What is a Network? A network is an intricately connected system of objects or people. Networks are all around us, even inside us. Your own nervous system and cardiovascular system are networks. A network is simply a group of two or more computers linked together. An endpoint of a network connection is referred as a node . That is, any device attached to a network, including computer terminals or workstations, peripherals such as printers, and file servers , is a node on a computer network.
Communications Components <ul><li>A sending device , which is generally a computer </li></ul><ul><li>A communication device, such as a modem , that converts the computer signal into signals supported by the communication channel </li></ul><ul><li>A communications channel or path, such as telephone lines, cable, or a wireless transmission link , over which the signals are sent. </li></ul><ul><li>A receiving device that accepts the incoming signal, which is generally a computer </li></ul><ul><li>Communications software </li></ul>Sending Device Modem Receiving Device Communication Channel 1 0 1 0 1 0
Network Benefits <ul><li>Information sharing: authorized users can use other computers on the network to access and share information and data. This could include special group projects, databases, and so forth. </li></ul><ul><li>Hardware sharing: No longer it is necessary to purchase a printer or scanner or other frequently used peripherals for each computer. Instead, one device connected to a network can serve the needs of many users. </li></ul>
Network Benefits <ul><li>Software sharing: Instead of purchasing and installing a software program on every single computer, it can be installed on just the server. All of the users can then access the program from one central location. This also saves companies money because they purchase a site license for the number of users. This is much less expensive than purchasing individual software packages. </li></ul><ul><li>Collaborative environment: enables users to work together on group projects by combining the power and capabilities of diverse equipment. </li></ul>
Communications Media <ul><li>To transfer data from one computer to another requires some type of link through which the data can be transmitted. This link is known as the communications channel . </li></ul><ul><li>To send the data through the channel requires some type of transmission media , which may be either physical or wireless . </li></ul>
Types of Networks Local Area Network A local area network (LAN) is generally confined to limited geographical area.
Types of Networks Wide Area Network A wide area network (WAN) is made up of several connected local area networks.
Network Operating Systems Software <ul><li>Run on the server and provide features such as administration; security; file, print, communications, and database management; and other services to personal computer clients. </li></ul>