I T 1 2 4 Communications Technologies, Networks & the Internet Flashcards

A comprehensive set of vocabulary flashcards covering computer network fundamentals, topologies, internet services, security threats, and protective measures based on I T 1 2 4 lecture notes.

Computer Network

A group of connected devices that share data and resources, consisting of nodes (like computers), links (like cables), and protocols (rules).

Data Communication

The electronic transmission of data between two or more devices over a communications channel including collection, processing, and distribution via a medium.

Sender

The device that originates and transmits data, such as a computer, smartphone, or sensor.

Encoder / Transmitter

A component that converts data into a form suitable for transmission, such as electrical or optical pulses.

Transmission Medium

The physical or wireless path a signal travels, such as copper cable, fibre optic, radio waves, or satellite.

Decoder / Receiver

A component that converts a transmitted signal back into usable data.

Destination / Recipient

The device that receives the final data, such as a server, PC, printer, or cloud service.

Local Area Network (LAN)

A network connecting devices within a limited geographic area (room to few kilometres) with high speeds typically from $100\,Mbps$ to $10\,Gbps$.

Metropolitan Area Network (MAN)

A network covering a city or large campus up to $\sim 50\,km$, typically connecting multiple LANs via fibre optic rings or WiMAX.

Wide Area Network (WAN)

A network covering countries or the globe using public and private infrastructure, such as the Internet or GCNet.

Network Topology

The physical and logical arrangement of devices in a network.

Bus Topology

A structure where all devices share a single backbone cable terminated at both ends; simple and cheap but a single break stops the entire network.

Star Topology

A structure where each device has a dedicated cable to a central switch; it is the modern LAN standard and prevents single cable failures from affecting other devices.

Ring Topology

A structure where each device connects to two neighbours forming a closed loop, often using a token to control data passage.

Mesh Topology

A structure where every device connects to every other providing maximum redundancy and alternative paths via $\frac{n(n-1)}{2}$ links.

Tree (Hierarchical) Topology

A hierarchy of stars connecting core, distribution, and access layers; common in large campus networks like GCTU.

Hybrid Topology

A network that combines two or more different topologies, such as star LANs joined by a fibre ring backbone.

Internet

A worldwide system of interconnected computer networks using the TCP/IP protocol suite to link billions of devices.

World Wide Web (WWW)

A system of interlinked web pages accessed via browsers using HTTP/HTTPS; it runs on top of the Internet.

DNS (Domain Name System)

The 'phone book' of the internet that translates human-readable domain names into IP addresses.

Internet of Things (IoT)

A network of everyday objects embedded with software and connectivity to collect, exchange, and act on data with little human involvement.

Network Security

The policies, technologies, and practices designed to protect the integrity, confidentiality, and availability of data and systems.

Malware

Malicious software types including viruses, worms, trojans, ransomware, and spyware that corrupt or steal data.

Phishing

Tricks used to reveal passwords or PINs by impersonating trusted organisations via email or SMS (smishing).

Denial of Service (DoS/DDoS)

Attacks that overwhelm a server or network with traffic until it becomes unavailable to legitimate users.

Privacy

A citizen's right to control what personal data is collected, how it is used, and who it is shared with.

Firewall

A primary perimeter defence that monitors and filters incoming and outgoing network traffic based on security rules.

Multi-Factor Authentication (MFA)

A security measure requiring two or more verification factors, such as a password, OTP, and a biometric characteristic.

Virtual Private Network (VPN)

Technology that creates an encrypted tunnel over the internet to allow secure remote access to organisational systems.

Biometric Authentication

Identity verification using unique physical or behavioural traits like fingerprints, face, iris, or voice.

PIN (Personal Identification Number)

A short secret numeric code memorised by a user to prove identity, commonly used for ATM and mobile money (MoMo) wallets.