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Unit notes and practice questions

Grade 9 Information Technology unit 2: Computer network

Everything here is for unit 2 of the Grade 9 Information Technology textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.

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5
Cards
10
Practice questions on unit 2
37–71
The textbook pages for unit 2

What unit 2 covers

  1. 1.Definition of Network
  2. 2.Fundamental Elements of Network
  3. 3.Types of Networks
  4. 4.Advantages and Disadvantages of Network
  5. 5.Unit Review Exercise

Short notes for unit 2

The cards filed under this chapter on the Grade 9 Information Technology page. Open one at a time.

FeatureClient-Server NetworkPeer-to-Peer Network
Central ServerDedicated server manages resourcesNo dedicated server, all peers are equal
SecurityCentralized high security on serverShare-level trust-based security
Node RolesClients request, server respondsEvery node can both request and respond
Cost and ScaleCostlier, stable for large networksCheaper, difficult if nodes exceed 10

When you use it

Use when contrasting network access models based on resource management, security, and hierarchy.

Watch out

In peer-to-peer, each computer is responsible for its own data. In client-server, security and files are centralized.

Drafted from Grade 9 Information Technology, pages 37-71, then checked twice before it went up

When you use it

Use when choosing between networking devices based on how they handle network traffic and addressing.

Watch out

A hub broadcasts data to all connected devices. A switch forwards data only to the destination port using physical addresses. A router connects different networks using routing tables.

Drafted from Grade 9 Information Technology, pages 37-71, then checked twice before it went up

DeviceNetwork RoleOperational Characteristic
NICConnects a computer to network mediumContains physical port or wireless antenna
RepeaterRegenerates and boosts weak signalsExtends network distance by cleaning noise
SwitchInterconnects devices within a LANUses physical address table to forward packets
RouterInterconnects different dissimilar networksUses routing table to find the best route
WAPBridges wireless devices to wired LANUses Wi-Fi or Bluetooth radio signals

When you use it

Use when identifying the function of hardware devices that connect, route, or regenerate data between hosts.

Watch out

A Switch creates a local network (LAN). A Router is required to connect different networks together.

Drafted from Grade 9 Information Technology, pages 37-71, then checked twice before it went up

Network TypeGeographical CoverageTypical Example
PANUp to 10 m10\text{ m}Bluetooth connected devices
LAN10 m10\text{ m} to 1 km1\text{ km} (building or campus)School laboratory or office
MAN10 km10\text{ km} to 100 km100\text{ km} (entire city)City-wide bank branch network
WAN1000 km1000\text{ km} to 10000 km10000\text{ km} (globe)The Internet

When you use it

Use when identifying or comparing network types based on physical distance and geographic coverage.

Watch out

Bluetooth is a PAN, not a LAN. The Internet is the prime example of a WAN.

Drafted from Grade 9 Information Technology, pages 37-71, then checked twice before it went up

TopologyPhysical LayoutMain AdvantageVulnerability / Point of Failure
BusSingle long backbone cableCheap and uses least cablingBreak in backbone disables whole network
StarDedicated link to central switchFault tolerant and easy to installCentral switch failure disables all nodes
RingCircular loop to two adjacent neighborsEasy fault isolationFailure of a single node disables whole ring
MeshDirect point-to-point link to every nodeMost secure and fault tolerantExtremely expensive and complex cabling

When you use it

Use when comparing network topologies by structure, cabling requirements, benefits, and failure behavior.

Watch out

In a Star network, one cable breaking affects only that computer, but switch failure breaks the entire network.

Drafted from Grade 9 Information Technology, pages 37-71, then checked twice before it went up

Practice questions on unit 2

10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.

Question 1

Connecting a laptop and a mobile phone using Bluetooth is an example of which type of network?

  1. A.Personal Area Network (PAN)
  2. B.Metropolitan Area Network (MAN)
  3. C.Wide Area Network (WAN)
  4. D.Global Area Network (GAN)
Show the answer and why

Answer: A Personal Area Network (PAN)

Why

A Personal Area Network (PAN) is organized around an individual person. A network created using short-range Bluetooth is a standard example of a PAN.

