This read-write OCTET STRING, when written with a big-endian FDDI address, causes the ES/1 to issue an SMT NIF request to determine that station's upstream neighbor on the FDDI ring identified by fddismtIndex, with a trap sent to the NMS once the response is received. An administrator uses this as an active diagnostic trigger for tracing FDDI ring topology on a specific board. For example, the admin writes a station's address to fddismtUpstreamReq on the board identified by fddismtIndex to trace the physical cabling order around a misbehaving FDDI ring.