Design And Implementation Of Linux Network Testbed And Context-Aware Congestion Control Protocol

In light of the limitations of traditional experimental method, performance evaluation on real network testbed is becoming a primary experimental approach. This thesis deals with the whole procedure of the design and realization of network testbed, and several key technical issues encountered with the network testbed configuration are explored in detail. Subsequently, we develop a network testbed for the performance evaluation of existing transport protocols, including topology configuration, re-compilation and re-build of Linux kernel, experiment scenarios setup by Netem and Dummynet, TCP socket buffer configuration, ECN enable, traffic generation, and data capture and processing.With the rapid advances of network communication techniques and explosive growth of network applications, the nowadays network is presenting two obvious characteristics: backbone high-speed and edge wireless. Within this situation, the traditional TCP protocol has suffered performance degradation in terms of link utilization and throughput oscillation. Recently, many TCP variants have been proposed for either high-speed networks or wireless networks. However, these TCP variants can not survive in heterogeneous network context because of their inadaptability for various network scenarios. Therefore, it is an urgent issue to enhance the scalability of the transport protocol, and weaken or eliminate the sensitivity to network context as much as possible for high transmission efficiency in heterogeneous networks. A context-aware transport protocol, named JTCP, has been proposed in the dissertation, which is a joint version of CUBIC and Westwood in that CUBIC is capable of utilizing available bandwidth effectively and Westwood is not suffered in wireless network. The proposed JTCP is implemented in Linux kernel, and its performances are investigated in our testbed. Experiment results demonstrate that JTCP obtains satisfactory RTT fairness and maintains fine TCP-friendliness in heterogeneous networks. JTCP can efficiently utilize link capacity in both wired and wireless networks, which detaches the strong correlation between network context and window adjustment mechanism.Finally, the dissertation summaries up our research work in the last chapter. The further research direction on network testbed and protocol optimization has been explored in detail afterward.