Networks.

Networks.

1. Factors to consider when choosing a network

   • Cost of a network
   • Size of organisation
   • How system will be used
   • Existing systems to intergrate
   • Performance and speed required
   • Security issues

2. Types of netoworks

   • Peer to Peer Networks
     • All stations joined together in a network with equal status
       • Advantages
         • Easy to set up
         • No reliance on server
         • Low operating costs
       • Disadvantages
         • Slow proccessing of tasks
         • Only works on small networks
         • Security and Backup not centralised
   • Client Server Network
     • Networks that have computers or terminals that are connected to a powerful network server
       • Advantages
         • Fast proceesing of tasks
           • Can manage large networks
             • Centralised Security
       • Disadvantages
         • More expensive
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3. Network Topologies

   • is the layout of computers together
     • 3 topologies- Bus/Ring/Star
       • Bus
         • Workstations connected to a main central bus
           • Advantages
             • less cable needed than a ring
               • easy to add nodes by removing terminator
                 • If one workstation goes down. Others continue
           • Disadvantages
             • Heavy traffic can cause network failures/delays
       • Ring Network
         • Has no central host
           • Advantages
             • Very high transmission speeds
               • No collisions
                 • Lower cable costs than other topologies
           • Disadvantages
             • Difficult to extend ring
               • Faults difficult to locate
       • Star network
         • Each node connected to a CPU at centre
           • Advantages
             • Easy to add extra computers
               • Computers have their own path to hub
           • Disadvantages
             • Network is vulnerable to central hub failures

4. LANs and WANs

   • Internet- Wide area network-its a huge collection of networks connected together by gateways
     • Intranet-is set up entirely within a LAN. Web pages can be stored and accessed from anywhere on the network and email can be sent internally
       • Extranets-if a company allows some access from out side the intranet.
         • Access would be through a firewall

5. WI-FI

   • Advantages
     • allows inexpensive LANs to be set up without cables
       • allows people to work anywhere where there is a signal
         • Tidier desktop-no trailing cables
   • Disadvantages
     • high power consumption-laptops exhaust their rechargable battries
       • Security problems even if encryption is used
         • Transmission speed slower than cable

6. User Accounts and logs

   • Each user has own account
     • Account has access rights to files
   • Auditing
     • Keeps a record of who has logged on
       • Any illicit use can be tracked/evidenced
   • Remote Management
     • Networks managed from other rooms/buildings/across sites
     • Workstations left unattended can be logged off
       • Softwares rebuilt by adding software

7. Factors to be considered when making configuration choices

   • Application Software choices
   • Operating systems & network management software
   • Hardware
   • Range of user needs
   • Future proofing