NETWORKS

NETWORKS

1. Choosing a Network

   • Cost of Network
     • Initial purchasing of equipment. Installation and training. 
   • Size of Organisation
     • Needs range from a small LAN to a global WAN.
   • How the system will be used
     • What type of applications do users require? 
   • Existing systems to integrate
     • More often networks are not started from scratch but need to fit in with existing systems.
   • Performance in terms of reliability
     • Different parts of the organisation may have different performance requirements. 

2. Types of networks

   • Peer to peer
     • A network arrangement where each computer is of equal status.  A group of workstations networked together. 
     • Cost
       • cost saving- no server is needed, so all the computers can be the same. 
     • Status
       • all machines have same status
     • Knowledge
       • no network manager is needed- all uses take responsibility for the network.
     • Set up
       • easy to set up- they are the simplest of computer networks, can be set up by anyone.
     • Reliance
       • no reliance on a server- no worry about the server breaking down. 
     • Responsibility
       • peer responsibility- users decide what resources others can use on their computer.
   • Client Server
     • A network where several computers are connected tone or more servers. 
     • Cost
       • more expensive- servers are expensive to buy
     • Status
       • one machine more important than the rest
     • Knowledge
       • need specialist knowledge. need a person with technical knowledge to manage network
     • Set up
       • network operating systems require technical knowledge to set up and maintain
     • Reliance
       • if server breaks down network is unusable
     • Responsibility
       • users need little specialist knowledge as administration is performed centrally
   • Ring
     • Messages are passed around all devices on the ring and repeated on to the next if not at the destination address. 
     • Advantages
       • Each computer has the same access so no one computer can hog the network.
       • Higher transmission speeds
       • No collisions
     • Disadvantages
       • Faults are difficult to locate
       • Impossible to keep the network running whilst equipment is added/ removed because there is only one path.
       • Break in cable and the network won't work
   • Star
     • The file server is in the centre with peripherals at the end of each connection. 
     • Advantages
       • If one of the cables fails, then the other computers an still be used.
       • Extra computers can be added without much loss in performance because all computers have their own path to the server
       • Easy to add extra computers without disturbing the network
     • Disadvantages
       • Higher cost- large amount go cabling makes it more expensive topology
       • Dependence on the central hub- the the device at the centre of the network fails, then the whole network fails

3. Auditing keeps a record of who logged on, what details of files were accessed and when they logged on and off.

4. Network Manager tasks

   • check outgoing emails
   • guide users though problems
   • control stations
   • log users off left on computers
   • send instant messages

5. Wifi

Images and files in the map