01 Section 2 - LANs, WANs and Hardware Flashcards
Define a LAN:
LAN : Local area network
-a network which covers a small geographical area
What are the features of a LAN?
- small geographical area
- all hardware is owned by the organisation that uses it
- they are wired or wireless
What are examples of places you would find LANs?
- businesses, schools, universities
- homes can have LANs which connect various devices such as PCs, tablets, smart TVs and printers
Why would you use a network?
- sharing files is easier
- share peripherals (e.g. printers…)
- internet connection can be shared between devices
- can install and update software on all computers at once
- can communicate with LAN users cheaply and easily
- user accounts can be stored centrally
How is sharing files made easier by having a network?
- network users can access the same files
- users can work collaboratively on them
- users can copy files between machines
Define a WAN:
WAN: Wide Area Network
-a network which covers a large geographical area, a network which connects LANs in different geographical locations
What are the features of a WAN?
- large geographical area
- organisations hire infrastructure from telecommunications companies (they own and manage the WAN)
- WAN is much more expensive than a LAN
- connected using fibre, copper telephone lines, satellite links, radio links
What are examples of places you would find WANs?
- businesses with offices in multiple countries require a WAN to connect the devices
- the Internet is the biggest WAN
What factors affect the performance of networks?
- the amount available of bandwidth
- wired connection are better than wireless (transmission media)
- choice of hardware
- choice of network topology
Define Bandwidth:
Bandwidth is the amount of data that can be transferred in a given time
-greater the bandwidth the higher the performance of the network
How can bandwidth affect the performance of a network?
- the more available bandwidth, the higher the performance
- too many users or heavy use may cause congestion and slow the network (to address this you can limit the available bandwidth to address this)
How can transmission media affect the performance of a network?
- wired connections are faster and more reliable
- fibre optic cables have better performance than copper cables
- wireless performance depends on signal quality
What factors affect wireless performance?
-wireless performance depends on signal quality, this is affected by range of device, interference from other devices and physical obstructions
What hardware do you need to create a network?
NICs
Switches
Routers
What does NIC stand for?
Network Interface Card
What is an NIC?
An internal piece of hardware that allows a device to connect to a network
Where is the NIC located on a computer?
- used to be on separate cards
- now built into the motherboard (they exist for both wired and wireless networks)
What is the purpose of a network switch?
To connect devices on a LAN
-switches receive data from one device and transmits this data to the device on the network with the correct MAC address
What are the units called which switches receive data in?
receive data in units called frames
What is the purpose of a router in a network?
They are responsible for transmitting data between networks (they are always connect to at least two different networks)
-they direct packets to their destination on the internet
Where are routers used?
-homes and offices to connect the LAN to the internet
Nowadays, what do most home routers consist of?
-router
-switch
-WAP
ALL IN ONE
What types of cables can be used?
Ethernet cables
Coaxial cables
Fibre optic cables
What are the two types of ethernet cables?
CAT 5e
CAT 6
What are the uses of cables?
to connect devices on a network
- Ethernet cables in a LAN
- coaxial and fibre optic for WANs
What are the features of ethernet cables?
- ‘twisted pair’ cables, contain four pairs of copper wires
- THEY ARE TWISTED TOGETHER TO REDUCE INTERFERANCE
What are the features of coaxial cables?
- single copper wire surrounded by a plastic layer for insulation
- metallic mesh provides shielding from outside interferance
What are the features of fibre optic cables?
- transmit data as light
- high performance and expensive cables
- don’t suffer interference
- can transmit over very large distances without loss of signal quality
What devices use radio waves to transmit data?
-mobile phones
-TVs
WIRELESS NETWORKS USE RADIO WAVES TO TRANSMIT DATA
What do you need to set up a wireless network?
A WAP device
What does WAP stand for?
Wireless Access Point
What is a WAP?
A switch that allows devices to connect wirelessly
What is a hotspot?
Hotspots are locations where you can connect to a WAP
What do devices need to connect to a WAP?
- need wireless capacity
- usually are built in, if not you can use a USB dongle
- HDMI dongles are popular for TVs
What is Wi-Fi?
The standard used for wireless networks
What are the two frequency bands of Wi-Fi?
2.4 GHz
5 GHz
What are the frequency bands of Wi-Fi split into?
Number channels that each cover a small frequency range
-these channels overlap
What affects the performance of a Wi-Fi network?
Interference
-interference between networks using adjacent channels affects performance
TO AVOID PROBLEMS, ONLY CERTAIN CHANNELS THAT ARE SPACED OUT TEND TO BE USED
