Research And Design Of Data Center Multipath Transmission Mechanism Based On SDN

With the continuous development of emerging technologies such as big data,network application scenarios are more abundant,which makes the network traffic grow rapidly,and the scale of data center is also expanding quickly.The traditional network architecture and traffic scheduling mechanism cannot meet the rapid development of the network.The emergence of software-defined networking(SDN)provides new ideas for solving the above problems.Because the multi-path transmission mechanism currently used in the data center does not consider the real-time status of the link,and does not make a reasonable distinction between the mice flows and the elephant flows,this paper uses the SDN's features of global view and programmability to optimize the existing multi-path transmission mechanism of the data center so that the transmission performance of the network can be improved.The main work of this paper is as follows:(1)The two-stage flow detection method combined with s Flow and controller is proposed to distinguish the flows between mice flows and elephant flows,which provides the support for the optimization of the multi-path transmission mechanism.The first stage is to use s Flow technology to prejudge the type of the flows.We use the s Flow Agent to sample the flows,and use s Flow Collector to receive the s Flow datagrams which contained the information of sampled flows and analyze the byte of the flows.Comparing with the preset threshold,the s Flow Collector divides the flows into mice flows and suspicious elephant flows,and sends the information of suspicious elephant flows to the relevant module of the controller.The second stage of flow detection is that the controller makes a second judgment on the received suspicious elephant flows,and the decision basis will be dynamically adjusted according to the average remaining available bandwidth,so the controller can filter out the real elephant flows among the suspicious elephant flows.(2)In view of the existing data center multi-path transmission mechanism does not consider the problem of the network real-time load and the distinction between mice flows and elephant flows,the multi-path transmission mechanism is optimized.The controller adopts different path selection strategies for different link load conditions and flow types.When the link bandwidth resources are sufficient,the ECMP algorithm is directly used to forward the flow.When the link utilized bandwidth exceeds the threshold,the controller reads the information of elephant flows and mice flows.For elephant flows,firstly the multi-path transmission mechanism uses the KSP algorithm to calculate K short paths,combines the link bandwidth and delay information to calculate the path cost,and then selects the path with the smallest path cost to forward the flow.For mice flows,the multipath transmission mechanism selects the path with the largest remaining bandwidth to forward the flow.(3)Using the Mininet platform and Ryu controller,we implement the multi-path transmission mechanism of the data center proposed in this paper.The feasibility and effectiveness of the mechanism is verified from the aspects of network throughput,average link bandwidth utilization,average delay and complexity by comparing with the ECMP algorithm and Pure SDN algorithm.The experimental results show that the multipath transmission mechanism proposed in this paper has better performance in network throughput and average link bandwidth utilization.