DTQDB: A Fair and Fully Utilized Media Access Protocol for Dual Bus Networks

The distributed queue dual bus (DQDB) protocol with bandwidth balancing (the IEEE 802.6 standard for metropolitan area networks) achieves fairness by sacrificing a fraction of the bandwidth. Many existing protocols indicate that fairness and full utilization might be incompatible in highspeed-high-latency MANs or LANs. The main purpose of this research is to design a protocol called distributed total queue dual bus (DTQDB) that combines the two features together. In addition, the protocol provides bounded access delay that is linear in the round trip propagation delay. The basic concept is to compute, for each station, the latest estimate on the number of active downstream stations, according to the information available, and serve them in a round robin scheme.