基于网络虚拟实验平台—VLP2P通信库设计与实现.doc

基于网络的虚拟实验平台 —VLP2P通信库的设计与实现 摘 要 随着信息技术的发展，网络无疑为我们带了更多的便利，因此一个好的系统要具有网络功能。针对虚拟实验台系统的实际功能，采用P2P技术作为其网络通讯基础具有很大的优势：降低服务器资源占用，提高通讯传输效率。但由于NAT的广泛使用，使得不同的内网间系统通讯比较困难。希望P2P通讯具有实用价值,穿透NAT实现不同内网间的系统通讯是一个需要解决的重要问题。 在基于网络的虚拟实验平台中，有很多功能涉及到网络通讯，为了提高系统的模块化程度，减少系统重复开发量，将网络通信部分独立出来，设计实现名为VLP2P的P2P通讯库。Network-based Virtual Experimental Platform—— Design and Implementation of VLP2P Communication Library Abstract With the development of information technology, networks will provide us with more convenience undoubtedly. Therefore, a good system must have network functions. According to real functions of the virtual experiment platform, P2P technology has powerful benefits to decrease probability of using server resources and upgrade the transmission efficiency, as a base of networking communication. While, because of the existence of NAT issues, it is difficult to communicate among different local networks. To make P2P communication get values in real application, an important problem required to solve is the system communication among different networks by penetrating NAT. There are many functions related to network communication in the virtual experiment platform based on network. For improve modularization of the system and decrease repetitive developing work, the network communication is extracted as an independent part to design and implement P2P communication library named VLP2P. In the thesis, the testing program for communication library is also designed. With real testament, it has proven that the communication library has achieved the initial purpose.. Key words: Virtual Experiment Platform; P2P Technology; UDP; Penetrating NAT; Socket programming目录 论文总页数：20页 1 引言 1 1.1. 项目背景 1 1.2. 项目介绍 1 1.2.1 虚拟实验平台 1 1.2.2 平台网络通信 1 1.3. 项目要求 1 1.3.1 功能要求 1 1.3.2 B/S与 C/S 2 1.3.3 通信协议的选择 2 1.4. 项目难点及解决方法 2 1.4.1 IP处理问题 2 1.4.2 Client之间的通信问题 2 2. 网络基础知识介绍 2 2.1. SOCKET编程 2 2.2. P2P网络简介(introduction) 3 3. 项目网络通信的实现过程 4 3.1. NAT的一些基本概念 4 3.2. 通信过程 4 3.3. 通信过程总结 7 4. 实现代码及其效果简介 8 4.1. 程序主要功