A WASTE-FREE CONGESTION CONTROL SCHEME FOR DUAL BUS HIGH-SPEED NETWORKS

In a high-speed backbone network, each of the nodes in the backbone ma y act as a router/gateway which connects several low-speed LANs, Typic ally, a router/gateway occurs congestion when the traffic from the bac kbone network can not be serviced by the connected LANs. Recently, sin ce the existence of high-speed LANs becomes possible, a router/gateway may also occur congestion when the traffic from the connected LANs ca n not be serviced by the backbone network. In this paper, a waste-free congestion control MAC protocol for dual bus high-speed networks is p roposed to release such congestion. In this protocol, a heavy loaded n ode obtains a faster transmission rate to send the packets so that the congestion can be prevented efficiently. Meanwhile, each of the uncon gested nodes slows down its transmission rate and stores the new incom ing messages into its buffer. We show that the proposed protocol is wa ste-free and hence the throughput of the network is maximized. A simpl e and efficient priority mechanism is also introduced for the proposed protocol to support multi-priority traffic in networks. The efficienc y of the proposed protocol is compared to the well-known protocols for the dual bus networks, such as the DQDB with BBM and the BA-FDQ. Simu lation results show that the proposed protocol is more efficient than the other well-known schemes in terms of message queueing delay, messa ge loss rate, and network throughput.