1.4 Wireless and wired networks JM

1.4 Wireless and wired networks JM

1. Networks

   • LAN (Local Area Network)
     • Computers are connected over a small geographical area such as a single building or a single site
     • Examples are Home network or home network
     • Has its own infrastructure of cabling and network hardware due to distance and practicalities
   • WAN (Wide Area Network)
     • Computers are connected over a large geographical area. This could be several buildings/sites, town wide, country wide
     • The biggest WAN is the internet
     • Uses external hardware and external infrastructure e.g. use of satellites, phone lines or the internet
   • Network Interface Card (NIC)
     • A network interface card allows a computer to connect to wired network
     • A NIC allows data packets to travel to and from a computer
     • Contains MAC address which is a physical hardware address
     • Allows an Ethernet cable to be plugged in

2. Network Setup

   • Client Server
     • Relies on central server
     • All clients (Devices) request services from the server
     • Additional hardware would be needed e.g high end powerful servers
     • All files stored centrally on a client server.
     • Workers can access files from any computer
     • All computers can update central database
     • Easily backed up and automatic
   • Peer-Peer
     • All computers have equal status
     • Each device can act as a client and a server
     • All devices can request and provide network services
     • No additional hardware / software needed to set up this type of network
     • Files are stored on their own computers, so the users have to login on the same computer every time
     • Users are responsible for backing up their own files

3. Packets

   • Is data that is transmitted over a network and is broken down into packets.
   • Contains Ip address of receiver and sender
   • Contain a sequence number
   • Have a life span( How many hops they can take before disappearing)

4. Network devices

   • Router
     • An interconnection device used on networks to connect two or more devices
     • Stores packets common routes
     • Examines IP addresses
     • Sends packets to hosts
   • Switch
     • If two or more computers place a packet onto a network at the same time a data collision occurs
     • A switch is an interconnection device that connects two or more devices together and helps in solving data collisions
     • As a data packet arrives at the switch - its destination address is examined and the switch creates a direct connection to that device