Unit 1.4 - Wired And Wireless Networks Flashcards
Stand-Alone Pc
Computer that is
not connected
to any other device, network or the internet.
A Network
Two or More Computers connected together
Advantages of - Network
- Share Hardware (Printers) - - Share Files
- Log on anywhere
- Central Backups
- Central Virus checks
Disadvantages of - Network
- Viruses & Hackers
- Network Failure & Traffic
- Costs of Hardware &
Software needed - Expert Knowledge & Skills
needed
LAN
Local Area Network
Small geographical location
WAN
Wide Area Network
Large geographical location (Network of Networks)
A Switch
Links Computers and Peripherals in an LAN
Switch - Sends data only to device needed
A Hub
Links Computers and Peripherals in an LAN
Sends data to all devices
More Data Collisions, Slower Network, Cheaper, Security Risks
Network Interface Card (NIC)
Needed in Every Device / Peripheral to connect to a Network
MAC Address
Router
Receives, Forwards, Directs
data packets between Networks & Computer
Wireless Access Point
Links computers & peripherals Wirelessly
Modem
Modulator Demodulator
Converts analogue signals to digital and back again
Bridge
Connects two separate LAN Networks.
Relays data to receiving computer.
Server
Responds to request for data
Stores data used by other computers on a network
Ethernet
Twisted Pairs of Cables
Cat-5, Cat-5e, Cat-6
Cheap, Sturdy Short Distance (100m) & EMI/RFI Interference, Slower
Coaxial Cable
Insulated Central Wire
Braided wire shield to Prevent Interference
Cheap, Long Distances
EMI/RFI Interference
Fibre Optics
Glass Threads
Transmit Light as Data
Fast Bandwidth (10 Ghz), Secure,
Long Distance, No Interference
Expensive, Brittle
Client-Server Network
Client makes requests to the server for Data, Access & Programs.
Peer-to-Peer Network
All Computers are Equal
Peers download/share different parts of the same file.
Network/Wired Performance
Transmission Used (Fibre or Copper)
Number of Users
Bandwidth
Error Rate
Latency
Wireless Performance
Frequency Range
Channels Used / Sharing Channels
Distance from WAP
Physical Obstacles (Thick Walls, Metal)
Non-Wifi Interference (Microwaves, Cordless Phones)
Bandwidth
How much data can be transferred over a connection in a given time
Latency
How much Delay in sending and receiving bits.
Error Rate
How many data errors happen over a given time.
Sending a 0 instead of 1
Caused by Weak signals over longer distances
Or Electromagnetic / Radio Frequency Interference
The Internet
World wide collection of computer networks
DNS
A directory to match the URL (Domain Name)
with their IP address
Hosting
Websites stored on Dedicated Web Servers
The Cloud
Remote Web Servers used to store data and software accessed using a device on the internet.
The Cloud - Advantages
Cost - Less Hardware
Cost - Less Technical staff
Automatic Backup
Access Anywhere, Anytime
Any Device, Any OS
Software auto updated
Easy Collaboration
The Cloud - Disadvantages
Reliant to keep data Safe
Need Internet
Hackers & Attacks
Servers fail - No data
Business fails – data is lost
Virtual Network
Software based network
Divide Devices on a LAN in smaller groups.
VPN
Devices connecting remotely to a LAN using a secure connection ensuring data sent is Encrypted (Tunneling)
