摘要 本毕业论文（设计）是在Visual Basic 6.0编程环境下实现的，主要研究如何使用交换机和利用VB程序设计语言来开发一套图形界面的校园网交换机节点管理程序，对交换机各端口进行设置，修改某一子网在指定时间内的连通状态。完成此管理程序能够方便的管理校园网的交换机节点，减少管理员定时开通或关闭子网的工作量。该程序使用VB自带的Winsock控件telnet到交换机的某一端口，然后通过对交换机发送一系列命令，来设置交换机各Vlan和端口的相关状态；将交换机各子网的相关信息、修改子网连通状态的时间信息等存储在文本文件中，使用一个timer控件定时访问这些文本文件来决定是否修改某子网的连通状态，然后使用访问控制列表（Access Control List, ACL）来修改。通过完成这个题目，加深对交换机的理解，并且更好地学习编程思想，掌握VB语言的应用，了解软件开发的过程，为以后进一步的研究打好基础。
关键词 VB，交换机，Winsock控件
Port Subnet Administrator
Abstract: Accomplished in Visual Basic 6.0 programming environment, this graduation thesis mainly studies how to make use of the switch and employ VB Programming Language to develop an administration program of a series of graphical interfaces campus web switch modes, setting up the switch ports and modifying the state of connection of some subnet in a certain time. The program can conveniently control campus web switch nodes so as to decrease the administrator’s work load that he turns on or off the subnet timely. Using Winsock control in VB, the program telnet the some port in switch. Then, by sending a series of orders to the switch, it puts up the state of connection of switch VLAN and ports. When the information relative to the switch subnets and the time information about modifying the state of connection of subnets are stored in the text files, the program using a timer control to open these files timely in order to decide whether it is revised the state of connection of some subnet or not, and then it is employed ACL to revise it. By finishing this paper, I get deeper understanding about the switch, learn more about the programming thought, grasp the application of VB Programming Language and know the process of developing software. All of these aspects lay the good foundations of my further research in future.
Keywords：VB，Switch，Winsock control
