Module 3
Networks
Small Networks
Personal Area Network (PAN)
A network organised around an individual or a couple of individuals within the range of a few metres. It is a
mobile network and goes wherever you go as you carry your devices. For example, wireless earphones
connected to your phone.
A PAN automates connections between mobile devices. For example, when you connect your smartphone with
wireless headphones, the next time the headphones are switched on and in range, it will automatically be
connected again. (This is an advantage of a PAN – it automates connections).
Disadvantages of a PAN:
• Limited/short range.
• Data transmission may be slow.
• Peripheral devices (speakers, smartwatches, etc.) can usually only be paired with one device at a time.
Home Area Network (HAN)
A small network within a home environment that connects devices like computers, printers, gaming devices,
etc.
Advantages of a HAN:
• Users can access and share their data from any computing device in the home.
• Users can save money by sharing devices like printers.
• An internet connection can be shared by all devices in the home.
Disadvantages of a HAN:
• If the HAN is setup wirelessly, security is an issue that must be addressed (using passwords etc). If this
is not done, anyone in range can connect to the network an access files or use the internet connection.
Local Area Network (LAN)
This is a network which connects computers in a small area such as a school, university campus, etc. Most LANs
use both wired and wireless connections. The term WLAN indicates that at least part of the network is linked
wirelessly.
Advantages of a LAN:
• Files are stored on a central computer (file server) allowing users access from any computer in the
network.
• Files can be transferred without the use of devices such as portable hard drives.
• Software applications can be shared by users.
• Hardware such as printers can be shared by users.
• Security in the network can be controlled, ensuring that users only have access to certain files and
applications.
• A single internet connection can be shared by users.
1
, • It is easier to keep software like anti-virus software up to date using a network, as it can be done from a
central computer.
• From a teaching point of view, you can get software which allows you to broadcast to all computers in
the classroom.
• Internet access can be monitored and controlled as all the users must connect through a central (proxy)
server.
Disadvantages of a LAN:
A LAN can be expensive to install and maintain.
• A network administrator is necessary to manage the network.
• Network security must be maintained to ensure that the data on the network is kept secure.
• If the file server is faulty, nobody can access their files.
If a WLAN is used, the following disadvantages also apply:
• Sending data wirelessly is less secure than using cables.
• Performance can decrease as the number of computers increase.
• Signals could get lost or interfered with due to electronic or electrical interferences.
Intranet
An organisation’s private network and is an internet-like environment consisting off web pages relating to the
organisation’s business. The information stored on the intranet is only available to the organisation’s
employees. It can be used to publish organisation documents like policies, newsletters, training manuals, etc.
Larger Networks
Metropolitan Area Network (MAN)
A Metropolitan Area Network (MAN) is a network that connects multiple local area networks (LANs) across a
city or large geographic area.. It is typically used to link businesses, government offices, or academic
institutions within a metropolitan region.
Wide Area Network (WAN)
A network spread over a wide geographical area, such as a city, country, or continents. The purpose of a WAN is
to facilitate the sharing of resources and electronic communication of a wide geographical area.
Examples of WANs include the networks of businesses like Pick n Pay that link their shops in the country, The
Internet (although this is also referred to as a GAN – Global Area Network).
Global Area Network (GAN)
A Global Area Network (GAN) is a worldwide network that connects multiple networks, such as LANs or WANs,
across different countries or continents. It supports communication and data exchange on a global scale. The
Internet is an example of a GAN.
Setting up a Network
A network consists of the following components:
• Hardware
• Communication/Connection method
• Network software (used to control security and communication)
The following hardware are needed to set up a network:
2
, Hardware
Computers and Peripherals
Hardware in a network, includes the computers and devices linked in the network. The three general terms
used for computers linked in a network are:
• Workstations – A desktop computer connected to the network.
• Client – Has a broader meaning and refers to computing devices that can interact with the network and
use the networks resources.
• Server – A powerful computer that provides shared resources to network users. It is not used as a
‘user’ computer or a workstation. It will have better hardware specifications such as more memory and
larger hard drive space.
Examples of servers:
• File Server
The most common type of server. It is used to store files. The user sees it as H: drive and U: drive.
Advantages are that users can access these files from any computer on the network and they don’t have
to worry about backing up these files themselves.
• Email Server
Used to handle all the email needs of the organisation.
• Internet or Proxy Server
Allows security control for viruses and internet usage monitoring. All traffic between the internet and
the network pass through this server. Internet access can be sped up by storing (caching) recently
accessed web pages on disk.
• Web Servers
Used to host websites, e.g., for an organisation’s intranet.
• Print Servers
Used to handle all printing requirements of a network with many computers and printers.
• Database Servers
Provide access to data stored in a central database.
Large companies or organisations (where thousands or users request information per second) use many
servers working together to provide information requested. These are called server farms or data centres.
In smaller organisations, the same server might be used to perform multiple roles, e.g., to act as both a file and
print server.
‘Thin’ Client – A special cheaper type of computer that doesn’t have its own hard drive and has limited
memory and CPU power.
Switch
A device that is used to connect computers in a network with cables so that
communication can occur between computers – but it’s not used for internet access.
All devices in the network connect to the switch which allows them to communicate
with each other.
