1.4 Networks 1: LANs and WANs Flashcards
computer network
a group of computer systems and other devices linked together so that they can communicate and share resources such as printers
LAN
local area network
exists within a small geographical area on a single site
managed by a local manager or team at the site
hardware owned by the organisation using it
wired using UTP/copper cable, fibre optic or wifi
(many people have a home LAN allowing the people in a household to access the internet via a router)
WAN
wide area network
connect separate LANs over a large geographical area to form a network of networks
computers in a WAN can communicate with computers and users in other locations
infastructure is leased by the companies who own and manage it
connected by fibre optic, telephone lines, or satellite links
stand alone computers
computers not connected to a network
collective ownership
a WAN that is managed by several different people or parts of an organisation working together
distributed ownership
each LAN within a WAN is managed independently
list of factors affecting network performance
- bandwidth
- hardware and software/latency
- number of users
- high network traffic/error rate
-transmission media
bandwidth
the maximum amount of data that can pass through the medium per second
bits per second
not enough bandwidth for the data slows the network down
hardware and software/latency
hardware and software limitations (switches and routers) can affect performance
latency is caused by bottlenecks in the network, such as switches not being used to properly segment traffic
number of users
a lot of users can lead to network congestion, causing packets to be queued before they can be transmitted by routers and switches
too many users for the bandwidth slows it down
high network traffic/error rate
leads to collisions of data packets resulting in transmission errors
the packets have to be resent until they are received correctly
less reliable connections mean more errors
latency
delay from transmitting data to receiving it
transmission media
wired connections have a higher bandwidth than wireless ones; fibre optic cables have a higher bandwidth than copper cables
State one way in which a local area network and a wide area network are different [1]
a LAN is a network that is restricted to one building or site
a WAN is a network of separate LANs over a larger geographical area
A retailer wants to share data between its head office and its 300 high street stores
Explain why the business would use a WAN rather than a LAN for this purpose [2]
each shop would have its own LAN and these would be connected to form a WAN as they are spread over a large geographical area
a LAN isn’t used for larger areas
