The value of the object tmnxIsisReferenceBw specifies the reference bandwidth that needs to be used to calculate the cost. To configure higher reference bandwidth values, please use the newer objects tmnxIsisReferenceBwU64High and tmnxIsisReferenceBwU64Low in tmnxIsisExtTable. In case a reference bandwidth is configured in tmnxIsisExtTable that exceeds the maximum of the tmnxIsisReferenceBw range, this object will return the maximum value. The real reference bandwidth can be found in tmnxIsisReferenceBwU64High and tmnxIsisReferenceBwU64Low. In order to calculate the lowest cost to reach a given destination each configured level on each interface must have a cost. If the reference-bandwidth is defined then the cost is calculated using the following formula: Cost = reference-bandwidth / bandwidth. If the reference bandwidth is configured as Ten Gig (10,000,000,000) a 100-Mbps interface has a default metric of 100. In order for metrics in excess of 63 to be configured wide metrics must be deployed. A value of '0' means that the reference bandwidth is not defined.