unit 1.5 network topologies, protocols and layers

unit 1.5 network topologies, protocols and layers

1. Networks

   • Advantages
     • Sharing devices such as printers saves money.
     • Files can easily be shared between users.
     • Security is good - users cannot see other users' files unlike on stand-alone machines.
     • Data is easy to backup as all the data is stored on the file server.
   • Disadvantages
     • Viruses can spread to other computers throughout a computer network.
     • There is a danger of hacking, particularly with wide area networks. Security procedures are needed to prevent such abuse, eg a firewall.
     • Purchasing the network cabling and file servers can be expensive.

2. The bus network

   • In a bus network all the workstations, servers and printers are joined to one cable (the bus). At each end of the cable a terminator is fitted to stop signals reflecting back down the bus.
   • Advantages
     • it is easy to install
     • it is cheap to install, as it doesn't require much cable
   • Disadvantages
     • if the main cable fails or gets damaged the whole network will fail
     • as more workstations are connected the performance of the network will become slower because of data collisions
     • every workstation on the network "sees" all of the data on the network – this is a security risk