The Network Congestion Control Research Based On SDN

In recent years,with the continuous development of science and technology,the demand for Internet users is increasing gradually.And with the continuous expansion of network nowadays,the network congestion problem is more and more serious.As a result,to ensure the network stability and robustness,the congestion control is the key factor.Scholars at home and abroad have put forward some solution for this problem,but most of the research work is based on the traditional network.However,we can find that,without the information of the underlying network and flow property,TCP must increase or decrease the size of the congestion window to adjust to the changes of the network and traffics.But SDN network can provide a new way of thinking to alleviate the network congestion problem,at the same time,the congestion control technology based on SDN has become a hotspot in the research of the network.SDN network has the characteristics of centralized control,and it can obtain the global topology to do the unified management of the network.Therefore,this paper has used this feature to propose a new network congestion control algorithm.In this algorithm,combined with the thinking of the difference between TCP and UDP,and designed a new congestion nodes judging method and started congestion control mechanism when congestion happened,and ultimately to ease the congestion and ensure high link utilization of dual optimization purposes.In this paper mainly contains the following work:1)Implemented a kind of TCP congestion control algorithm based on advertised window dynamic adjustment,and build a test environment.And then compared with traditional congestion mechanism to verify the effectiveness of this algorithm,and pointed out the advantages and disadvantages of this algorithm.Finally,this paper analyzed the limitations of traditional network in the research of the congestion problem,thus put forward a idea that under the framework of SDN to solve the problem of network congestion control.2)Put forward a kind of network congestion control algorithm based on SDN architecture.The main idea of this algorithm is that based on SDN architecture,at first the controller gets each switch port information to monitor whether there has a congestion link,if network congestion happened,then starts the congestion control mechanism to select one or more appropriate data stream and calculate the shortest path to reroute,finally relief the congestion and guarantee the high link utilization3)Do the experiment and analysis to verify this algorithm.Building a experiment platform,and through the simulation and experiment results to analysis,so as to verify the algorithm optimization effectiveness in congestion control,link utilization and the time complexity.