level and also on the interface level. The level-capability value determines which level values can be assigned on the router level or on an interface-basis.

In order for the router to operate as a Level 1 only router or as a Level 2 only router, you must explicitly specify the level number value:

Select level-1 to route only within an area.
Select level-2 to route to destinations outside an area, toward other eligible Level 2 routers.

Example

The following shows the command usage to configure the router level.

config>router# isis
    level-capability {level-1|level-2|level-1/2}
    level {1|2}

config>router# isis
    config>router>isis# level-capability 1/2
    config>router>isis# level 2

Example: Configuration output

A:ALA-A>config>router>isis# info
#------------------------------------------
echo "ISIS"
#------------------------------------------

level-capability level-1/2
level 2

----------------------------------------------
A:ALA-A>config>router>isis#