What is a network?
A network consists of a number of computers linked either by cable or wireless
technology.This allows computers on a network to share resources including
hardware and software.Computers on the network can also communicate with each
other
.
A standalone computer is not connected to a network
LAN and WAN
A computer network can be either LAN or WAN
LAN (Local Area Network)
● Spread over a small geographical area such as a single
building
● Allows for very high speed transmissions with
low error rates
WAN (Wide Area Network)
● A series of connections covering a large
geographical area such as the world or a country
or a city
● Allows for wide area communication but has
many connections so can be slow
WAN
The computers in a WAN are connected by a telecommunications link, such as the
public switched telephone network (PSTN).
A Wide Area Network is likely to be composed of several LANs connected together
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Advantages of using an WAN
● Have the capability of accessing a vast and diverse range of multimedia
resources and services.
● Retailers can use e-commerce websites to sell their products to a worldwide
market 24/7.
● Users are able to use their access to manage bank accounts, shop online and
communicate instantly with anyone
Disadvantages of using an WAN
Security Concerns
-data theft
-denial of service attacks
-Spamming
-hacking
LAN
This allows a range of devices to be on a LAN at the same time, for example tablets,
PCs and laptops could all connect to the same network.
A LAN may be connected to a WAN, for example computers within a school could be
connected to the internet
Advantages of LAN
● Computers can share peripherals such as printers and scanners.
● This reduces the cost of buying and maintaining peripherals.
● Programs can be stored on the network’s file server, allowing computers on
the network to share software.
● When an authorised user logs onto any computer on the network, they can
access their own files, allowing flexible access from multiple locations
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Disadvantages of LAN
Networks and organisations would need to consider the costs.
★The initial costs of purchasing and installing file servers, network cabling and
peripherals can be expensive.
★A member of staff may need to be hired and trained to act as a network
manager.
★If the file server is damaged or breaks down, those files become inaccessible.
★Network security as a virus could spread to all computers through the
network.
WWW
Although the internet and the World Wide Web (WWW) are separate
technologies,they work closely together .The internet is an example of WAN,which
allows information to pass between computers linked to a global network;it is a
method of transporting data
The WWW is an implementation which uses the internet.Sometimes it can be
referred as The Internet.
-WWW was invented by Sir Tim Berners-Lee
-Internets were invented by DARPA
-WWW allows for creation and accessing of web pages using HTML and HTTP
● A website has a unique address, known as its URL (uniform resource locator).
● Each website consists of a number of web pages developed using a web authoring
language - HTML (hypertext markup language).
● Web pages are connected using hyperlinks, and the first page is called the ‘home
page’.