Optical Packet Ring Optimization for the Assessment of Tradeoff between QoS and Design Cost

Many methods for finding the optimal design of an optical packet switching ring network are without the performance guarantees, leading to the unexpected network behavior in terms of the QoS performance that network offers to its clients. The inter-dependability between the network QoS performances and the cost optimal design of an optical packet switching ring with a single tunable transmitter and multiple fixed receivers per node, are studied in this paper. First, a method for the cost optimal and stable dimensioning of the ring, focusing on wavelength and receiver costs, is introduced. The method is called the “packet aware design”, as it incorporates the packet properties of the network traffic, in order to offer the insertion queue stability, as an added value. Then, by performing the computer simulations on a set of optimal network configurations, the tradeoff between the QoS performances and the design cost is identified and quantified. The results show how the packet latency depends on the increase of the wavelength utilization factor and the traffic amplitudes. It is demonstrated that the lower node loads result in a better performance, at the same level of the wavelength utilization. Finally, the maximum wavelength utilization factor, for which a ring loaded with the uniform and symmetric traffic achieves the satisfactory latency performance, is found. key words-metropolitan rings; optical packet switching; optimal dimensioning; packet latency; optical transparency; WDM;