Interface types to which the reference bandwidth does not apply

Some interface types are not affected by the reference bandwidth and always have the same cost regardless of the reference bandwidth in use:

• The cost of a loopback interface is always 1.
• The cost of a virtual link is calculated using the Shortest Path First (SPF) algorithm and is not affected by the auto-cost feature.
• The bandwidth for tunnel interfaces is 9 Kbps and is also subject to the auto-cost reference bandwidth setting.