External Clock Speed. If external clocking is configured, this
attribute should be set to the clock speed of the externally
supplied clock. Depending on the protocols configured in the
interface, this value may control internal decision making in the
router. In soe cases, router software uses this attribute for route
selection. If Priority Queueing is configured, it chooses queue depths
based on this attribute. This attribute has no effect when Internal
Clocking is configured.