network

network

1. advantages

   • share files
     • same files availible
     • same files on each computer
   • share resource
     • share printers
     • internet connections
   • share logins
     • same username and password

2. disadvantages

   • expensive
     • specialist needed
     • expensive hardware
   • risk increased
     • viruses can effect every computer
   • difficulty
     • expertise needed to set up and maintain

3. types of network

   • LAN
     • local area network
   • WAN
     • wide area network

4. bus

   • The network consists of a single cable that runs through the network
   • this attaches all devices to this cable

5. ring

   • 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

6. IP adrresses

   • The IP Address is unique value assigned to each computer on a network
   • Each IP address on a network must be unique
   • The IP Address is a 32-bit binary value
   • IP Addresses therefore range from 0.0.0.0 to 255.255.255.255 (255 is the biggest number that can be represented by 8 binary bits)
   • When the format of IP Addresses were decided in 1983, 4 billion addresses seemed more than enough
   • The Internet is a world-wide network Devices on the Internet need IP Addresses, just like any other network
   • This means it’s made up of 32 1s and 0s Example: 00110101000110100110011010111011 While binary is perfect for a computer to use, it’s a pain for humans to use, so we convert it binary to decimal 8 bits at a time

7. packets

   • Data is split into small chunks called packets
   • Each packet is sent along the lowest cost route
   • The packets are re-assembled on the other side

8. internet

   • packets
   • mesh
     • Rather than using a star, bus or ring topology, each node is connected to one or more other nodes in an ad-hoc manner
     • The layout of these nodes is called a Mesh Topology
     • In a mesh topology, there is excellent resilience to outages as messages can take many different routes to reach a destination
     • If any node or connection becomes unavailable, the message can simply take a different route