Question 2

Which wired communication medium uses light to transmit signals at faster speeds and longer distances?

  1. A.Unshielded twisted-pair (UTP) cable
  2. B.Fiber optic cable
  3. C.Coaxial copper cable
  4. D.Radio wave medium
Show the answer and why

Answer: B Fiber optic cable

Why

Fiber optic cable uses light pulses to carry data faster and across greater distances than copper cables.

Question 3

Which of the following is classified as an end device (host) in a network?

  1. A.Network Interface Card
  2. B.Switch
  3. C.Network printer
  4. D.Repeater
Show the answer and why

Answer: C Network printer

Why

An end device or host is a device that sends or receives data directly. Network printers, desktop computers, and laptops are end devices, while switches and repeaters are intermediary devices.

Question 4

In which network topology are all computers connected to a single central controller such as a switch?

  1. A.Star topology
  2. B.Ring topology
  3. C.Bus topology
  4. D.Mesh topology
Show the answer and why

Answer: A Star topology

Why

In a star topology, each device has a dedicated point-to-point connection to a central device, usually a switch.

Question 5

Which intermediary device regenerates a weak electronic signal to restore it to its original strength over long distances?

  1. A.Router
  2. B.Repeater
  3. C.Switch
  4. D.Wireless Access Point
Show the answer and why

Answer: B Repeater

Why

A repeater extends network distance limits by refreshing and regenerating weak electronic signals back to their original strength.

Question 6

A commercial bank in Addis Ababa connects three separate branch offices located across the city using the Ethio-telecom network. What type of network is created?

  1. A.Personal Area Network (PAN)
  2. B.Metropolitan Area Network (MAN)
  3. C.Local Area Network (LAN)
  4. D.Wide Area Network (WAN)
Show the answer and why

Answer: B Metropolitan Area Network (MAN)

Why

A Metropolitan Area Network (MAN) is designed to cover an entire city, such as connecting multiple bank branches across a city.

Question 7

In a peer-to-peer network, what is the maximum number of computers usually recommended so that administration does not become too difficult?

  1. A.5 computers
  2. B.10 computers
  3. C.50 computers
  4. D.100 computers
Show the answer and why

Answer: B 10 computers

Why

The textbook states that a peer-to-peer network usually does not exceed 10 computers because administration becomes very difficult beyond this number.

Question 8

What happens to a network with a star topology if the central switch breaks down?

  1. A.Traffic automatically passes through adjacent neighbor nodes.
  2. B.The network continues to work without any interruption.
  3. C.Only computers linked by fiber optic cables continue to send data.
  4. D.The entire network becomes defunct and stops functioning.
Show the answer and why

Answer: D The entire network becomes defunct and stops functioning.

Why

Because all devices in a star topology rely entirely on the central switch to send data to one another, the whole network fails if that switch goes down.

Question 9

How does a network switch differ from a basic hub when forwarding data packets?

  1. A.A switch broadcasts every packet to all ports, but a hub sends packets only to the destination port.
  2. B.A switch sends packets to a specific destination device, whereas a hub broadcasts received packets to all connected computers.
  3. C.A switch only uses light signals, whereas a hub only uses radio signals.
  4. D.A switch is an end device, whereas a hub is a communication protocol.
Show the answer and why

Answer: B A switch sends packets to a specific destination device, whereas a hub broadcasts received packets to all connected computers.

Why

A switch is intelligent and learns device addresses to forward packets to specific destination ports. A hub simply broadcasts all incoming packets to every connected device except the sender.

Question 10

Which device is designed to interconnect dissimilar networks simultaneously and uses a routing table to choose the best path for data?

  1. A.Router
  2. B.Network Interface Card
  3. C.Repeater
  4. D.Switch
Show the answer and why

Answer: A Router

Why

A router connects different networks and uses its routing table to determine the best path for forwarding data packets to their destination.

The app holds 12 questions on this unit, marked as you go. These are the first 10.

The textbook pages for unit 2

Unit 2 runs from page 37 to page 71 of the Ministry of Education edition.

Ministry of Education edition, English, 251 pages

Download the PDF

All Grade 9 Information Technology short notes

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