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BASICS

Architecture

TOPOLOGY

NETWORK DEFINITION A collection of computers and mobile devices connected together via communication devices and trasnmission media  Usage Sharing an internet connection among several users Sharing an application software,printers and ther resources Exchanging file among network users and over the Internet Communication Devices Hardware component that enables a computer to send and receive data, instructions, and information to and from one or more computers Components Definition Hub/Switch A communication device that enables a computer or device that enables a computer  or device that doesn't have built-in networking capability to access network Modem A device that enables a computer to communicate over analog networking media such as connecting the Internet via telephone lines Wireless Access Point A communication device that enables a computer or device that doesn't have built-in networking capability to access network Router A device that connects multiple networks together, routes packets to their next location in order to efficently reach their destination Network Interface Card An adapter card that connects a computer to a network Transmission Media The materials or substances capable of carrying one or more signal PHYSICAL (send signals through cable, wire or tangible materials) Twisted-pair cable: consisting of pairs of copper wire that are twisted together Coaxial cable: consisting of center wire inside a grounded, cylindrical shield, capable of sending data at high speeds Fiber Optic Cable: consists of dozens or hundreds of thin strands of glass or plastic that use light to transmit signals Wireless (send signals through the air or space) Infrared: Send signals using infrared light waves from one device to another Microwaves: Waves that provide a high-speed signal transmission using electromagnetic radio wave (P1 WiMax) Cellular Radio: a form of broadcast radio that is in wide use for mobile communication Broadcast Radio: Distributes radio signal through the air over long distances Communication satellite: A space station that receives microwaves signals from an earth-based station Bluetooth: A networking standard for every short-range wireless connections ; the devices are automatically connected once they get within the allowable range Advantages Disadvantages Hardware Sharing: Network facilitate the sharing of hardware devices such as printer Undesirable Sharing: Viruses are easily spread over network and the Internet. Data and Information Sharing: enables many people to access and share the same data such as database and group software development. Security Issues: a computer hacker can get unauthorized access by using different tools. Facilitate Communications: people communicate efficiently and easily via e-mail. Network Hardware, Software and Setup Costs: setting up a network requires an investment in hardware, software of network. Internet Access Sharing: small computer networks allow multiple users to share a single Internat connection. Illegal or Undesirable Behaviour: Typical problem include the abuse of company resources, distractions that reduce productivity, software piracy. Expense/Cost: the initial set up costs of a computer network can be high depending on the number of computers to be connected and the number of connecting devices/training/expert support needed.