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NETWORKS Florencia Adúriz and Celina Doucet - Coggle Diagram
NETWORKS
Florencia Adúriz and Celina Doucet
What is a network?
A way to connect two or more computers to exchange data
Disadvantages
Use of internet
Information isn't always reliable
Some websites are dangerous
We become too dependant of them
Viruses
Vulnerability to hackers
Advantages
Use of internet
Access to online services
Easy access to information
Entertainment
Joining communities
Communicating
Keepings settings centrally
Sharing files and data
Storing data
Created using
Cables (wires)
Radio signals (wireless // wi-fi)
Telephone lines
Satellite links (for long distance)
Types of network
WLAN
W
ireless
L
ocal
A
rea
N
etwork
Uses radio signals (wi-fi) instead of cables
A wireless router sends and recieves data of the WLAN
More convinient than LANs
More difficult to make secure (important to have a good password)
LAN
L
ocal
A
rea
N
etwork
Used for a building or site
Private (usually belongs to a buisness)
Usually uses cables
WAN
W
ide
A
rea
N
etwork
Connects geographically distanced devices
Created by joining several LANs
Connection technologies
optical fiber cables
satellite and microwave radio links
Most common example: INTERNET
MAN
M
etropolitan
A
rea
N
etwork
A network installed to connect devices inside a city
Network topologies
Bus
A central cable which connects several computers together
All of the computers are linked to the central cable by a short cable
Slow but cheap to install
Stops working if the central cable brakes
Ring
Computers are connected by a cable which is in loop (like a bus cable which's ends are joined)
Doesn't suffer a break in the cable because computers are still joined
Star
Computers are connected to a central device
Central device = Hub (cheap, slow) or Switch (expensive, fast)
Expensive but very fast
Stops working if the central device breaks/gets damaged
Hybrid
Combines two or more topologies
Internet, intranet, extranet
INTERNET
Concept
World-Wide Network
The world wide web (www) is a part of the internet
Uses
Viewing web pages // Browsing the World Wide Web
Communicating via email
Sharing files
Playing online and multi-player games
Listening to streamed music
Watching streamed videos
Communicating using voice and video
Issues
A lot of exposure to hackers
When data is sent over the internet, being a public network, it could be viewed by unauthorised people
Bandwidth is not as good as in Intranet
INTRANET
Concept
A
private
network that provides similar uses as the Internet
Only accessible to members of the company which created it
Usually used by companies
Uses
Access to internal web pages and links
Internal e-mailing
Sensitive information is protected
Specific information for the needs of the company
Possibility to block websites
Issues
Isn't available for everybody
EXTRANET
Concept
An extended Intranet which is able to communicate and share information with people outside of the network while keeping its security.
Uses
Mainly by companies
To communicate and share information with providers, partners, sellers, clients, etc.
Issues
Although maintainign secure, opening up is a risk for Intranet networks
Network devices
Modems
Converts a computer's digital signal into an analogue signal for transmission over a telephone line, and viceversa
Mo
dulator
Dem
odulator
Hubs
Has several computers connected to it
recieves data from one and transmits it to the others
Makes a LAN network
Switches
Similar to a hub (has several computeres connected) but more efficient
Recieves a message from a computer and only sends it to the specific computer to which is adressed
Router
Example: Join a home/buisness (LAN) network to the internet (WAN)
Connects to or more networks
Can be wireless if the LAN network is wireless
Network Interface Card
Most computers have it built into the motherboard
Necessary for a computer to be connected to a network
Network cables
Secure (difficult to hack)
Can carry a lot of data per second
Bridge
Connects two different parts of LANs so they can function as one
Proxy Server
Sometimes replaces routers
A computer setup to share a resource
Usually Internet
Firewall
A device or software
Placed between a computer and the rest of the network
Protects the LAN from hackers
Blocks unauthorised connections