Download Gr11IT2013-2_1-Networks

Module 2.1 Networks – Activity
Activity
1.
Networks form an integral part of modern ICT solutions.
Give a concise definition of a computer network.
1.
A network is a collection of computers or other computing devices (such as smartphones) that
are connected by some sort of communication media.
2.
One of the main aims of or reasons for using networks is to provide resources.
Give three broad categories or types of resources that can be shared via networks.
2.
Software, hardware, data and information.
3.
Give two aims or benefits of networks, besides the sharing of resources.
3.
Fast and efficient communication, centralisation of data, leisure, etc.
4.
Name the two broad categories of communication media or ways of connecting equipment in a
computer network.
4.
Cabled or wireless.
5.
A NIC plays a vital role in a network.
a)
Briefly explain the role performed by a NIC in terms of a network.
a)
A NIC is used to encode or ‘convert’ the data so that the data can be transmitted over a
specific medium and it decodes the data that is received.
b)
How would a NIC for a wireless network differ from a NIC for a cabled network?
b)
A NIC in a wired or cabled network will need a port to connect to a cable. In the case of a
wireless network, one needs a NIC with a small antenna that allows it to send and receive
data using radio signals.
c)
Most NICs are on-board.
Briefly explain what this means and what benefit this provides.
c)
The NICs are built into the motherboard so you don’t need to buy a separate physical
card to plug into the motherboard or a NIC that connects to a USB port.
d)
One will often see a NIC advertised with specifications such as
10 Mbps / 100 Mbps / 1000 Mbps
Explain what these specifications refer to and why there seem to be three different
specifications for the same item’.
d)
This refers to the data transmission speeds that the NIC can support, i.e. 10 Mbps, 100
Mbps and 1000 Mbps. The reason why multiple speeds are listed is that the maximum
transmission speed that can be used depends on the type of cabling and other
equipment, such as switches, used in the network. The NIC automatically detects and
operates at the fastest speed the network supports.
1
6.
7.
8.
Some adverts for NICs indicate specifications such as 802.11g and 802.11n.
a)
What does the ‘802.11’ indicate in terms of the NIC?
a)
It is a wireless NIC.
b)
Will an 802.11g NIC always be slower than an 802.11n NIC? Briefly motivate your answer.
b)
The 802.11n standard has a maximum capability of 50 Mbps as opposed to the 10 Mbps
capability of the 802.11g standard and therefore the 802.11n standard is faster. However,
one needs to remember that when you use a mixture of wireless equipment running at
different speeds, the speed is determined by the slowest component (transmission
speed).
Wired media consists of physical cables that connect devices and allow the devices to
communicate. The two main options used are UTP and fibre optic cables.
a)
What are the two main advantages of UTP cables as opposed to fibre optic cables?
a)
UTP cables cost less and are easier to install.
b)
What are the two main advantages of fibre optic cables as opposed to UTP cables?
b)
Fibre optic cables support higher speeds and have a greater bandwidth than UTP cables.
The signal also does not degrade over a distance in the same way that the signal of a UTP
cables does.
A local school is installing a LAN and they have been advised to use a star topology, a switch and
several hundred metres of UTP cabling to implement the LAN.
a)
Briefly explain what a LAN is.
a)
A LAN is a network that connects the computers in a small area such as a school,
university campus or company offices in one building to one another.
b)
What is the difference between a LAN and a WLAN?
b)
A wireless LAN (WLAN) is simply a LAN which uses wireless technology (radio waves) to
communicate rather than cables.
c)
What is meant by the term topology?
c)
The term topology refers to the layout of the physical connection of the computers in a
network.
d)
The principal was shocked that so much cabling is required as the school is only 160m in
length.
Explain why so much cabling is required by referring to the design of a star topology
network.
d)
In a star topology network every computer or device is connected via its own cable to a
central device and therefore a lot of cabling is required.
e)
What are the two main advantages of using a star topology?
e)
A star topology means the central device can direct traffic from sender to receiver
without having to broadcast to all the other devices on the network. It also means that if
a single cable fails, then only the device on the other end of that cable has to be
disconnected from the network.
