Research And Application Of MPTCP Congestion Control Algorithm

At present,the MPTCP(Multipath TCP)protocol is a hot spot of Multipath transmission.The key of achieving the final deployment of MPTCP is the collaboration of scheduling algorithm and congestion control mechanism.MPTCP protocol divides the traditional TCP traffic into many subflows,it transmits different subflows to the end node through many paths respectively.MPTCP protocol is fully compatible with the upper application of TCP protocol,and uses data multiplexing increases the efficiency of each link,making full use of network resources,as an extension of the traditional TCP protocol,it's easier to be deployed and applicated.MPTCP congestion control is a hot issue of MPTCP research at present,the essence of which is to associate the congestion of many subflows and circulate the data from the subflow with big congestion degree to the subflow with small congestion,reducing the load of the subflow with big congestion degree,preventing the occurrence of congestion phenomenon.MPTCP congestion control has a standard algorithm called RFC6356,but in the standard algorithm,it puts forward the related problems which haven't been solved explicitly.So,in order to make the MPTCP applicating better,the study of MPTCP congestion control is very necessary and valuable.In this paper,it researches and analysises the problems of the existing MPTCP congestion control algorithm,puts forward the MPTCP congestion control algorithm of estimated effective path capacity of subflow.First of all,it analysises and summarizes the advantages and disadvantages of existing congestion algorithm,and emphatically compares from three aspects of fairness,flexibility and balance congestion,sums up the problems of congestion algorithm in these aspects.Then,it analysises the way of the MPTCP sender to choose subflow with small congestion degree to send data.It designs the algorithm of estimated path capacity of subflow through defining the congestion thresholds ? and ?,analyzesing several kinds of situation with occupancy.Based on it,it puts forward the MPTCP congestion control algorithm of estimated effective path capacity of sub flow.Finally,it designes and implementes the file sharing system called BTOMP(BitTorrent over MPTCP),the system uses MPTCP instead of TCP to send message in P2P file sharing system,and fusions the modified algorithm of MPTCP congestion control.Due to the frame of the system referencing the BitTorrent system,so it's called BTOMP.Because the main design of the system is to verify the superiority of the proposed algorithm,so in this paper,the BTOMP system realizes the functionality of BTOMP clients and BTOMP Tracker mainly.In this paper,with the simulation experiment and the simple application in the system,verifies the advantages on load balancing of the proposed algorithm which named the MPTCP congestion control algorithm of estimated effective path capacity of subflow.It is feasible and effective.