Research On Data Scheduling Strategy About Multipath Transmission Based On MPTCP In Heterogeneous Networks

With the development of modern communication technology, more and more intelligent terminal devices have a plurality of communication interfaces. However, the terminal can select only one access link at the same time, other than simultaneously transmit in parallel on multiple links, resulting in a waste of network resources.How to use these paths for parallel multi-path transmission? it has become a hot research in recent years.The traditional TCP protocol, which was produced in the 1970s, is suitable for single stream data transmission, its design and deployment have certain limitations, unable to adapt to the new situation under the transmission requirements.Currently, researchers are working to develop the next generation of communication protocols, so that the host can transmit data through multiple links to increase throughput and redundancy of the network.So far, Parallel TCP,mTCP, SCTP and MPTCP have been produced, all of them have advantages and disadvantages. Due to the good compatible with traditional TCP protocols and applications, MPTCP is an important direction of development.This article is about scheduling strategy based on MPTCP.MPTCP can really improve the throughput and redundancy of the network through the data transmission on multiple paths.However,there are also many deficiencies about MPTCP.First,the research and test about MPTCP are concentrated basically in laboratory conditions,which is different from the real network. Real network is a complex network of heterogeneous factors,bandwidth,delay and packet loss are different.However MPTCP did not take those into account, the scheduling of equal treatment of all links,causing packets received out of order, head blocking, application latency and other issues.Not only can do harm to improving the performance of network,but also cause the overall performance not as good as a single TCP link. To solve this problem,researchers do a lot on congestion control and data scheduling. So far, there isn’t mature and stable solution which is recognized by official. In this paper, we propose a data scheduling strategy, DCB algorithm based on delay and congestion on the basis of previous work.Compared with the Round-Robin algorithm, the algorithm has two improvements:firstly, smooths the RTT value in each sub stream with a change factor. Secondly, in each sub stream, a parameter is introduced to evaluate the congestion condition of the sub flow. At last, data scheduling is determined by this two factors.This paper describes the architecture of multipath transmission solution on each layer first.Then,we introduce the multipath transmission protocols on transport layer,and highlight the SCTP and MPTCP. Then the performance of MPTCP in heterogeneous networks is analyzed.We propose question and describe the existing solutions. After these,we propose a dynamic packet scheduling strategy which can estimate the delay of sub-path reasonably and allocate data in accordance with sub-path delay and congestion status. Compared with the default Round-Robin algorithm, the simulation results show that, this scheduling strategy can improve the throughput of the network and decrease the number of the packets out of order,also can solve the problem about head blocking.