Networks

Networks

1. Computer networks is a telecommunication network which allows nodes to share resources

   • It is the exchange of data between computers and the personal using them

2. Hardware

   • Ethernet Cable
     • An Ethernet cable is made up of a set of four 'twisted pair' copper wires enclosed in a plastic sleeve with a standard network plug on the end
     • Data is carried through the cables by means of electrical signals
   • Fibre Optic
     • These provide very high bandwidth.
     • Fibre optic cables are made up of many glass fibres held together inside a sheath
       • They use light signals to transport the data, often over a long distance
     • More expensive compared to standard Ethernet (copper) cables
   • Network Controller card
     • Converts the data produced by a computer into a format that can travel along a network connection
     • Convert the binary number to the correct, corresponding signal (electricity for ethernet cables, infra-red light for fibre-optic cables, radio waves for WiFi)
     • The computer on the other end of the network has its own NCC that will convert the signals that it receives back into binary
   • Server
     • Networked computer that is providing a specific service to other computers on the network
     • File server. Users store files on the network file server. Users can do all the usual file functions - copy, delete, change, duplicate by sending commands to the file server
   • Router
     • Manage the data packets enabling them to be sent between networks (e.g. over the internet)
     • They route data packets based on their address information
   • Hub
     • Device that connects nodes together
     • Data packets are transmitted across the whole of the network.
     • Makes all connected nodes act as a single segment
   • Switch
     • Device that connects nodes together
     • Intelligent device that can create and connect to different segments of the network
     • Reduces network traffic because data packets are sent to the nodes or segment where they are needed rather than being broadcast to the whole network

3. Topologies

   • PAN
     • A computer network that enables communication between computer devices near a person
   • WAN
     • Computers connected over a large geographical area
   • LAN
     • Computers connected over a large geographical area
   • VPN
     • Virtual private network
     • Secure, remote access to a private network, usually through a public network i.e. the internet
     • Heavy encryption is used to keep data secure
     • It allows people to work remotely, more secure as all network traffic is encrypted
     • Speed issues due to extra security, increased network complexity

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