Cambridge AS Computer Science - Networks & the Internet (Review Flashcards)

A comprehensive set of Q&A flashcards covering networks, topologies, cloud computing, transmission media, Internet, IP addressing, DNS, and related hardware.

What is a Local Area Network (LAN)?

A network covering a small geographical area (under 1 mile) owned by a single organization, using media such as UTP, fibre optic, or Wi‑Fi to share resources and data.

What are common advantages of LANs?

Shared resources (printers, files), centralized management, easier backups, cost-effective software licences, and easier communication.

What is a Wide Area Network (WAN)?

A network that covers a large geographical area, made up of multiple LANs connected by routers, often using telecom media; hardware is not all owned by the organization.

What is a Wireless Local Area Network (WLAN)?

A LAN where devices connect wirelessly via Wi‑Fi using Wireless Access Points (WAPs) or hotspots.

What is a thin-client?

A client that relies on a permanent connection to a server to function; processing is done on the server (e.g., Google Docs, remote desktop).

What is a thick-client?

A client that can run independently with its own processing power and may connect to a network for updates or data sharing; can operate offline.

Difference between client-server and peer-to-peer networks?

Client-server uses central servers to provide services and is scalable but has a single point of failure; peer-to-peer has no central server, peers share resources, is cheaper and simpler but not suited to large networks.

What is a bus topology?

All devices are connected by a single bus cable with end terminators; data is shared along the cable and may collide.

What is a star topology?

All devices connect to a central switch; traffic is directed to the correct device; switches are smarter than hubs.

What is a mesh topology?

Every computer can connect to every other, providing multiple paths for data (full mesh is common in IoT); highly fault-tolerant but costly.

What is a hybrid topology?

A mix of two or more different topologies (e.g., bus, star, mesh) to combine their strengths and weaknesses.

What is cloud computing?

Accessing software, services, or files hosted on remote servers via the internet.

What is cloud storage?

Long-term storage of data on remote servers in data centers, accessible over the internet (e.g., Google Drive, Dropbox, OneDrive).

What is cloud software?

Software hosted and managed remotely; users access it online with maintenance, upgrades, and security handled by the provider (often via subscription).

Public cloud vs private cloud (ownership and access)

Public cloud: services provided by a third-party over the internet; shared and cheaper. Private cloud: owned by the company, with access restricted to the organization and greater control.

What are transmission media and the main wired options?

Transmission media are cables used to transmit data; main wired options are twisted pair, coaxial cable, and fibre optic.

What are the advantages of wired networks?

Fast data transfer, better security, reliability, though less portable and more cabling cost.

What is Ethernet?

A wired LAN protocol that transmits data in frames and uses CSMA/CD to detect/avoid collisions.

What is CSMA/CD?

Carrier Sense Multiple Access with Collision Detection; devices listen before transmitting, collisions are detected, jam signals are sent, and devices back off randomly.

What is a network hub?

A basic, non intelligent device that broadcasts incoming data to all ports, which can cause inefficiency and security issues.

What is a network switch?

A device that forwards data only to the destination port using MAC address tables, improving efficiency.

What is a NIC (Network Interface Card)?

Hardware that enables a device to connect to a network; has a unique MAC address.

What is a WNIC (Wireless NIC)?

A NIC built into devices that connects wirelessly via radio waves to a WAP or router.

What is a Wireless Access Point (WAP)?

A device that allows wireless devices to connect to a wired network, extending the network’s range.

What is a bridge in networking?

A device that connects two LAN segments at Layer 2, filtering traffic by MAC addresses to reduce unnecessary traffic.

What is a repeater?

A device that boosts or regenerates signals to extend the range of a wired or wireless network.

What is a router?

A device that routes data between networks, determines the best path for packets, may include firewall and switch features, and connects LANs to WANs.

What is an IP address?

A unique identifier for devices on an IP network; can be IPv4 or IPv6 and may be static or dynamic.

What is IPv4?

An addressing scheme with four decimal octets (0-255), 32 bits total, usually written as four numbers separated by dots.

What is IPv6?

An addressing scheme with eight groups of four hexadecimal digits, 128 bits total, separated by colons.

What is subnetting?

Dividing a larger network into smaller subnets to reduce broadcast domains, improve performance, security, and manageability.

Public vs private IP addresses?

Public IPs are globally unique and routable on the internet; private IPs are used inside a LAN and are not routable on the public internet.

Static vs dynamic IP addresses?

Static IPs are fixed addresses; dynamic IPs are assigned by DHCP and can change.

What is a URL?

A Uniform Resource Locator, the web address used to locate a resource; typically includes protocol, domain name, and path.

What is DNS?

Domain Name System; translates domain names to IP addresses, enabling browsers to locate servers; propagation updates can take time.

What happens when you type a URL in a browser (DNS process)?

The browser checks its cache; if unknown, it queries a DNS server to find the IP; if not found, it queries higher-level DNS servers (root, TLD, authoritative) until the IP is returned.

What is the difference between the Internet and the World Wide Web?

The Internet is the global network of networks using protocols like TCP/IP; the Web is a collection of websites accessed via the Internet using HTTP/HTTPS.

What is a Bit streaming and its two types?

Bit streaming is the continuous flow of data for real-time services; types are real-time (live) and on-demand (buffered).

What is HTTP (Hypertext Transfer Protocol)?

The foundational protocol for the World Wide Web, used for transmitting web pages and other content from web servers to web browsers.

What is HTTPS (Hypertext Transfer Protocol Secure)?

A secure version of HTTP that uses SSL/TLS encryption to protect data transmitted between a web browser and a server.

What is FTP (File Transfer Protocol)?

A standard network protocol used for transferring computer files from a server to a client on a computer network.

What is a Firewall?

A network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules; it can be hardware or software-based.

What is a VPN (Virtual Private Network)?

A technology that creates a secure, encrypted connection over a less secure network, such as the internet, to provide privacy and anonymity.