Enabling IPv6 IS-IS MT

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 multi-topology command with the transition parameter to enable IPv6 IS-IS MT with transition support.
   

   device(config-router-isis-ipv6u)# multi-topology transition
   

The following example enables IPv6 IS-IS MT with transition support.

device# configure terminal
device(config)# router isis
device(config-isis-router)# address-family ipv6 unicast
device(config-router-isis-ipv6u)# multi-topology transition