DQDB: slot reuse and preuse

The authors propose a simple modification to the existing distributed queue dual bus (DQDB) protocol to improve the channel utilization. The network throughput does not degrade appreciably when the channel speed and physical distance of the network increase on the current DQDB-based network. However, as the bus length of the DQDB is increased, the slot usage becomes a problem. Since the slot is used only once when traveling a long distance, the current DQDB protocol becomes inefficient in channel utilization during the slot allocation. To avoid inefficiency in channel utilization, a revised distributed algorithm is proposed to improve the channel utilization using slot reuse and preuse with minimum modifications of the access control field (ACF) and distributed queuing algorithms on the current DQDB protocol. This proposal suggests one possible channel access solution for the gateway of the interconnected DQDB metropolitan area network (MAN)