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COMPUTER NETWORKS CLASSIFICATION

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COMPUTER NETWORKS CLASSIFICATION Network could be classified into following three categories:  Local Area Network. (LAN)  Metropolitan Area Network (MAN)  Wide Area Network (WAN)  LOCAL AREA NETWORK Network used to interconnect computers in a single room, rooms within a building or buildings one site are normally called Local Area Networks (LANs). LANs normally transmit data in a digital form with typical transmission speeds of up to several megabytes per second. These speeds can be achieved using parallel transmission where a cable with multiple core is used, or serial transmission, making use of high frequency carriers, using coaxial cables, fibre optical or even a simple pair of wires because distances are short. Modems are not normally required although some mechanism for converting from parallel to serial transmission and back again may be needed. In Fig.1.1, there is an example of local Area Network as may be used on a single site within an organization. The terminals and worksta
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NETWORK ARCHITECTURE AND COMPUTER NETWORKS

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NETWORK ARCHITECTURE In communications, data is transferred either in parallel or serial. Parallel communications is faster but requires more wires. Serial communications is much slower but requires fewer wires. Serial is more practical for communications with remote sites, and the existing telephone system can be used for the communications link to various locations by the use of modems. Most, if not all, computer networks use serial communications for linking computers. The network architecture defines the message and data formats as well as the protocols and other standards to which the hardware and software must conform to in order to meet certain objectives. These objectives are listed below: Connectivity This objective specifies that the hardware and software, which are built in conformance to the standards, must be able to communicate with each other over the network. Flexibility Due to the constant enhancement in technology or due to the change in the user needs, the network m
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Definition of Networking .

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                         Networking N etworking is the sharing of information and services. Networking is possible when individual or groups have information or abilities that they wish to share with others. Computer networking provides the communication tools to allow computers to share information and abilities. They are three types computing networking  Centralized computing  Distributed computing  Collaborative computing CENTRALIZED COMPUTING Large centralized computers called Mainframes, were used to store and organize data. Local nodes connected to central computer through serial ports. Computing done by Mainframe and process output communicated to terminal via serial port. These terminals consisting of monitor, keyboard, they are known as Dumb terminal. DISTRIBUTED (CLIENT/SERVER) COMPUTING Instead of centralizing all computing processing into a single mainframe, distributed computing uses multiple personal computers to achieve the goals. The chief advantage of this is each per
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