使用SHELL实现泊松分布，指数分布。对于模拟网路流量和拥塞阻塞分析特别有用处。实现用户数据泊松到达，数据包大小指数分布。-SHELL achieved using the Poisson distribution, exponential distribution. For the simulation analysis of network traffic and congestion congestion particularly useful. Poisson arrival achie