单服务台模型，一分析fifo排队规则的分析模型，此代码可以计算出分析数据，而且可以绘出二维分析图-Single-desk model, an analysis of the FIFO queuing discipline analysis model, this code can calculate the analysis of data, and you can draw two-dimensional analysis chart

OPNET软件仿真包交换网络，并在其中加入排队模型并拓展网络拓扑，对于统计量有不同影响(OPNET software simulates packet switching network, adds queuing model and expands network topology, which has different influence on statistics)