Functions of the computer network system
(1) Resource sharing:
　　Resource sharing is based on resource sharing network, is one of many networks do not seek the interests of fans, some of his own through some of the data collected resources through platform sharing to everyone, but with the development of economic and social resources, networks and shared in the community are also exposed a number of issues.
　　1, data and application sharing:print sharing within the LAN set up a print server, you can provide print services for all LAN users.
　　2, the mail server can provide e-mail functions based on the user name of mail forwarding, distribution, CC and other services, and can be done easily manage on the server, backup, delete, recover, restore and other work for all employees within the enterprise.　
　　3, online chat is the most common Whiteboard, Netmeeting, WebEx and other applications in real time, achieve rapid subscriber located in different physical locations between video communication.
　　4, real-time messages such as: Yahoo IM, MSN and other applications, can achieve LAN forwarding messages within the Internet range.
　　5, the database database server is an important part of corporate LAN, you can share data, reduce redundancy, centralized storage and management, maintainability, and security features.
　　6, network storage is a common file-sharing services, using FTP and TFTP services, enabling users to easily on a workgroup computer, and secure access to resources on a shared server, ftp resources and mostly free.
　　7, with the development of resource backup network attacks and viruses, backup resources has also become an integral part of the sharing of resources among, most modern and efficient resource companies to take real-time backup to the network crashes when to maximize the protection of the company information, as well as play the biggest role when disaster recovery.
　　8, connections: including customer resources, capabilities and resources that can apply to each other.
　　9, equipment.
(2) Data communication:
　　Data communication is a new communication way communication and computer technology to combine and produce. To transfer information between the two must have a transmission channel, depending on the transmission media, wired data communication and wireless data communications points. But they are all over the transmission channel data terminals and computers linked together, leaving the data in different locations to achieve terminal hardware and software and information resources sharing.