IS-IS can support several types of metrics, but only the “Default” metric is required to be implemented. It is normally associated with the circuit bandwidth. If other metrics are supported (Delay, Expense, Error) then a new SPF tree is created for each of them. Cisco routers usually support only the Default metric, but each circuit (interface) has a metric of 10, regardless of the bandwidth of that link. It’s up to the admin to change the metrics on the interface with the command: