Performance improvement for very high-speed DWDM optical metropolitan-area networks using a passive star topology

Broadcast and select optical networks offer an attractive way of building LAN and MAN of high bit rates. However, the disadvantages of this architecture such as high cost, power waste, and poor security necessitate finding a solution for these problems. In this paper we propose a new architecture which aims at minimizing these drawbacks. The new architecture is based on an optical passive star topology and a new medium-access protocol called pre-broadcast select (PBS). The protocol is analyzed using the equilibrium point analysis (EPA) technique to examine the network performance by evaluating the system throughput, and to investigate how it is affected by the various system parameters such as offered load, timeout duration, message size, and number of stations. We found that, for a given message length, there is a timeout duration, at and after which the throughput is optimized to a great extent with accepted values of delay and lower timeout and blocking probabilities.