In Example: configuring a Level 1 area, ALA-A, ALA-B, and ALA-C are configured as Level 1 systems. Level 1 systems communicate with other Level 1 systems in the same area. In this example, ALA-A is modified to set the level capability to Level 1/2. Now, the Level 1 systems in the area with NET 47.0001 forward PDUs to ALA-A for destinations that are not in the local area.
The following figure shows the configuration of Level 1/2 area.
Figure: Configuring a Level 1/2 area
Example: Command usage to configure a Level 1/2 system
A:ALA-A>config>router# isis
A:ALA-A>config>router>isis# level-capability level-1/2