2
9.
f)
Give the two main functions of a switch in a star topology network.
f)
A switch is used to connect computers in a central location to a network so that
communication can occur. It also directs the traffic between devices connected to the
switch.
g)
Explain how a router differs from a switch by referring to its function.
g)
A router makes communication between different networks (such a LAN and the
Internet) possible by helping to direct data to its correct destination.
A modem is a key component in data communications.
a)
Briefly explain the function of a modem in data communications.
a)
A modem converts the data or signal from a computer to a format that can be
transmitted over a communication channel such as an ADSL line.
b)
What type of network would make use of a 3G modem?
b)
A cellular network.
10. Why are access points necessary in a wireless network?
10. They allow devices to join the network using WiFi technology and they also allow radio (or
wireless) communication to take place between devices.
11. Give the main advantage and the main disadvantage of a wireless LAN compared to a cabled
LAN.
11. Advantage: It is easier to add devices to the network, cables are not necessary and wireless
LANs allow mobility, etc.
Disadvantage: The data transmission over a WLAN is slower than over a cabled LAN.
12. Your principal is at a conference overseas and wants to e-mail some documents back to the
school. He was advised to use the hotspot in the hotel from his smartphone.
Briefly explain what a hotspot is and how he can make use of this to gain access to the Internet.
12. Many restaurants, hotels, airports and shopping malls provide WiFi connectivity as a service.
The WiFi connectivity is sometimes referred to as a ‘hotspot’ or an ‘access point’. Most WiFi
hotspots are protected by a password. He may need to ask for the password in order to connect
to the Internet via WiFi and he may also need to pay by the hour for the service.
13. Your friend has installed an ADSL connection at home. Her father connects to the Internet via
3G when she is using the ADSL line.
Explain how the ADSL connection can be shared to save money.
13. Most ADSL modem/routers have WiFi capabilities. This means you can set up a WiFi connection
at home that allows your mobile devices to use the faster, cheaper data provided by your home
Internet connection instead of using the more expensive data from a 3G cellular modem. The
first time that you connect a device to WiFi, it will ask you to enter a password and thereafter it
will connect to the WiFi network automatically whenever the network is in range.
14. What do WiFi and WiMAX have in common and what are the two main differences between
these technologies?
14. They both allow wireless devices to communicate with one another.
3
WiMAX is an upgrade of WiFi technology and it allows wireless devices to communicate with
one another over a wider area than WiFi. It is also more secure than WiFi.
15. If WiFi is cheaper and easier to use, why do people bother using 3G connectivity?
15. The problem with WiFi is that it has a limited range and capacity and needs a cabled network to
connect to the Internet.
16. What do the following have in common?
EDGE, 3G, HSDPA, HSDPA+ and 4G (LTE)
16. They are all cellular technologies.
17. Give two devices that you can use to connect to a 3G network.
17. You can use a cellphone or a 3G USB modem with your computer.
18. What is the name given to the cellular (mobile) technology that is taking over from 3G and that
can operate at speeds of up to 100 Mbps?
18. 4G (also known as LTE).
19. Arrange the following types of network in ascending order with regard to their size:
LAN, PAN, WAN and HAN
19. PAN, HAN, LAN and WAN
20. What type of network does one typically set up and use to exchange files wirelessly between
two people on the playground at break time using Bluetooth?
20. PAN
21. Skype is probably the most popular form of VoIP software.
Briefly explain what VoIP is (the meaning of the acronym is not required).
21. VoIP is a protocol that allows telephone (or voice) calls to be made over networks.
22. Skype and other VoIP software is generally free. Give two other advantages of VoIP in general.
22. VoIP calls are cheaper than normal telephone calls.
VoIP allows you to transfer files, as well as make video conference calls.
23. Give two reasons why it is not necessarily a good idea to use video when making a call on
Skype.
23. The quality of the video may be poor if you have a slow Internet connection and you can quickly
use up your data cap.
24. The school would like learners and teachers who have Internet access to be able to ‘use’ the
school’s network from home. They have been advised to make use of a VPN.
Briefly explain what a VPN is.
24. A Virtual Private Network (VPN) is a way of allowing access to a network with the same privacy
and security as a LAN, but by using Internet connections to do so.
25. Geotagging refers to the process whereby geographical coordinates are added as ‘metadata’ to
media such as photographs and video.
Which type of technology would be used to generate the physical location of where a
photograph was taken?
4
25. GPS (Global Positioning System) technology
5