Research On The Assembly Algorithms Based On NS2 In The Optical Burst Switching Networks

Optical Burst Switching (OBS) network belongs to those three optical switching networks which have been studied extensively in current days. The most important feature of OBS is that the control data packet and information data packet are transmitted along separate channels. This transmission mechanism not only reduces the delay which caused by the path-building, but also avoids the necessary for the optical buffer (or the optical RAM) which current optical techniques can not perfectly solve. Hence, the OBS becomes one of the key issues in optical networks.The assembly algorithms in the OBS edge node are chosen as the research objective, and the research method is mainly through software simulation. Firstly, the hierarchy of OBS network as well as the structure and function of core node and edge node (the edge node is emphasized) are summed up. Further more, the assembly mechanisms in current research papers are concluded. And then, the self-similar traffic models are discussed.In the course of studying the assembly algorithms, the basic assembly algorithms are emphasized. And three typical assembly algorithms are simulated in the novel simulation models based on NS2. They are Fixed Burst Length (FBL) algorithm, Fixed Assembly Period (FAP) algorithm and Hybrid Threshold Assembly algorithm which is also named as Max Burst-Size Max Assembly Period algorithm (MSMAP). The simulation results are compared and discussed in this thesis. Besides the work above, an improved adaptive assembly algorithm is proposed. The new algorithm can adjust the length thresholds according to the properties of the input network traffic stream adaptively. The simulation results show that the improved algorithm can effectively reduce packet loss rate.