unit 1 and 2 revision

unit 1 and 2 revision

1. networks

   • LAN
     • connected in a small geographical area (Local Area Network)
   • WAN
     • connected in a large geographical area (Wide Area Network)
   • WPAN
     • a wireless personal area network, blue tooth is an example of the technology used (Wireless Personal Area Network)

2. connection types

   • Bluetooth is short ranged wireless interconnection of mobile phones, computers and other electronic devices
   • WiFi is when devices (computer, smartphones +more) connect to the internet or communicate with one another wirelessly within a particular area.
   • Ethernet is a cable connecting to a LAN (local area network)
   • GPRS is a packet based wireless communication service that promises data rates from 56 to 114 kbps (General Packet Radio service)

3. Network hardware

   • router
     • a device that forwards data packets along networks. it is mostly connected to a LAN or a WAN
   • switch
     • is a device in a computer network that connects other devices together. data cables are plugged into a switch to enable communication between different network devices
   • ethernet cable
     • faster data speed compared to WiFi,it has a range of 100 metres
   • WiFi extender
     • a device that repeats the wireless signal from your router to expand its coverage.

4. network hardware

5. network threats and security

   • firewall
     • controls which programs can send or receive data packets from your computer or network
   • antivirus
     • scans your computer periodically for malware.
   • passwords
     • needs to be 8 characters long and not hard to guess so hackers cannot guess it easily and get your details
   • encryption
     • scrambles data packets using a cipher so they cannot be read by unauthorised users

6. computer hardware

   • CPU
     • Fetches decodes and executes instructions
   • RAM
     • a computer memory that can be accessed randomly
   • Virtual Memory