Networks

Question 1

LAN (local area network)

Answer 1

A network covering a small geographic area, like a home, school, or office, where devices are connected directly.
🧠 Example: School computers connected to the same server.

Question 2

Virtual local area network (VLAN)

Answer 2

A logical subdivision of a LAN that groups devices into separate virtual networks even if they’re on the same physical infrastructure.
🧠 Example: Separating teacher and student devices on the same school network using VLANs.

Question 3

Wide area network (WAN)

Answer 3

A network that covers a large geographic area and connects multiple LANs using routers and public lines.
🧠 Example: A multinational company’s offices connected across continents.

Question 4

Storage area network (SAN)

Answer 4

A specialized high-speed network that provides access to centralized data storage.
🧠 Example: A data center where servers access shared storage through a SAN.

Question 5

Wireless local area network (WLAN)

Answer 5

A LAN that allows devices to connect wirelessly via radio signals, typically Wi-Fi.
🧠 Example: Home Wi-Fi connecting your laptop, phone, and smart TV.

Question 6

Internet

Answer 6

The internet is a global network that connects millions of computers and other devices so they can share data and communicate with each other.

Question 7

Extranet

Answer 7

A private network that allows authorized external users to access parts of a company’s internal system.
🧠 Example: A supplier accessing a retail company’s inventory system to manage stock levels.

Question 8

Virtual private network (VPN)

Answer 8

A secure, encrypted connection over a public network that provides privacy and safe data transfer.
🧠 Example: An employee working from home using a VPN to access their company’s internal system.

Question 9

Personal area network (PAN)

Answer 9

A very small network used for personal devices within close range.
🧠 Example: A Bluetooth connection between a smartphone and wireless earbuds.

Question 10

Peer-to-peer(P2P)

Answer 10

A network model where all devices (peers) are equal and share resources without a central server.
🧠 Example: Torrenting files using software like BitTorrent.

Question 11

Standards

Answer 11

Agreed rules that ensure devices and systems can communicate and operate together on a network.

Question 12

OSI seven layer model

Answer 12

A conceptual model that divides the communication process into seven layers, from hardware to user-facing applications.
🧠 Example: Sending a message over WhatsApp involves all seven OSI layers from physical transmission to app-level display.

Question 13

Evaluate the use of a VPN

Answer 13

A VPN (Virtual Private Network) allows users to create a secure, encrypted connection over a public network such as the internet. It is commonly used to protect privacy, access restricted resources, and work remotely.

Advantages: Data security and privacy, remote access, bypassing restrictions
Disadvantages: Reduced speed, reliability and trust, compatibility issues

Question 14

Protocol

Answer 14

A set of rules that defines how data is formatted, transmitted, and received over a network.
Analogy: With driving, there is a driving protocol, such that “right of way” prevents deadlocks and congestions
🧠 Example: HTTP for web browsing, TCP/IP for general internet communication.

Question 15

Data packet

Answer 15

A small unit of data sent across a network, which includes payload (the actual data) plus control information like destination address and error checking.
🧠 Example: A file sent over the internet is broken into multiple packets.

Question 16

Data integrity

Answer 16

Ensures that data is not altered or corrupted during transmission — the data received is exactly the same as what was sent.
🧠 Example: Using checksums or hashing to verify a file wasn’t changed during download.

Question 17

Flow control

Answer 17

A technique that manages the rate of data transmission between sender and receiver to prevent overwhelming the receiver.

Question 18

Deadlock

Answer 18

A state in a network where two or more processes are waiting for each other to release resources, causing all to stop.
🧠 Example: Two devices waiting to send data, but each is waiting for the other to respond first — nothing moves.

Question 19

Congestion

Answer 19

Occurs when too much data is sent through a network at once, leading to packet loss, delays, or decreased performance.
🧠 Example: A video call lagging because many users are streaming or downloading large files at the same time.

Question 20

Error checking

Answer 20

Error checking is a process where a small value (like a parity bit, checksum, or hash function) is added to data to detect changes during transmission or storage. The receiver recalculates the value and compares it; if it matches, the data is likely correct.

Question 21

Explain why the speed of data transmissions across a network can vary

Answer 21

Network congestion: When too many devices are using the network at once, it can cause delays or packet loss.
Distance: Longer physical distances between sender and receiver can increase latency, especially over WANs.

Question 22

Compression of data

Answer 22

The process of reducing the size of data files so that they take up less space and can be transmitted more quickly.

