1.4 wired and wireless network

1.4 wired and wireless network

1. Network

   • LAN
   • WAN
   • Client-server
   • Peer-to-peer

2. WAN

   • Wide area network
     • Computers are connected over a large geographical area. This could be several buildings/sites, town wide, county wide or even country wide.
       • The biggest WAN would be a global collection of networks (known as the internet)

3. LAN

   • Local area network
     • E.G. Home network
       • School network
         • Network in a shop
     • Computers are connected via a small geographical area such as a single building or site

4. Client-server

   • The network relies on a server
   • All clients (devices) request services from the server
     • Additional hardware would be needed e.g. high end powerful servers
       • All files can be stored centrally
         • Workers can access files from any computer
           • All computers can update central databases
             • Individual computers do not need to be backed up
           • Backups are easily managed
           • All data is backed up in one go

5. Peer-to-peer

   • All computers have equal status
     • Each device can act as a client and a server
       • All computers are responsible for their own backup
   • All devices can request and provide network services
     • No additional hardware/software needed to set up this type of network
       • Files are stores on their own computers
         • users have to log into the same computer every time

6. Packets

   • Data transmitted over a network is broken down into packets
     • Each packet contains the address of the sender and the address of the receiver (IP address)
     • Packets will also contains a sequence number
       • Packets will have a time to live (how many hops around the network they can take before they disappear

7. Router

   • An interconnection device used on networks to connect two or more devices
     • Routers cotain a routng table which has a list of IP adresses and common routes for packets to take
       • Routers examine packets IP adresses
       • The router will apply a subnet mask to identify a network and determine whicvh network the packet should be forwarded too
         • If the packet is for this network - the router determines which host to send the packet to
           • Routers allow packets from different network types to be exchanged