Enabling IS-IS globally

1. Enter the configure terminal command to access global configuration mode.
   

   device# configure terminal

2. Enter the router isis command to enter IS-IS router configuration mode and enable IS-IS on the device.
   

   device(config)# router isis
   ISIS: Please configure NET!
   

3. Enter the net command and specify a NSAP address to configure a NET for IS-IS.
   

   device(config-isis-router)# net 49.2211.0000.00bb.cccc.00
   

The following example enables IS-IS on a device.

device# configure terminal
device(config)# router isis
ISIS: Please configure NET!
device(config-isis-router)# net 49.2211.0000.00bb.cccc.00