fundamentals of computer networks

Question 1

define what a computer network is


Answer 1

a collection of computers connected together for the purpose of communication

Question 2

advantages of computer networks

Answer 2

• easier to share files: users can access same files and work on them at the same time
• can share the same hardware (e.g. printers) on multiple devices
• can install and update all computers at once
• can communicate across a network easily and cheaply
  user accounts are stored centrally: users can log in from any device on the network

Question 3

disadvantages of computer networks

Answer 3

expensive to set up: need lots of extra hardware
vulnerable to hacking: malware can be easily spread
dependent on multiple servers: if those servers go down it can be disruptive
difficult to manage: larger networks need a specialist to maintain them

Question 4

describe Personal Area Network (PAN)

Answer 4

a network that covers a small range of a few metres, and connects personal devices using Bluetooth

Question 5

describe Local Area Network (LAN)

Answer 5

a network that is geographically confined to one building or site usually managed by a single person or organisation

Question 6

describe Wide Area Network (WAN)

Answer 6

a network that covers a wide geographical area and connects LANs that is managed by telecommunications companies

Question 7

advantages of wireless networks

Answer 7

convenient: devices automatically connect to the network and can move around while connected
cheaper and better for environment: no wires are needed
easier to add more users: no extra wires needed

Question 8

disadvantages of wireless networks

Answer 8

less secure: access points are visible to all devices
reduced signal strength: distance from WAP, interference from other wireless networks, physical obstructions affect signal
lower bandwidth

Question 9

name network hardwares

Answer 9

Network Interface Card (NIC): inside device that allows it to connect to networks
Switch: used to connect devices on a LAN
Router: transmits data between different networks and to connect to the internet
MAC address: unique identifier assigned by manufacturer

Question 10

choice of cables depends on…

Answer 10

cost
bandwidth (amount of data sent across a network in a given time)
distance of data transmission

Question 11

describe fibre optic cables

Answer 11

transmit data as light
high performance
expensive
transmit over large distances at high bandwidth without loss of signal quality

Question 12

describe ethernet cables

Answer 12

contain pair of copper wires twisted together to reduce internal interference
cheaper
average bandwidth

Question 13

describe coaxial wires

Answer 13

a single copper wire surrounded by a plastic layer and metallic mesh for insulation and shielding from outside interference
very cheap
low bandwidth

Question 14

describe star topology 


Answer 14

all computers have their own cable connecting them to the switch, which routes information to the correct computer, and usually controlled by a server.

Question 15

disadvantages of star topology

Answer 15

costly to install: lots of extra hardware
if server or switch fails then the whole network goes down

Question 16

advantages of star topology

Answer 16

if one cable fails, the other workstations are not affected
maintains performance: even if many devices are connected
good security: data can only be received by the intended node

Question 17

advantages of bus topology

Answer 17

inexpensive and easy to install: less cabling
no reliance on a central node

Question 18

describe bus topology

Answer 18

all computers connected to a single backbone cable
(only one computer can successfully transmit at one time. if a network is too busy there can be collisions and computers have to retransmit. as no. of collisions increase, the network slows down)

Question 19

disadvantages of bus topology

Answer 19

if main cable fails the whole network goes down
as amount of traffic increases, the performance slows down
low security: every node can see all transmissions

Question 20

define the Ethernet

Answer 20

a family of related protocols

Question 21

explain the purpose and use of Wi-Fi

Answer 21

deals with the transmission of data on wireless LANs

Question 22

Explain the purpose and use of the Ethernet

Answer 22

deals with how data is sent and received and how hardware and data collisions are managed for wired connections

Question 23

explain the purpose and use of TCP (transmission control protocol)

Answer 23

splits data into numbered packets and reassembled them at destination
communicates with receiving devices: if any packets that are missing/faulty can be resent

Question 24

explain the purpose and use of UDP (user datagram protocol)

Answer 24

splits data into packets without numbers: they are read by the receiving device in order and doesn’t check if everything has been received

Question 25

explain the purpose and use of IP (internet protocol)

Answer 25

routes and addresses data packets to device location via routers and manages network traffic

Question 26

explain the purpose and use of HTTP (hypertext transfer protocol)


Answer 26

used for accessing and receiving web pages as HTML files on the internet

Question 27

explain the purpose and use of HTTPS (hypertext transfer protocol secure)


Answer 27

used for accessing and receiving web pages as HTML files on the internet, BUT encrypts the information

Question 28

explain the purpose and use of FTP (file transfer protocol)


Answer 28

used to transfer files between computers and the internet

Question 29

mail servers pass on and store emails until collected.

Answer 29

-

Question 30

explain the purpose and use of SMTP (simple mail transfer protocol)

Answer 30

a protocol used for sending and receiving emails between servers

Question 31

explain the purpose and use of IMAP (internet messaging access protocol)

Answer 31

a protocol that stores and receives emails from a mail server and enables the receiver to store them locally on their device

Question 32

why do we need/what is the importance of network security?

Answer 32

to keep unauthorised people from accessing data to ensure authorised people can access data protect against damage protect against cyber attacks

Question 33

describe authentication

Answer 33

the process of verifying the identity of a user to prevent unauthorised people from accessing data on a network

Question 34

what are the factors of authentication?

Answer 34

something you are: username something you know: password something you have: biometrics

Question 35

describe encryption


Answer 35

the process disguising a message so it can only be understood by the recipient

Question 36

define encryption

Answer 36

the process of converting plaintext into ciphertext

Question 37

define decryption

Answer 37

the process of converting ciphertext into plaintext

Question 38

describe a firewall


Answer 38

a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules

Question 39

describe MAC address filtering

Answer 39

allows devices to access or be blocked from accessing a network based on their MAC address embedded within the device's network adapter

Question 40

examples of authentication

Answer 40

fingerprint or facial recognision entering a PIN

Question 41

example of encryption

Answer 41

the Caesar cipher

Question 42

examples of MAC address filtering

Answer 42

being whitelisted being blacklisted

Question 43

describe the main function of the application layer of the TCP/IP model

Answer 43

where the network applications (e.g. web browsers or email programs) operate

Question 44

describe the main function of the transport layer of the TCP/IP model


Answer 44

sets up the communication between two devices and establishes settings (e.g. size of packet) splits data into packets and adds packet information

Question 45

describe the main function of the internet layer of the TCP/IP model

Answer 45

address and packages data for transmission and routes the packets across the network adds IP address and destinations IP address

Question 46

describe the main function of the link layer of the TCP/IP model

Answer 46

passes data over the physical network contains the NIC (network interface card) and OS device drivers adds MAC addresses of both sender and recipient

Question 47

name protocols used in the application layer

Answer 47

HTTP, HTTPS, FTP, IMAP, SMTP

Question 48

name protocols used in the transport layer


Answer 48

TCP, UTP

Question 49

name protocols used in the internet layer

Answer 49

IP

Question 50

name protocols used in link layer

Answer 50

Wi-Fi, Ethernet