Enabling advertisement of a default route

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
   

3. Enter the address-family ipv6 unicast command to enable ISIS address-family IPv6 unicast configuration mode.
   

   device(config-isis-router)# address-family ipv6 unicast
   

4. Enter the default-information-originate command to enable the advertisement of a default route.
   

   device(config-router-isis-ipv6u)# default-information-originate
   

The following example enables the advertisement of a default route for the IS-IS IPv6 unicast address-family.

device# configure terminal
device(config)# router isis
device(config-isis-router)# address-family ipv6 unicast
device(config-router-isis-ipv6u)# default-information-originate