Wide Area Networks Definitions, purpose and role internet as an example of WAN Internet services (uses, purpose, advantages, disadvantages, limitations, examples Real time messaging - instant messaging and chat Voice over Protocol (VoIP) File transfer Protocol (FTP) File sharing

1. Computer Applications Technology
Grade 12 – Term 2
Lesson 1

4. Wide Area Networks

5. Networks

6. • It is two or more computers and/or devices connected
together via a communication medium such as a cable or
wirelessly so that data and information can be shared.
• Two forms of network connections:
• LAN’s (Local Area Networks)
• WAN’s (Wide Area Networks)
What is a Network?
WPAN
WHAN
WLAN
WMAN
PAN
HAN
LAN
MAN

7. • LAN – Local Area Network.
• Computers connected in a LAN are connected over a
• short distance such as a
LAN – Local Area Network
• campus,
• office building,
• classroom etc.

8. What do you need to be connected in a Network?
•Hardware Devices (Computers/Printers)
•Communication media (Wired or wireless)
•Network Interface Card (on-board, or external)
•Network Software
SWITCH

9. • A WAN is a wide network of computers that is spread over a large
geographical areas such as cities, countries and continents.
• There are many communication media to connect a WAN
together.
• Some examples are:
• Cables
• Satellite
• Radio Waves
• Microwave
WAN (Wide Area Network)

10. •To facilitate communication between users
over large distances
•Share a centralised data source
•Connect LANs together (business network)
Purpose of a WAN

11. •Examples of WANs:
•Bank networks such as Nedbank or ABSA
(Offices in cities around the country)
•The Internet (which can also be referred to as
a GAN – Global Area Network)
Examples of WANs
International Network

12. • The Internet is a worldwide computer network
• that consists of
• computers and
• networks
• that are linked using
• phone lines,
• satellite,
• microwave and
• undersea cables
• in order to communicate and share resources.
The Internet

13. • The Internet is used every day by millions of
people in order to stay “in contact” with the
world around them.
• People use the Internet to:
• Communicate – via Email, Social Networks, Etc.
• Shop on-line
• Check weather
• Do business etc.
Getting Connected …

14. Revision Exercise on Networks
Explain in your own words what a network is?
• A Network is a two or more computers and/or devices
connected together using a communication medium such as
cables or wireless methods. (e.g. PAN)
Define the term LAN
• A LAN is two or more computers or devices connected
together over a short distance using a communication
medium. (e.g a school, university campus, office building)

15. What is needed to connect computers in a LAN?
 Computer or other device such as a printer
 Communication medium such as a cable
 Network Interface Card (NIC)
 Network Software

16. Define the term WAN
• A large network of computers that covers a large geographical
area like a city, province, country or continent.
Describe in your own words what the Internet is and what its main
functions are
• The Internet is a worldwide computer networks that consists of
computers and networks linked together using phone lines,
microwave, satellite or undersea cables.
• The main functions of the internet are:
• To facilitate communication
• Share resources

17. Besides using cables and radio waves to connect
computers in a WAN, name TWO other communication
methods.
 Microwave
 Satellite

18. Internet
Services

19. • The Internet and connectivity has become an integral part of modern live
• Access to the Internet means access to the services that the Internet
offers.
• The services have helped us to communicate via
• text,
• voice and
• video.
• It has changed the way we:
• process,
• store and
• share information.
Internet Services

20. • These are live, text-based communication facilities
that use computers or other devices to allow two or
more people to communicate with each other in real-
time. E.g.
•WhatsApp
•Google Chat
• BBM
•IM facilities are built into social networking sites
like Facebook
Real-time messaging

21. •Cost effective.
•send and receive an unlimited number of message for
free – by some services
•Chat in real-time with more than one person at a
time
•Let your contacts know if you’re available to chat
/Notifies the user when other users are online
•Some apps can be used on a variety of operating
systems such as iOS and Android
Advantages - Real-time messaging

22. •Can lead to anti-social behaviour
•Can create opportunities for
•cyber-stalking,
•cyber bullying and
•identity theft
•No control to ensure that people are
who they claim to be
Disadvantages & Limitations - Real-time messaging

23. • Converts voice sounds into data so that computers
and mobile devices can transmit it over the Internet.
• The software converts the sound into data packets
and sends it over the Internet like normal data is
transmitted. E.g. Skype
VoIP (Voice over Internet Protocol)

24. •VOIP calls are cheaper than normal phone calls
•Software is generally free
•Can transfer files as well as make video
conference calls
Advantages of VoIP

25. •Need an Internet connection
•Both users need to use the same software
•Call quality might be poor if the Internet
connection is slow
•Data cap is used up quickly when using
video.
Disadvantages & Limitations of VoIP

26. • This is when two or more people hold an online
conference (meeting) at different locations using a
network to transmit audio and video files.
• In order to hold a video conference you need:
• Webcam
• Microphone &
• Speakers
• Device
• Connectivity
Video Conferencing

27. Advantages Disadvantages/Limitations
• You can see the people
you’re communicating with
• Need a fast Internet
connection
• Much cheaper
• than normal calls or
• travelling/
• accommodation to the
meeting
• Need a lot of data
especially when using video
Advantages & Disadvantages/Limitations -
Video Conferencing

28. • This is a protocol used for the transfer of files between computers
that have an Internet connection.
• This includes uploading and downloading files.
• Files can be uploaded to an FTP server and then downloaded from
the FTP server
• FTP servers are dedicated servers that allow users to download or
upload files to or from the server.
• FTP servers use an FTP website as an interface between the user and
the server.
FTP (File Transfer Protocol)

29. Advantages Disadvantages/Limitations
• Large files can be transferred
easily without file size
restrictions
• End-users to not know how
to use FTP
• You can schedule the transfer
of a file to a time when the
network is not busy
• FTP connections can be
interrupted & the transfer will
have to be restarted
• Security is maintained using a
user name & password
• Not all companies have FTP
servers
• Can be quite technical
Advantages & Disadvantages/Limitations

30. •Web Browsers can be used to share and store files,
documents and photos on the Internet. This can be
done using specially designed websites like:
• DropBox
•SkyDrive
•SugarSync.
•Files can also be shared using email attachments.
File Sharing

31. Advantages of File Sharing
• Files are constantly synchronised so they will always be
updated
• Files can be stored and the link sent to a user via e-mail (this
will eliminate sending a large file via email)
• A limited amount of storage space is available for free – it’s
relatively cheap to pay for more storage space
• Files can be accessed from anywhere with Internet access
• No need for removable storage devices
• Saves space on your HDD

32. Disadvantages/Limitations of File Sharing
• No guarantee of privacy & safety
• Cannot access your files if there is no Internet
connection
• If your cap is reached you cannot access your data
• File management on a file-sharing website may be
more difficult that on your own computer

33. Summary Of Internet Technologies
Looked At Today!
•Real-time
•VOIP
•Video Conferencing
•FTP
•File Sharing

34. Homework – for today!
Open your textbook at the section covering
Networking in the Second term.
1. Read the chapter to re-inforce the
content we looked at
2. Make summaries of the important
concepts so that you will remember
them
3. Focus on Advantages and
Disadvantages for every concept

35. REFERENCES AND SITES TO VISIT
RESOURCES THAT NEED TO BE ACKNOWLEDGED:
• GAUTENG DEPARTMENT OF EDUCATION
• TECH TEACHERS
• BANDICAM FREE RECORDING SOFTWARE
SITES TO VISIT:
http://www.ecexams.co.za/
https://www.techteachers.co.za/