Computer networks, connections and protocols

• Computer network


  When two or more computers are connected so they can communicate with each other
• LANs (Local Area Networks) connect devices within a small geographical area such as a single building
• The internet is the largest WAN in the world
• Bandwidth

  The amount of data that can be sent and received successfully in a given time.
• Error rate


  If there are problems on the network data may be sent containing errors or even with some sections of data missing. This means that data must be sent again until it arrives correctly which slows down the performance of the network.
• Latency

  Latency is when there are bottlenecks in parts of the network which delays the messages from getting to their destination.
• Poor network performance

  Low bandwidth, too many devices using the network at the same time and the wrong type of media are the most common reasons that networks may have poor performance
• Client server network

  A centrally managed network controlled by a server
• Peer-to-peer network

  All computers have equal status and share responsibility for installing and updating software and backing up their own data
• Stand-alone computer

  A computer that can work independently or as part of a network
• NIC allocates a unique address on the network and allows a cable to be plugged in to connect to a LAN
• Ethernet cables use a copper core to transmit data through electronic signals
• Switches allow cables to be connected and they direct messages around the network.
• Routers join networks together
• WAPs boost the messages sent through wireless networks
• Domain Name Servers (DNS) allow internet browsers to look up website addresses and find the IP address to locate the website server
• Website host companies allow people with very little website development skills to create their own websites.
• Cloud storage is where data is stored on remote servers accessed by the internet
• Network "topology"

  The shape of the connections on a physical network
• Star topology

  All the devices connect to a central hub or switch
• Mesh topology

  The devices connect to as many other devices on the network as possible
• Bandwidth


  The bits per second that can be sent through a network connection