If your IS-IS single topology supports both IPv6 and IPv4, you can configure both IPv6 and IPv4 on an IS-IS interface for Level 1, Level 2, or both Level 1 and Level 2. However, if you configure both IPv6 and IPv4 on an IS-IS interface, they must be configured to run on the same level. For example, you can configure IPv6 to run on Level 1 on an interface and IPv4 to also run on Level 1 on the same interface. However, you cannot configure IPv6 to run on Level 1 on an interface and IPv4 to run to Level 2 on the same interface.
To configure an IPv6 IS-IS single topology, you must perform the tasks listed below.