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

Broadcast and select optical networks offered an attractive way of building LANs and MANS of high bit rates. However, the disadvantages of this architecture such as high cost, power waste, and poor security necessitate finding a solution far 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 proposed medium-access protocol called pre-broadcast select (PBS). The protocol is modeled and analyzed using the equilibrium point analysis (EPA) technique to examine the network's performance, by evaluating the system's 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.