Unit 1.3 Computer networks, connections and protocols

• the main components of a computer are the cpu, memory, storage devices, input/output devices, and communication links
• Topology

  The logical arrangement or physical structure of computers and network devices e.g. Mesh, Star

  
• Transmission Medium

  The physical system used to carry a communication signal from one computer to another e.g. cable or WiFi

  
• Packet


  Small units of data used to transfer files over the internet

  
• Star Network


  A network topology with a switch or hub at the centre and computers connected around it

  
• Mesh Network


  A network topology in which every device within the network is connected to every other device

  
• NIC (Network Interface Controller)


  An internal piece of hardware that allows a device to connect to a LAN

  
• Packet switching


  Packets are sent to their destination along different routes, and reassembled in the right order when they arrive

  
• LAN


  Local Area Network - network that covers a small geographical location

  
• WAN

  Wide Area Network - network which connects networks in different geographical locations

  
• Server

  A device which provides services to other devices (clients)

  
• Client

  A device which requests data from a server

  
• Permissions


  Individually set user access rights on a network

  
• Client-Server


  A type of network managed by a server, which takes requests from client devices

  
• Peer-to-Peer


  A network in which all devices are equal and connect directly to each other

  
• Media access control (MAC)


  A hardwired address assigned to all network devices during manufacture - needed to connect to a LAN. On all NIC's

  
• Sw

  itchConnects devices together on a LAN and directs frames of data to the correct device - intelligent device

  
• Router


  Devices that connect networks together, directs packets over the Internet.

  
• Domain Name Server

  A server which stores website domain names and their IP addresses in a look-up table

  
• I.P. Address


  A unique identification address assigned to network devices to allow it to communicate on the network

  
• Hosting


  The storing of a website on a web server accessed via the internet

  
• Cloud storage


  The remote storing and accessibility of files and applications via the Internet

  
• Wireless Access Point

  A piece of hardware that allows devices to connect wirelessly

  
• Internet


  A WAN which which connects devices and networks from all over the world.

  
• Partial mesh

  A decentralised network similar to a full mesh but not all devices are fully connected.

  
• Frame


  Small units of data used to transfer files over a LAN

  
• Latency


  The delay from transmitting data to receiving it. Latency is caused by bottlenecks in the infrastructure of the network.

  
• Error rate

  Less reliable connections increase the number of errors that occur when data is transferred, resulting in data having to be resent. The signal quality of wireless is dependent on the range of the device.

  
• WiFi Frequency


  The rate at which the signal changes/ number of times it repeats per minute of time
• WiFi Channels


  choice of channels allows users to reduce interference from other devices
• Radio Waves


  The type of 'wave' used in WiFi technology
• BlueTooth

  a radio wave technologyfor short distance communication
• Network standard


  specifies the way that computers access network e.g. speed, physical cable or wireless
• Protocol

  A set of rules governing the exchange or transmission of data between devices on the Internet/network
• TCP/IP


  Transmission Control Protocol / Internet Protocol.

  TCP - defines how messages are broken up into packets and reassembled at destination. Also detects errors and resends packets.

  IP - identifies the location of a device on the internet and routes individual packets from sources to destination via routers.
• HTTP

  Hyper Text Transfer Protocol. Used for accessing and recieving webpages in the form of HTML
• HTTPS

  Hyper Text Transfer Protocol Secure. Encrypts the information so that it cannot be understood if intercepted
• FTP


  File Transfer Protocol. Used when transferring files between a client and a server on a network
• POP


  Post office protocol - creates local copies of emails and deletes the originals from the server.
• IMAP

  Internet Message Access Protocol. Stores email messages on a server and allows users to view and manipulate the messages as if stored locally.