Computer Networks

• LAN is Local Area Network
• LAN is a network that connects computers that are geographically close together, such as schools or offices
• WAN is a network that connects computers that are geographically far apart, such as in different countries or across the world
• The 8 factors that affect network performance:

  • bandwidth
  • number of users
  • number of data collisions
  • physical interference, such as walls
  • distance from router
  • amount of data packets needed to travel
  • number of applications being used
  • CPU performance
• Client Server Network is a network that responds to requests from clients
• Peer to peer network is a type of network that connects two client computers directly together
• Client Server can easily back up data and update software
• Hardware and software can be shared when using Client Server
• Client Server allows clients to be easily added to server
• Client Server can contain large amount of traffic which can cause network to slow down
• The whole Client Server Network can fail if the server fails
• IT technicians are needed to maintain a Client Server network
• Malware can spread quickly in Client Servers
• Peer to Peer networks are cheaper to set up and maintain because there is no central server
• Peer to Peer network can quickly share files
• Peer to Peer networks need backups done in every individual device
• In Peer to Peer Networks, the more devices connected, the slower the performance
• The hardware needed in a LAN are:

  • wireless access points
  • routers
  • switches
  • NIC (Network Interface Card)
  • transmission media
• Examples of computer networks used worldwide:

  • DNS
  • hosting
  • the cloud
  • web servers
• Star Topology is a topology where each device is connected to one central node
• In star topology, all data goes to the hub first and then to the computer
• Star topology has improved security as data packets are sent directly to switch
• Star topology has minimal network collisions so transfer speeds are fast
• In star topologies, new devices can be attached directly without network having to shut down
• Extra hardware needed to purchase and maintain a star topology
• If the hub/switch fails, the whole star topology will fail
• Mesh topology is a topology where every computer connects to every other computer
• No hub or switch is needed in mesh topology
• Data packets are transferred along the quickest path in mesh topology
• In mesh topology if one cable fails the network will still work it will just take an alternate route
• Mesh topology can withstand large amounts of data traffic
• In mesh topology, new systems can be added easily
• Mesh topology is expensive to install and maintain because of the amount of cables needed
• cables might be connected to devices that it will never communicate with, waste of cables (mesh topology)
• Wireless Access Point is a link between wireless and wired networks
• Wifi and Bluetooth are examples of Wireless Access Points
• Wireless Access Points can can be a seperate device or built into a device
• Routers transfers data packets between networks
• Router recieves data packets and uses its IP address to see the best route for the data
• Switches connects devices together on a LAN