Design And Implementation Of A Network Performance Emulation System

Since entering the21st century, with the increasingly rapid pace of development of Internet technology and the growing number of new types of network applications, the research on the behavior and performance of network has become a difficult and important task. Network simulation as a tool to study the network behavior played a major role, which is a reproduction of the complex network environment and this method can be explained with two class:One is the Simulation method, the software methods to build a complete virtual network environment, which have the advantages of low cost, fast and convenient, and the drawback is unable to reproduce the real network, and higher distortion, the common simulation software is more complex in operation; the other is an Emulation method running in the experimental network real data stream, and provided to the researcher can be controlled, the network state can be repeated to control the interface, the method combines the advantages of the measured and the simulation method, flexible and efficient and the simulation results.The main topic for emulation of network performance parameters such as delay and packet loss rate, with the construction of delay model and packet loss model, the authenticity of the emulation system further improved. The delay model implemented with the Linux system Netem components, could load the trace file generated by the model, the dynamic delay model emulation using a packet scheduling mechanism. With the Netfilter framework that comes with the realization of the loss function and the packet loss model based on the function, and to modify the system kernel source then recompile. In the part of system functional verification, testing the performance of the delay model and packet loss model of system, a large number of experimental results of performance tests fully demonstrate that the network performance emulation system is designed and implemented to achieve the expected goals, to meet the accuracy and validity which delay emulation error is less than2.5%, the packet loss rate emulated error of less than2%. Finally, utilized an application example, the simulation system used in the performance test OTT (Over the Top TV) transmission mode of the video-on-demand platform, further demonstrates the effectiveness and practicality of the system.