Networks Mind Map

Networks Mind Map

1. Advantages

   • Consistent User Experience - You can log on to any computer in the school using the same username and password
   • Your files are available on every computer you use, even if you created them on a different computer
   • You can print, use the Internet, email and use the same software on any computer

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. Types of networks

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

4. Topologies

   • 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
   • 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
   • 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
   • Network Addressing
     • IP Address
       • Computers on a network also need an address to identify them
       • When a computer is added to a network it is assigned an IP Address (Internet Protocol Address)
       • The IP Address is unique value assigned to each computer on a network
     • Network Navigation
       • All messages that are sent over the network have both the sender and receiver’s IP addresses attached to them
       • Each computer that receives the message checks the IP address
     • The Internet
       • The Internet is a world-wide network
       • Devices on the Internet need IP Addresses, just like any other network
     • Internal networks
       • Globally, there are now more devices on the Internet than the 4’228’250’625 devices it’s possible to assign a unique address to
       • We get round this by assigning an “external” IP address to each house or business, then “internal” IP addresses to the computers in that house or business
       • Only the external IP addresses need to be unique, the internal computers are not directly accessible