Computing Topic 3

• What is LAN and WAN?

  Local Area Network (LAN): when computer systems are situated geographically close

  Wide Area Network (WAN): computer systems geographically distant from each other
• What is a client-server network?

  Where clients make requests to a server and the server manages the request and responds

  Advantages: controlled centrally from server to backup data & improved scalability

  Disadvantages: traffic congestion will slow down network & a single fault can cause whole network to fail
• What is a peer-to peer network?


  Where data is shared between systems without requiring a central server

  Advantages: not dependent on server & files can be shared quickly

  Disadvantages: more devices connected can decrease performance & no central device is present to manage security
• What is a star topology?

  Where each computer system is connected to a central device (switch)

  Advantages: Improved security as data packets are sent directly to and from switch, transfer speeds are fast

  Disadvantages: Expensive as extra hardware is required, a single fault causes whole network to become unuseable
• What is a mesh topology?

  Where each computer system is connected to every computer system

  Advantages: Can withstand large amounts of data traffic & new systems can be added without disrupting the entire topology

  Disadvantages: large amounts of cables are expensive to install and maintain, redundant cabling
• What factors affect a networks performance?

  Bandwidth, number of users at same time, number of data collisions and interference
• What are some network devices?

  Wireless Access Point - provides a link between wired and wireless networks. It creates a wireless local area network that allows WiFi-enable devices to connect a wired network

  Switch - connects devices on LAN and receives data packets

  Routers - transfers data packets between networks & also stores the IP address of each computer connected to it

  Network interface card - required to connect to a network
• What are some examples of transmission media?

  Ethernet cables - used typically on LAN to transfer data

  Fibre optic cables - very fast but more expensive, sends data quickly along a WAN

  Coaxial cables - older, slower, copper cables affected by electromagnetic interference
• What do wired connections use?

  Physical cables, such as coaxial or fibre optic, and require a network interface card (NIC) to connect to a network

  It has restricted movement but are more faster and secure
• What do wireless connections use?

  Wifi or Bluetooth uses no cables but requires a wireless network interface card.

  It has freedom of movement, however performance is slower due to devices distance from router and is less secure
• What is a protocol?

  A set of rules that allow devices on a network to communicate with each other
• What are examples of network protocols?

  HTTP, HTTPS, FTP, POP3, IMAP, SMTP and TCP/IP
• What is a layer?


  A group of protocols which have similar functions
• What are the 4 layers?

  Application, Transport, Network and Link