NETWORKS

NETWORKS

1. advantages

   • share files
     • the same files are available whichever computers you use
   • share rescources
     • such as printers and internet connection
   • share logins
     • the same username and password can be used on every computer on the network

2. disadvantages

   • Expensive
     • extra hardware and wiring needed
   • More room for error
     • if something goes wrong it can affect every computer
   • Difficult
     • it requires a technical expertise
   • Malware
     • viruses and other malicious software can spread through the network

3. LAN

   • Local Area Network
   • A network contained in a single geographical location or organisation

4. WAN

   • Wide Area Network
   • A network that spans a large geographical area, or multiple organisations
   • Often consists of multiple LANs networked together

5. Network topology

   • is the arrangement of computers and other elements of a network

6. Bus topology

   • The network consists of a single cable that runs through the network
   •  All devices attach to this single cable
   • advantages
     • Cheap to install (only one wire needed)
   • disadvantages
     • High chance of catastrophic failure (a break in the central cable takes out the entire network)
     • High chance of collisions (multiple communications on the same cable that corrupt each other, slowing down the network)
     • More computers mean more collisions, so the network gets slower as it gets bigger

7. Ring Topology

   •  Computers are connected to each other in a ring
   •  Communication only goes in one direction
   •  Each computer receives a message, and if it is not the intended recipient, passes it on to the next computer
   •  No central cable, each connection is between two computers
   • Advantages
     •  Cheap to install (one cable per computer)
     •  No collisions - only one computer is transmitting on each cable
   • Disadvantages
     •  High chance of catastrophic failure (if any cable breaks or any computer goes down, the entire network fails
     •  Difficult to add new computers

8. star topology

   •  All computers are connected to a central switch.
   •  The switch directs the traffic to the appropriate computer
   • Advantages
     •  Fast (low chance of collisions)
     •  Easy to add new computers
     •  Low chance of catastrophic failure (a broken cable only takes out one computer, the rest of the network is fine)
   • Disadvantages
     •  Expensive (needs a lot of cabling, and a central switch, which is expensive)
     •  Failure of the switch will take down the network

9. IP address

   • An address is a unique identifier given to something
   • A house address (such as 15 High Street, Townsville) is an example of an address – each address is unique and used to identify that house
   • IP Address (Internet Protocol Address)
   • IP Addresses therefore range from 0.0.0.0 to 255.255.255.255
   • When the format of IP Addresses were decided in 1983, 4 billion addresses seemed more than enough