Networks

Networks

1. Advantages

   • Resource sharing - computers on the same network can share things like printers and connection.
   • The logins will be the same on each computer in the network.
   • Files will be available in all computers in the network.

2. Disadvantages

   • An error or virus may affect all computers in the system.
   • It is expensive and difficult to set up and maintain as it requires technical expertise.

3. Types of network

   • LAN (Local Area Network)
     • A network contained in a single geographical location or organization.
   • WAN (Wide Area Network)
     • A network spanning a wide geographical area, or multiple organizations.
     • Often consisting of many LANs networked together

4. Topologies

   • Bus topology
     • All nodes connected to one wire. High chance of both total failure and collisions, but very cheap.
   • Ring topology
     • All nodes connected to each other in a ring. High chance of failure, and hard to expand, but low chance of collisions.
   • Star topology
     • All computers are connected to a central switch. This topology has a low chance of catastrophic failure, and of collisions, but is expensive.
       • This is the most commonly used.
   • Mesh topology
     • Full mesh
       • A topology in which every single computer or node is connected to every other node.
     • Partial mesh
       • A topology in which some of the devices are connected to many devices, but other devices are connected only to a couple of devices.
     • This is the type of topology that the internet is, and if one cable is interrupted, an alternative route can always be found. This is why you can't take down the internet.

5. IP addresses

   • An IP address is a unique value assigned to every computer on a network, used to identify it - like a house address. It is written in binary code, and changed to strings of numbers separated by dots to read.
     • 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.
     • When the format of IP Addresses were decided in 1983, 4,228,250,625 addresses seemed more than enough.
       • Globally, there are now more devices on the Internet than the devices it’s possible to assign a unique address to. We fix this this by assigning an “external” IP address to each house or business, then “internal” IP addresses to the computers in that house or business .
         • For example, in order to get around there not being enough addresses, the school only has one IP address.