Networks
Disadvantages
Concept
Advantages
It allows us to communicate from a device with other network users and join their communities.
Makes it easy to share files, data and resources (printers and internet connections).
It is also a very efficient way to store data centrally, easy access and back-up
A network consists of two or more computers that are linked together.
Access different forms of entertainment
Make use of on-line services such as shopping (e-commerce) or banking
Vulnerable to virus
If the network breaks, many tasks become very difficult
Easy for hakers to enter your system
Networking Hardware
Hub
Switch
Network Cable
Network Interface Card (NIC)
Router
Proxy Server
Bridge
Firewall
Modem
It is a computer setup useful to share a resource, usually an Internet connection.
Cables are better than wireless, because they can carry much more data per second, and are less open to hacking.
Necessary in any computer that is connected to a network.
Device that connects a number of computers together at the centre of a star network to make a LAN.
Can be connected through cables, telephone lines, radio waves, satellites, or infrared light beams
In order to exchange data, share resources and communicate.
Same functions but more ‘intelligent’ device than a hub: if it receives a message, it checks who it is addressed to, and only sends it to that specific computer.
Connects together two or more networks.
A common use is to join a home or business network (LAN) to the Internet (WAN).
Typically links together two different parts of a LAN.
Device or piece of software that is placed between your computer and the rest of the network. Protects from hackers.
Device that joins the digital computer to the analogue telephone line.
contains a DAC and an ADC.
DAC
required so that the digital computer can send data down the analogue telephone line
ADC
required so that the analogue signals (noises) that arrive via the telephone line can be converted back into digital data.
Types of network
WAN (Wide Area Network)
MAN (Metropolitan Area Network)
LAN (Local Area Network)
WLAN (Wireless Local Area Network)
Network confined to one building or site.
Often a private network belonging to an organisation or business.
Network that extends over a large area, often created by joining several LANs together.
network that connects computers within a metropolitan area.
A wireless LAN (WLAN) uses radio signals (WiFi) to connect computers instead of cables. More convenient but difficult to make secure.
Network Topologies
HIBRID
STAR
BUS
Network where every computer is connected to a central device that passes messages between computers.
RING
network where each computer is connected to a loop of cable; 'the ring'
Network that combines two or more of BUS, STAR and RING basic topologies.
Network where a long, central cable, (the ‘bus’) is used to connect all of the computers together.
Internet, Intranet, and Extranet.
Intranet
Extranet
Internet
Provides the network connections that links computers together.
private network (only for the users of the intranet) that provides similar services to The Internet
private network that enterprises use to provide trusted third parties
used for
Sharing files
Sending and receiving e-mail messages
View web pages on the WWW (World-Wide Web)
Communicate using voice and video conferencing
Commonly used by businesses for
Internal e-mail and instant-messaging between workers
Sharing of internal documents
Viewing internal web pages
such as
Vendors
Partners
Suppliers
Customers
Other services
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