Modeling and Synthesis of Traffic in Optical Burst-Switched Networks

We analyze burst assembly process as the main building block of the optical burst switching (OBS) paradigm. The analysis is performed for time-based, volume-based, as well as hybrid burst assemblers. Under the assumption that the process of packet arrival to the assembly buffer is Poisson, exact analytical expressions are derived for length and interdeparture time of bursts that are generated by these three classes of assembly algorithms. Furthermore, we consider the issue of generating burst trace, which arises during the performance evaluation of OBS networks through discrete-event simulation. In such a simulation study, a significant part of the simulation time, particularly in the case of a network with a large number of ingress nodes, is used by the implementation of the burst assembly algorithms. This is due to the fact that each data burst is a result of aggregating several short-length packets, which-in a straightforward approach-have to be individually generated and, afterward, ldquomeltedrdquo into the burst. We present a novel approach to fast generation of bursts, which is based on the analytical models that are developed for burst length and burst interdeparture time distributions as well as an efficient generation technique (composition) supporting the generation of these distributions. The analysis is completed by numerical results that validate the accuracy of developed models and demonstrate the speedup gain of using proposed burst generation algorithms.