Networks

Networks

1. disadvantages of not having a network

   • If you changed your password on one computer, it would only affect that computer
   • If you saved your work on one computer, it would only be on that computer
   • if your computer wasnt connected to the printer you would have to go to one that is.

2. Types of Network

   • LAN
     • Local Area Network
       • A network that spans a large geographical area, or multiple organisations Often consists of multiple LANs networked together
   • WAN
     • Wide Area Network
       • A network contained in a single geographical location or organisation

3. Disadvantages of having a network

   • Is expensive, extra wire and hardware needed
   • More room for things to go wrong, it could effect every computer
   • Viruses can spread through the network and effect every computer.

4. Advantages of having a network

   • Your files are available on any computer you use not just 1
   • You can print, use the Internet, and email.
   • You can log onto any computer using the same username and password

5. IP Adresses

   • an IP Address is unique address asigned to every computeron a network
   • messages on an IP Address attached, which is how a computer knows whether or not to keep the message
   • there are 4 billion IP Addresses possible

6. 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
     • DISADVANTAGES
       • High chance of catastrophic failure (if any cable breaks or any computer goes down, the entire network fails
       • Difficult to add new computers
     • ADVANTAGES
       • Cheap to install (one cable per computer)
       • No collisions - only one computer is transmitting on each cable

7. STAR TOPOLOGY

   • All computers are connected to a central switch. The switch directs the traffic to the appropriate computer
     • DISADVANTAGES
       • Expensive (needs a lot of cabling, and a central switch, which is expensive)
       • Failure of the switch will take down the network
     • 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)

8. 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