Flashcards in 1.4 Wired And Wireless Networks Deck (39)
What is a LAN?
A network connecting devices over a small geographical area, e.g. a school or business
What is a WAN?
A network connecting LANs in different geographical locations over a large geographical area, e.g. between 3 cities
What is the biggest WAN?
What does WAN stand for?
Wide area network
What does LAN stand for?
Local area network
Name 3 differences between LANs and WANs
LANs connect devices over a small geographical area, while WANs connect LANs over a large geographical area
All LAN infrastructure is owned by the company themselves, whereas WAN infrastructure is hired from telecommunications companies, who own and manage the WAN
LANs are connected wirelessly using WiFi or wired using Ethernet cables, while WANs are connected using copper telephone lines, satellite links, radio links or fibre optic cables
What are the advantages of using a LAN?
Users can communicate cheaply and easily with each other, e.g. with instant messaging
User accounts are stored centrally, therefore users can log in and access their files from any device on the network
Allows sharing of files and collaboration
Allows sharing of peripherals such as printers
Allows the sharing of the internet connection between every device on the LAN
Computers are managed centrally so software can be installed and updated on all computers at once
What are the disadvantages of using a LAN?
Managing a large network is complicated
Viruses which infiltrate the network infect all computers
How are WANs connected?
Using copper telephone lines, fibre optic cables, satellite links or radio links
How are LANs connected?
Wired (e.g. using Ethernet cables)
Wireless (e.g. using WiFi)
What factors affect the performance of a network?
Hardware (Wired/wireless, Copper cables/fibre optic)
What is bandwidth?
The maximum amount of data that can be transferred in a given time, e.g. 500 Mbps
How does bandwidth affect network performance?
The more bandwidth, the more data that can be transferred per second, therefore the better the network can perform:
Available bandwidth is shared between users of a network - too many/heavy use causes congestion and slow the network
Available bandwidth is shared between users of a network - too many/heavy use causes congestion and slow the network.
How can we address this issue?
By increasing the bandwidth
By limiting the bandwidth available to individual users
Which provides better network performance: wired or wireless connections? Why?
Wired - generally faster and more reliable
Greater bandwidth (up to 10 Gbps rather than up to 600 Mbps)
No interference with cables
What is a network?
A group of computer systems and other devices linked together so that they can communicate and share resources such as printers
Which provides better network performance: copper cables or fibre optic cables? Why?
Fibre optic - don’t suffer interference and can transmit over very large distance without loss of signal quality
Transmit signals at much greater speeds and over greater distances
What is wireless performance affected by?
Range of the device
Give an example of a physical obstruction
Thick walls in buildings
How do physical obstructions reduce network performance?
Prevent the transmission of data in wireless connections therefore decrease network performance
How does interference affect network performance?
Signals on adjacent channels interfere with one another and lower each other’s performance
What is the contention ratio?
The number of users : available bandwidth
What does a 100:1 contention ratio mean?
Up to 100 users can share the line at any time
What does a 1:1 contention ratio mean?
Only one user can make a connection on the line at any one time
What is the difference between CAT5e and CAT6 cables?
CAT6 cables are faster, and give a greater bandwidth
How does range affect network performance?
All signals have a maximum range (with 2.4 GHz signals having a greater range than 5), and as the limit is approached, performance decreases due to increased distance
How does high network traffic affect performance ?
Can lead to data package collisions, therefore loss of data and transmission errors – these packetsw have to be re-sent
What is an NIC?
Network Interface controller
An internal piece of hardware which allows the computer to connect to a network
Formats the data sent to and received by the computer
Where is the NIC found in a computer?
Is often built on chips in the motherboard