Networks

• Types of network

  LAN

  WAN
• LAN

  Local Area Network
• WAN

  Wide Area Network
• Factors affecting network performance

  Bandwidth

  Number of device connected

  Wired connections

  Range of device

  Amount of interference

  Physical obstructions

  Choice of hardware
• Bandwidth


  amount of data that can be transferred in given time
• Number of devices connected


  many devices can cause congestion and slow the network
• Wired Connections

  faster and more reliable than wireless

  fibre optic cables better performance than copper cables
• Range of device


  only certain areas where the network will work well
• Amount of interference


  other wireless networks can decrease the signal quality
• Physical obstructions

  prevent and slow the signal quality
• Choice of Hardware

  other than cables and network topology
• Types of servers

  file server

  print server

  email server

  web server

  database server
• Print server

  organise printing on different servers
• Email Server

  receive emails, detect and block spam, distribute emails to users
• Web server

  host external website of company / school
• Database server

  hold records (of students if in school)
• Advantage of file server

  only one file needs to be backed up and files can be accessed from any computer
• Advantage of Email servers

  provide a central place for email that is then accessed from differnt devices
• Advantage of print server

  manage all files to be printed

  allows one printer to be shared by many computers
• Peer to peer network features

  suitable for small companies with fewer computers

  no central server controls files or security

  all computers can easily see files on all other computers

  all computers can communicate with each other without going through a server
• Advantages of a Peer to peer network

  easier to set up - computers cabled together

  no need for dedicated server equipment

  individual computers can share a printer, router, modem and other hardware

  users can communicate directly with each other and share each other's files
• Disadvantages of Peer to Peer Network

  viruses and malware easily transferred becuase there is no central firewall

  data recovery and backup not done centrally, each computer system has to have its own backup system

  files not centrally organised, hard to locate

  if turned off data cannot be retrieved from other machines