Chapter 11: Networks

Question 1

Transmission medium

Answer 1

Means of connecting two or more computers together, using copper cables, radio waves or light pulses, so that they may exchange data and interact with each other

Question 2

Computer network

Answer 2

ADVANTAGES
1. Shared resources 
2. Shared internet access 
3. Shared software
4. Shared storage 
5. Communication 
DISADVANTAGES
1. Initial costs 
2. Maintenance costs 
3. Security risks
4. Risk of data loss
5. Sever outage

Question 3

Types of computer networks

Answer 3

1. Local area network (LAN)
2. Metropolitan area network (MAN)
3. Wide area network (WAN)

Question 4

Local area network (LAN)

Answer 4

Network of computing devices connected within a small geographical area, typically within the same building, such as a house, school or office

Question 5

Metropolitan area network (MAN)

Answer 5

Network of computing devices typically spanning across two or more buildings within the same town or city

Question 6

Wide area network (WAN)

Answer 6

Network of computing devices covering a large-scale geographical area, typically across multiple geographical locations

Question 7

Ethernet

Answer 7

Most commonly used wired network protocol for local and metropolitan area networks

Question 8

Network protocol

Answer 8

Set of standards and rules that govern on how two or more devices communicate over a network

Question 9

Wired network

Answer 9

Network of devices connected by a physical medium, such as cables

Question 10

Wireless network

Answer 10

Network of devices in which signals are transmitted without the use of a physical medium

Question 11

Wireless access point (WAP)

Answer 11

Network hardware that provides a connection between wireless devices up to 100 metres away and can connect to wired networks

Question 12

Client

Answer 12

Computer that initiates a connection to a server to request for resources and services to perform operations

Question 13

Server

Answer 13

Computer that shares resources with and responds to request from devices and other servers on the network

1. Providing central storage of files
2. Sharing hardware such as printers
3. Controlling logins and network access

Question 14

Client-Server Network

Answer 14

ADVANTAGE
Centralised control of data and resources
DISADVANTAGE
Higher initial cost due to the need for a server

Question 15

Peer-To-Peer (P2P) Network

Answer 15

ADVANTAGE
Cheaper to set up as there is no cost related to dedicated servers
DISADVANTAGE
Security is an issue as access rights are not administered by a central server

Question 16

Bandwidth

Answer 16

The average number of bits of data that can be transmitted from a source to a destination over the network in one second

Megabits per second
Gigabits per second

Question 17

Identifiers

Answer 17

1. Port number

2. Service set identifier (SSID)

Question 18

Port number

Answer 18

Number that is used together with an IP address to uniquely identify a program that is running on a network

Question 19

Service set identifier (SSID)

Answer 19

A 32-byte string that identifies a wireless access point (WAP) and all devices connected to it

Question 20

Network interface controller (NIC)

Answer 20

Provides the hardware interface to enable the transfer of data between a device and a network

Physically / Wirelessly

Question 21

Network hub

Answer 21

Device that transmits received packets to all connected devices

Question 22

Packet

Answer 22

A unit of broken-up data containing a header with information about the source and destination addresses that are needed for transmission

Question 23

Network switch

Answer 23

Device that constructs a single network by connecting multiple similar networks together

Question 24

Router

Answer 24

Device that forwards packets between separate networks

Question 25

Modem

Answer 25

Responsible for modulation and demodulation

Demodulation
Conversion of transmitted signals into digital data
Modulation
Conversion of digital data into a form suitable for transmission

Question 26

Network topologies

Answer 26

1. Bus
2. Ring
3. Star

Question 27

Bus topology

Answer 27

During communication, a sender will transmit data along the bus and all the devices connected to the bus can detect that data is being transmitted. However, only the intended recipient will accept and process the data

Advantage
Can continue to operate even when one of the computers breaks down
Disadvantage
The size of the network is limited by the capacity and length of the bus

Question 28

Ring topology

Answer 28

In a ring topology, each computer is connected to two other computers in a ring formation. All the data is passed around in the same direction. If a failure occurs in the cable or if a computer breaks down, the entire network will fail to function

Advantage
Can operate over large distances and handle more data than a bus topology
Disadvantage
If the cable or a computer in the network fails , the entire network may fail as the data cannot be passed on

Question 29

Star topology

Answer 29

In a star topology, network hardware such as a hub is at the centre of the network with connections to all the other computers. The computers will send data to the central network hardware and the hardware forwards the data to the intended destination

Advantage
The load on each section of cabling is reduced as each computer uses a separate network from the rest
Disadvantage
If the central network hardware fails, the entire network fails

Question 30

Error checking methods in data transmission

Answer 30

1. Parity check

2. Checksum

Question 31

Parity check

Answer 31

Error-checking technique which uses a parity bit to detect data

Parity bit —> prepend append

Question 32

Checksum

Answer 32

Calculated value that is used to determine the integrity of transmitted data