The unreserved bandwidth on this interface, at the first priority level or TE-class, in IEEE floating point format, used by CSPF to calculate constrained routes. Each value will be less than or equal to ospfPmIfMaxResBwidth. The units are bytes per second. This is advertised through the routing domain in Opaque LSAs. However, a change to this parameter only causes an origination of a new Opaque LSA when the percentage difference between this parameter and ospfPmIfLastUnresBwidth0 is bigger than ospfPmIfUnresBwidthPcntge. Note that in a DiffServ-TE environment the unreserved bandwidths are indexed on priority level, whereas in a DiffServ-TE environment they are indexed on TE-class.