说明：  经典的NS入门教程，详细分析了ns仿真原理，使读者快速入门，然后讲解了NS仿真步骤以及重要协议的仿真过程，对无线网络学习者是很好的辅助手册。
(NS Tutorial classic, ns simulation of a detailed analysis of the principle, so that readers gain a quick entry, and then explain the NS simulation steps and simulation of important agreements on the wireless network is a very good learner support manual.)