Question 23

Explain why compression of data is often necessary when transmitting across a network

Answer 23

Speeds up transmission — less data = faster delivery, especially on slower or congested networks
Lowers cost — especially for mobile data or cloud storage providers that charge by usage

Question 24

Bandwidth

Answer 24

The maximum amount of data that can be transmitted over a network in a given amount of time, usually measured in bits per second (bps).

Question 25

Transmission media

Answer 25

Transmission media are the physical or wireless pathways used to transmit data between devices in a network.

Question 26

Transmission media types

Answer 26

metal conductor (inexpensive but slow), fibre optic (high speed but expensive), wireless/radio waves (convenient but security risks)

Question 27

Characterstics of different transmission media

Answer 27

speed, reliability, cost and security

Question 28

Explain how data is transmitted by packet switching

Answer 28

Packet switching is a method of transmitting data over a network by breaking it into small packets, which are sent independently and can take different routes to reach the destination, where they are reassembled into the original message.

Question 29

Wirelss network

Answer 29

A wireless network allows devices to connect and communicate without physical cables, using radio waves (such as Wi-Fi or Bluetooth).

Question 30

Advantages of wireless networks

Answer 30

Mobility, easy installation, supports many devices, convenient

Question 31

Disadvantages of wireless networks

Answer 31

Slow speed, signal interference (from walls, etc), security risks, limited range

Question 32

Describe hardware components of wireless networks

Answer 32

Wireless router, Wireless network interface card (NIC), Access points (APs), Modem

Question 33

Describe the software components of wireless networks

Answer 33

Protocols, Network operating system (NOS), Security software

Question 34

Describe the characteristics of wireless networks

Answer 34

WiFi, Worldwide interoperability for Microwave access, 3G mobile, future networks, connectivity between different locations

Question 35

Encryption

Answer 35

Converts data into unreadable form to protect it during transmission. ✅ Advantages: Secures data from unauthorized access during transmission Protects sensitive information even if intercepted ❌ Disadvantages: Requires processing power, which may slow performance If encryption keys are lost or stolen, data can be exposed

Question 36

UserID (method of network security)

Answer 36

Requires a user to log in with a username and password. ✅ Advantages: Helps control access to network resources Allows for individual tracking and auditing of user activity ❌ Disadvantages: Can be guessed or stolen if passwords are weak or reused Does not protect against users inside the network who misuse access

Question 37

Trusted MAC (media access control) address (method of network security)

Answer 37

Allows only devices with approved MAC addresses to connect to the network. ✅ Advantages: Blocks unauthorized devices from connecting Works automatically — no login required by the user ❌ Disadvantages: MAC addresses can be spoofed (faked by attackers) Requires manual management — not practical for large networks

Question 38

What are the layers in the OSI model? (Name at least 2)

Answer 38

1. Application 2. Presentation 3. Session 4. Transport 5. Network 6. Data Link 7. Physical

Question 39

Physical Layer (1)

Answer 39

The layer that transmits raw binary data over physical mediums like cables or radio waves.

Question 40

Data Link Layer (2)

Answer 40

The layer that ensures error-free data transfer between two directly connected devices using MAC addresses.

Question 41

Network Layer (3)

Answer 41

The layer that routes data between devices on different networks using IP addresses.

Question 42

Transport Layer (4)

Answer 42

The layer that provides reliable data transfer, error correction, and flow control between host systems (e.g., TCP/UDP).

Question 43

Session Layer (5)

Answer 43

The layer that manages, opens, and closes sessions between applications on different devices.

Question 44

Presentation Layer (6)

Answer 44

The layer that translates, encrypts, and compresses data to ensure it's readable by the receiving system.

Question 45

Application Layer (7)

Answer 45

The layer that provides network services directly to user applications (like email, file transfer, or web browsing).

Question 46

Protocol vs standards

Answer 46

🔁 Protocol = specific rules for communication 📏 Standard = official guide that defines those rules (and more) so everyone can follow the same system

Question 47

Circuit switching

Answer 47

Circuit switching is a method of communication where a dedicated path is established between two devices for the entire duration of a session, ensuring data follows the same route in order. It's like a traditional phone call — the line stays open the whole time, even during silence, providing consistent quality but using resources inefficiently.

Question 48

HTTPS - Hypertext Transfer Protocol Secure

Answer 48

This is the secure version of the protocol used to load websites. It makes sure the information you send or receive (like passwords or credit card numbers) is encrypted, so no one can read it if they intercept it. Used in almost all modern websites (you’ll see the 🔒 lock icon in your browser).

