Study On Concurrent Control Of Sub-Flow By MPTCP Over Asymmetric Multi-path

With the development of wireless communication techniques, the reduction of the cost of electronics devices, as well as the increase of the diversity of network access methods, terminals are assembled by multiple interfaces, which can connect multi-homed networks. Therefore, the multi-home networking technology becomes a vital characteristic of the mobile Internet. However, such a technology is bringing about some new challenges, especially in how to use multiple paths to achieve concurrent transmission, and how to control the allocating of data traffic and the management of receiver buffer. These are crucial for the design of the multipath protocol and the analysis of the transmission mechanism.MPTCP is a widely concerned concurrent transmission protocol. It can aggregate multiple paths to improve data transmission rate. However, due to the defect of the scheduling algorithms in MPTCP, the receiving data will be out-of-order when the data are transmitted on asymmetric paths. These out-of-order data cannot be consumed by the application layer immediately, and occupy much buffer size, leading to the degradation of the throughput. Therefore, a study on concurrent control of sub-flow by MPTCP over asymmetric multi-path is necessary.At first, a self-adaptive concurrent scheduling algorithm based on the transmission delay is proposed. In this algorithm, the Round Trip Time(RTT) is considered when allocating the traffic on each path in the sender. Additionally, the simulation is carried out using NS2 tool sets by loading the MPTCP modules. The experimental results show that the novel proposed algorithm can enhance the transmission efficiency, i.e., the throughput of the proposed algorithm is 61% higher than the round-robin one.Furthermore, this thesis proposes a buffer management algorithm, which processes the data block using the merging method. By simulating the proposed algorithm on the NS2 tool set, its efficiency is verified. The results reveal that, the resource efficiency improves 3.7 times.In general, the main contributions as follows:(1) The experiment results show the relationship between the path difference and the out-of-order arrival data, and the condition of limited buffer size on the throughput performance degradation.(2) A self-adaptive concurrent scheduling algorithm based on the RTT is proposed. The experimental results by NS2 verify the validity of the algorithm.(3) A data block arranging and merging methods in the receiving buffers is proposed. Additionally, the buffer management module is added to verify the storage efficiency of receiving buffer.