comp important

• LAN stands for Local Area Network
• A LAN is a network which is confined to a single building or site 
• LANs are confined within one location such as a building and are connected using their own hardware infrastructure
• The LAN can be setup to only allow specified MAC addresses to connect, for security reasons
• Advantages of cloud computing

  • You can access your data and applications from anywhere at any time
  • You don’t need a powerful computer with a huge hard drive – everything is stored and run on a remote computer - saves money
  • Responsibility for backing up data and security is transferred to the service provider
• Disadvantages of cloud computing

  • Loss of control - personal data will be stored on another company’s servers
  • Relies on stable internet connection
• Every device connected to the Internet has an IP (Internet Protocol) address
• Routers are any node that can route packets from one place to another
• The Domain Name System is made up servers which store domain names and their associated IP addresses
• POP3 and IMAP4 are used to receive emails from a mail server
• POP (Post-Office Protocol) will download every new message to the device used and at the same time remove them from the email server
• IMAP (Internet Message Access Protocol) will leave the messages on the email server so that they can be accessed by multiple devices
• IP (Internet Protocol)


  • Routes the individual packets from one IP address to another
• Receiving data

  • The link layer takes the MAC address and passes packets up to the Internet layer
  • The Internet layer takes the IP addresses and passes packets up to the Transport layer
  • The Transport layer reassembles the packets into order and passes the data to the Application layer
  • The Application layer uses the correct software to correctly display the data, web page or email for the user
• Advantages of layers

  • Layers are self-contained - The functionality of one layer can be changed without affecting the functionality of other layers
  • Different hardware or software standards operate on a particular layer providing interoperability between providers and systems (This means that manufacturer’s routers operating on the Internet layer, will operate with another manufacturer’s Network Interface Cards (NICs) operating on the Link layer)
• this is a star network

  
• How does wireless access slow down a network?

  Each wireless access point (WAP) only has so much bandwidth to share among connected nodes. The greater the number of nodes that are connected, the less bandwidth each receives and the slower communication becomes.
• the system that matches urls is a domain name server (DNS)