3
Networks
Small Networks
Personal Area Network (PAN)
A network organised around an individual or a couple of individuals within the range of a few metres. It is a
mobile network and goes wherever you go as you carry your devices. For example, wireless earphones
connected to your phone.
A PAN automates connections between mobile devices. For example, when you connect your smartphone with
wireless headphones, the next time the headphones are switched on and in range, it will automatically be
connected again. (This is an advantage of a PAN – it automates connections).
Disadvantages of a PAN:
• Limited/short range.
• Data transmission may be slow.
• Peripheral devices (speakers, smartwatches, etc.) can usually only be paired with one device at a time.
Home Area Network (HAN)
A small network within a home environment that connects devices like computers, printers, gaming devices,
etc.
Advantages of a HAN:
• Users can access and share their data from any computing device in the home.
• Users can save money by sharing devices like printers.
• An internet connection can be shared by all devices in the home.
Disadvantages of a HAN:
• If the HAN is setup wirelessly, security is an issue that must be addressed (using passwords etc). If this
is not done, anyone in range can connect to the network an access files or use the internet connection.
Local Area Network (LAN)
This is a network which connects computers in a small area such as a school, university campus, etc. Most LANs
use both wired and wireless connections. The term WLAN indicates that at least part of the network is linked
wirelessly.
Advantages of a LAN:
• Files are stored on a central computer (file server) allowing users access from any computer in the
network.
• Files can be transferred without the use of devices such as portable hard drives.
• Software applications can be shared by users.
• Hardware such as printers can be shared by users.
• Security in the network can be controlled, ensuring that users only have access to certain files and
applications.
• A single internet connection can be shared by users.
1
, • It is easier to keep software like anti-virus software up to date using a network, as it can be done from a
central computer.
• From a teaching point of view, you can get software which allows you to broadcast to all computers in
the classroom.
• Internet access can be monitored and controlled as all the users must connect through a central (proxy)
server.
Disadvantages of a LAN:
A LAN can be expensive to install and maintain.
• A network administrator is necessary to manage the network.
• Network security must be maintained to ensure that the data on the network is kept secure.
• If the file server is faulty, nobody can access their files.
If a WLAN is used, the following disadvantages also apply:
• Sending data wirelessly is less secure than using cables.
• Performance can decrease as the number of computers increase.
• Signals could get lost or interfered with due to electronic or electrical interferences.
Intranet
An organisation’s private network and is an internet-like environment consisting off web pages relating to the
organisation’s business. The information stored on the intranet is only available to the organisation’s
employees. It can be used to publish organisation documents like policies, newsletters, training manuals, etc.
Larger Networks
Metropolitan Area Network (MAN)
A Metropolitan Area Network (MAN) is a network that connects multiple local area networks (LANs) across a
city or large geographic area.. It is typically used to link businesses, government offices, or academic
institutions within a metropolitan region.
Wide Area Network (WAN)
A network spread over a wide geographical area, such as a city, country, or continents. The purpose of a WAN is
to facilitate the sharing of resources and electronic communication of a wide geographical area.
Examples of WANs include the networks of businesses like Pick n Pay that link their shops in the country, The
Internet (although this is also referred to as a GAN – Global Area Network).
Global Area Network (GAN)
A Global Area Network (GAN) is a worldwide network that connects multiple networks, such as LANs or WANs,
across different countries or continents. It supports communication and data exchange on a global scale. The
Internet is an example of a GAN.
Setting up a Network
A network consists of the following components:
• Hardware
• Communication/Connection method
• Network software (used to control security and communication)
The following hardware are needed to set up a network:
2
, Hardware
Computers and Peripherals
Hardware in a network, includes the computers and devices linked in the network. The three general terms
used for computers linked in a network are:
• Workstations – A desktop computer connected to the network.
• Client – Has a broader meaning and refers to computing devices that can interact with the network and
use the networks resources.
• Server – A powerful computer that provides shared resources to network users. It is not used as a
‘user’ computer or a workstation. It will have better hardware specifications such as more memory and
larger hard drive space.
Examples of servers:
• File Server
The most common type of server. It is used to store files. The user sees it as H: drive and U: drive.
Advantages are that users can access these files from any computer on the network and they don’t have
to worry about backing up these files themselves.
• Email Server
Used to handle all the email needs of the organisation.
• Internet or Proxy Server
Allows security control for viruses and internet usage monitoring. All traffic between the internet and
the network pass through this server. Internet access can be sped up by storing (caching) recently
accessed web pages on disk.
• Web Servers
Used to host websites, e.g., for an organisation’s intranet.
• Print Servers
Used to handle all printing requirements of a network with many computers and printers.
• Database Servers
Provide access to data stored in a central database.
Large companies or organisations (where thousands or users request information per second) use many
servers working together to provide information requested. These are called server farms or data centres.
In smaller organisations, the same server might be used to perform multiple roles, e.g., to act as both a file and
print server.
‘Thin’ Client – A special cheaper type of computer that doesn’t have its own hard drive and has limited
memory and CPU power.
Switch
A device that is used to connect computers in a network with cables so that
communication can occur between computers – but it’s not used for internet access.
All devices in the network connect to the switch which allows them to communicate
with each other.
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