Research On Packet Scheduling Mechanism Base On MPTCP Multipath Transmission In Heterogeneous Networks

With the fast development of communication technology,more and more multi-homed devices that with more than one interface included Wi-Fi,3G,Bluetooth,infrared and so on.However,the traditional TCP protocol can only use one route between the end systems to transmit data at the same time.In order to use the bandwidth resources of the terminals that with many interfaces totally,people put forward the MPTCP(Multi-Path TCP).The protocol is the extension of traditional TCP protocol,using multiple paths to transmit data,and compatible with TCP,as well as improving application goodput.Within the heterogeneous network based on MPTCP,the performance is limited by the parameters such as Round-Trip Time,Packet Loss Rate and Bandwidth that on the path between end-to-end systems.Due to the limitation of receive buffer size and the heterogeneity of networks,meanwhile the MPTCP protocol ensures the sequential delivery to the application layer,resulted in the Head-Of-Line Blocking at the receiver,which has become the research focus of MPTCP transmission.This paper aims to analyze and compare the existing data scheduling algorithms,and proposes a data scheduling algorithm based on maximum blocking delay estimation.The main work of this paper is as followed:(1)We propose a congestion delay estimation scheduler,MPTCP-BT,which aims to minimise blocking at the receiver side in heterogeneous networks.It considered all elements as the congestion window,RTT,time of each packet' s sending and receiver buffer size and the estimated path blocking time delay;Then,according to the change method of congestion window during the congestion avoidance period,calculate the data volume of the path transmission in the blocking delay.The data transmission will choose the path that will not be blocked at the receiver.(2)The NS-3 simulation platform was used to change the kernel scheduling algorithm of MPTCP to realize the Round-Robin scheduling,DAPS scheduling,OTIAS scheduling and we proposed scheduling algorithm.The performance characteristics of the algorithm were analyzed and compared.Experimental performance indicators include completion time of data segment and OFO queue in receiver buffer.The network transmission completion time selected four parameters:long and short subflow,receiver buffer,bandwidth and RTT.The experimental results showed that the MPTCP-BT algorithm can effectively alleviate the block at the receiver and improve the network throughput.