Question 49

SFTP - Secure File Transfer Protocol

Answer 49

A protocol that lets you safely send and receive files over the internet. It uses something called SSH (Secure Shell) to encrypt everything, so your files can’t be read or stolen while being transferred between computers.

Question 50

TCP/IP - Transfer Control Protocol / Internet Protocol

Answer 50

This is actually a set of rules that runs the internet: IP (Internet Protocol) decides where data should go — like an address on an envelope. TCP (Transmission Control Protocol) makes sure all the data arrives, in the right order, without anything missing. Together, they’re like the postal system of the internet — delivering data to the right place safely and correctly.

Question 51

HTTP - Hypertext Transfer Protocol

Answer 51

This is the basic rule that lets you load websites. It tells your browser how to ask a server for pages, images, videos, etc. Unlike HTTPS, HTTP does not protect your data — it’s like sending a postcard that anyone can read.

Question 52

SNMP - Simple Network Management Protocol

Answer 52

Used by IT people to monitor and manage devices on a network (like printers, switches, routers). It can check if devices are working, report problems, or update settings — like a remote control panel for network stuff.

Question 53

ICMP - Internet Control Message Protocol

Answer 53

A helper protocol used by computers and routers to send error messages or updates about what’s happening on the network. For example, when you use the “ping” command to see if a website is reachable, ICMP is what sends the reply back.

Question 54

Code Obfuscation (method of network security)

Answer 54

Code obfuscation is the process of making source code intentionally difficult to read or understand without changing its function. Purpose: Protects intellectual property Prevents reverse engineering Secures sensitive logic ✅ Advantages: Increases code security Hides implementation details ❌ Disadvantages: Hard to debug or maintain May reduce performance Doesn't fully stop decompilation

Question 55

Blacklisting (method of network security)

Answer 55

Blacklisting is a security method that blocks specific entities, such as IP addresses, users, websites, or applications that are known to be harmful or untrusted. Purpose: Prevents access to known threats Used in firewalls, email filters, web browsers, etc. ✅ Advantages: Easy to implement Efficient against known malicious sources ❌ Disadvantages: Cannot stop unknown/new threats Needs constant updating Can result in false positives

Question 56

Whitelisting (method of network security)

Answer 56

Whitelisting is a security approach that only allows approved entities (like IP addresses, users, apps, or websites) to access a system or network. Everything else is blocked by default. Purpose: Ensures that only trusted sources are allowed Common in application control, email filtering, and network access control ✅ Advantages: Strong protection against unknown threats Reduces attack surface significantly ❌ Disadvantages: Requires careful setup and maintenance Can block legitimate access if not updated Less flexible than blacklisting

Question 57

Firewalls (method of network security)

Answer 57

A firewall is a security system (hardware, software, or both) that monitors and controls network traffic based on predefined rules to block unauthorized access. Purpose: Acts as a barrier between trusted and untrusted networks Filters incoming and outgoing data packets Can allow, block, or limit traffic based on IP, port, or protocol ✅ Advantages: Prevents unauthorized access Protects against common network threats Can enforce security policies ❌ Disadvantages: Doesn’t protect against threats inside the network Can be bypassed if misconfigured May slow down traffic if overused

Question 58

Asymmetric Encryption (encryption types)

Answer 58

Asymmetric encryption uses two keys: a public key to encrypt data and a private key to decrypt it. The keys are mathematically linked, but one cannot be used to derive the other. How it works: The sender encrypts data using the recipient’s public key Only the recipient’s private key can decrypt it The private key is kept secret; the public key is shared openly ✅ Advantages: No need to share a secret key Enables secure communication over insecure channels Used in digital signatures and SSL/TLS ❌ Disadvantages: Slower than symmetric encryption More computationally intensive

Question 59

Tunnelling

Answer 59

Tunnelling is a method used to send data securely across a network by encapsulating it inside another data packet. It allows private network communications to be sent over public networks like the internet, often used in VPNs to protect data through encryption.

Question 60

Router

Answer 60

A router is a networking device that forwards data packets between different computer networks. It determines the best path for the data to travel from the source to the destination using routing tables and protocols.

Question 61

DNS server

Answer 61

A DNS (Domain Name System) server translates human-readable domain names (like www.example.com) into IP addresses that computers use to identify each other on the network. It acts as a directory for internet resources.

Question 62

Email server

Answer 62

An email server is a computer system that sends, receives, stores, and manages emails. It uses protocols such as SMTP for sending and IMAP or POP3 for retrieving messages.