A novel approach in modeling multi-service Optical Packet Switched networks with the Preemptive Drop Policy

This paper investigates packet loss in multi-service Optical Packet Switched (OPS) networks, in which the Preemptive Drop Policy (PDP) is adopted to implement QoS differentiation. A novel approximation model is proposed. In contrast with existing multi-dimensional Markov model, which focuses on analyzing the small system with only two service classes and results in non-closed form expressions of the packet loss ratios (PLRs), our model has four major advantages: 1) it is applicable to analyzing a general multi-service scenario, independent of the number of service classes and wavelengths; 2) the closed form expressions of the PLRs can be derived directly; 3) the computational complexity is reduced dramatically; 4) this model shows excellent extensibility for analyzing larger system which supports more service classes or wavelength channels per fiber. The analytical values are compared with simulation results for a three-service OPS network. Results show that the proposed model provides a high degree of accuracy in the PLRs under different network scenarios.