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SingaporeComputer Science

Networks and the Internet

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does a domain name become an IP address, and what protocols carry web traffic?

Explain how DNS resolves domain names to IP addresses, and describe the HTTP/HTTPS request-response model and the client-server architecture
A focused answer to the H2 Computing outcome on DNS and the web. Resolving domain names to IP addresses through DNS, the HTTP and HTTPS request-response cycle, status codes, and the client-server model.
8 min answer →

How are devices addressed on the internet, and how does a subnet mask split a network from a host?

Explain IPv4 addressing, the role of the subnet mask in separating network and host parts, and the motivation for IPv6
A focused answer to the H2 Computing outcome on IP addressing. The structure of an IPv4 address, how a subnet mask divides network and host bits, calculating hosts per subnet, and why IPv6 was introduced.
8 min answer →

How is data kept confidential and authentic over a network, and how do symmetric and public-key encryption work?

Explain symmetric and public-key (asymmetric) encryption, digital signatures and common network threats and defences
A focused answer to the H2 Computing outcome on network security. Symmetric and public-key encryption, the key-distribution problem, digital signatures for authenticity, hashing, and common threats and defences.
9 min answer →

How does data cross the internet as packets, and how do routers decide where to send them?

Explain packet switching, the structure of a packet, how routers forward packets, and contrast it with circuit switching
A focused answer to the H2 Computing outcome on packet switching. How data is split into packets, packet structure with headers, how routers forward packets hop by hop, and the contrast with circuit switching.
8 min answer →

How is network communication organised into layers, and what does each layer of the TCP/IP model do?

Describe the layered TCP/IP model, the role of each layer, and how encapsulation passes data between layers
A focused answer to the H2 Computing outcome on the TCP/IP model. The application, transport, internet and link layers, the role of each, encapsulation of data into segments and packets and frames, and why layering matters.
8 min answer →