Studies Of Optical Burst Switching Network Scheduling Algorithm And NS Simulation

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 data scheduling algorithms in the OBS are chosen as the research objective,and the research method is mainly through NS2(Network Stimulation Version 2).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.Detail introduction two types of key technology programs in OBS:resource reservation and unexpected competition.Base on these two types of key technologies,introduce two types of data-based scheduling aloorithmbased on without void or with void(LAUC & LAUC-VF).At the same time,we extended the algorithm of with void,then using geometric and pesudocode to introduce the algorithm of Min-SV and Best Fit.Through detail introduce the hierarchy and the component of NS2,familiar the mechanism of NS2,understanding the shortcomings of NS2:did not provide simulation support for OBS based on WDM,such as optical switching node,multi-wavelength link,the distribution of wavelengths,the new module scheduling data and scheduling mechanism.So we must add a new type of data scheduling module base on OBS for NS2,then achieve the above-mentioned two types of data scheduling algorithm.Through add a data scheduling module in NS2,with other basic modules together to create a general simulation platform,this platform laid a solid foundation for more in-depth study of OBS network performance.Setting up the general OBS simulation platform as the basis,and the scheduling modeling for the media,provide the interface for a new data scheduling algorithm,then through the simulation to assess the performance of the algorithm.Through the simulation to get the data of two types algorithm:packet loss rate and scheduling time.The simulation results show:as a result of new information framework,In the computing time:Min-SV is faster than LAUC-VF,and similar with LAUC;In packet loss rate: Min-SV is lower than LAUC,similar with LAUC-VF.Although the scheduling time of without void is performance better than with void,but sacrifice for the performance of packet loss rate. The different algorithm of with void,the performance of algorithm is closely related to the complexity of the algorithm.Due to the new data architecture and less complexity,so Min-SV has a relatively good performance.At the same time through the simulation platform for the introduction of FDL to resolve unexpected competition,found that FDL can reduce the packet loss rate,then reduce the rate of business obstruction,to improve the performance of system.