This thesis is generally about network performance analysis. It contains two parts.The theory part summarizes what network performance is and inducts the methods of doing network performance analysis. To answer what network performance is, a study into what network services are is done. And based on the background research, there are two important network performance metrics: Network delay and Throughput should be included in network performance analysis.Among the methods of network analysis, there are two types: real target net- work analysis and network simulation. In the practical part, the two types of network analysis are both applied under a same target network layout for the sake of comparing them and find out difference. It turns out that the simulated network by ns-3 tends to give a more optimistic analysis results over the two network performance metrics.