Networks

• What is a LAN

  limited to a single location

  Connected using dedicated hardware
• What is WAN


  Geographically larger over multiple sites

  Connected using shared hardware
• 3 factors that affect the performance of a network

  bandwidth - how much traffic can be transmitted on the

  Number of users - the more the bandwidth will have to be shared.

  method of connecting-Wired connections are much quicker than Wi-Fi
• What is meant by Peer-to-peer

  •  does not have a central server. All devices are equally important.
• What is meant by client server

  has a server that controls the other devices
• Network hardware

  Wireless access point - Allows devices to connect wirelessly to a network

  Switch - Sends data between devices on a network.

  Router - Sends data between networks

  Network Interface Card - Allows the computer to connect to a network.

  Transmission Media - The cables used to send data between devices
• What is the difference between the Internet and the World Wide Web?

  Internet is a Wide Area Network – it connects millions of computers across the world

  world wide web (WWW)
• DNS  

  makes it possible to use URLS
• How does DNS work

  When a user types in a website into their browser, the browser sends a request to the DNS to find the IP address of the web server
• What is meant by hosting

  This means the website files are stored and made available on the world wide web
• The Cloud


  ata stored in the cloud is simply stored on a computer
• Web Server

   a computer that makes websites available on the world wide web
• Wired Networks

  connected via cables

  fast to transfer data

  fixed to one location
• Wireless networks

  do not use wires so users are free to move around

  data transfer speed is slower and interference
• Bluetooth

  Bluetooth is a standard for connecting devices together wirelessly
• Encryption

  • Encryption is scrambling a message so that it cannot be understood.
• MAC address


  given to a device when it is manufactured. It never changes
• Standards

  agreements that manufacturers follow so that their devices work together
• Protocols

  TCP/IP -All network traffic. Splits data into packets

  HTTP-Web pages (no encryption)
• FTP

  Transferring files
• POP

  Receiving / downloading emails
• IMAP

  Receiving / downloading emails – a copy of the email is left on the server
• SMTP

  Sending emails
• Layer

  multiple protocols are used together
• The benefits of using layers

  Breaks the problem down into smaller, more manageable chunks

  • Each layer is self-contained
  • One layer can be changed without affecting the other layers