This read-only Integer32, expressed in bits per second per its description, reports the sum of all ComPort upstream CBR rates currently active on this OC-3 port, counting only acquired ComPorts. It tells an administrator the real upstream constant-bit-rate load currently in use on the optical trunk, distinct from the configured total. For example, an operator sizing OC-3 backbone capacity would monitor this active aggregate over time rather than relying solely on the static configured value.