| Along with the rapid development of the Internet, there has been an explosive increase in the types and scale of Internet application, then wireless Internet bandwidth resource gradually seems inadequate. Besides, the rapid updating and generation shift of hardware have brought a growing number of terminals equipped with multiple network interfaces. When a single NIC for data transmission can not meet the bandwidth requirements of high-speed network business, we can use the multiple NICs (internal or external) of the terminal for joint data transmission, thus improving the network throughput and network stability.By using multi-nic joint transmission scheme on different protocol layers, and combining the current network architecture, this thesis choses the protocol layer and transport protocols that are best for the implementation of multi-nic joint transmission scheme, namely the transport layer and MPTCP protocol. This thesis studies the core technology of MPTCP protocol and analyzes its problem in multi-nic joint transmission, i.e., packet disorder caused by different performance of transmission sub-flows in MPTCP. It can not only cause the receiver buffer overflow, but also cause unnecessary fake re-transmission, which will further degrade the whole network throughput. Aiming at the problem, in this thesis, the path scheduling mechanism of the standard MPTCP protocol is modified, and a multi-nic transmission scheme based on link quality estimation is put forward. In this scheme, firstly, all transmission sub-flows in the MPTCP protocol are divided into the available flows and the standby flows, and then the one which has the best quality of link is chosen from available sub-flows for the current data transmission. Therefore, this scheme effectively mitigates the problem of packet disorder and improves the network throughput after the aggregation of multiple network bandwidths.In addition, the current Internet applications are growing more different and complex. Fully considering that different applications have different requirements for QoS technical support and the traditional QoS technology cannot satisfy the multi-nic joint transmission, this thesis proposes a multi-nic transmission technology based on application identification. This scheme can effectively identify the network application, and choose nic to do data transmission according to different QoS requirements of different application types, thus increase the utilization of network resources.Moreover, in NS-3 simulation tool, this thesis adds the modified MPTCP protocol module, and makes a simulation analysis of MPTCP protocol which combines the path scheduling algorithm based on link quality. The result verifis that the optimized MPTCP, compared with the original MPTCP, improves the network throughput and network stability.Finally, in this thesis, the Linux test bed is set up to test the function and performance of the application identification module based on machine learning algorithm and multi-nic scheduling module based on application identification. The result shows that application identification module can improve the accuracy of the application identification, and the multi-nic scheduling module can choose the suitable nic to transmit data according to the types of the applications. |
