Led by Edsger Dijkstra Simulacrum
About this course
The third module of OCR GCSE Computer Science (J277/01, section 1.3), taught by the man whose shortest-path algorithm runs inside the routers that hold the internet together. Dijkstra is a fitting host: he thought about how messages find their way across a connected graph of nodes — which is exactly what a network is — and insisted that a system you cannot reason about clearly is one you cannot trust.
The module covers LANs and WANs and what affects their performance; client-server and peer-to-peer; the hardware that builds a network; the internet as a worldwide network with DNS, hosting and the cloud; star and mesh topologies; wired and wireless connection; encryption, IP and MAC addressing, and standards; the common protocols (TCP/IP, HTTP, HTTPS, FTP, POP, IMAP, SMTP); and the concept of layers.
Dijkstra teaches networking as a set of agreements — protocols — that let machines built by strangers cooperate.
This is a written-exam course. The module ends with the student able to describe network types, hardware and topologies, explain addressing and the main protocols, and reason about layered communication.
Led by Edsger Dijkstra Simulacrum
The question
A network is just computers that have agreed on how to pass messages — and most of what looks complicated is really a stack of those agreements, called protocols, layered on top of each other. The student starts with the shapes networks take: LANs and WANs and what affects their performance, the client-server and peer-to-peer models, the hardware that builds a LAN (routers, switches, NICs, access points), the internet as a network of networks with DNS, hosting and the cloud, and the star and mesh topologies. Then the agreements themselves: wired versus wireless connection and how to choose, encryption, IP and MAC addressing and their formats, the principle of a standard, the common protocols (TCP/IP, HTTP, HTTPS, FTP, POP, IMAP, SMTP) and what each is for, and why communication is organised into layers.
Outcome
The student can describe LANs and WANs and what affects performance, distinguish client-server from peer-to-peer, name network hardware and its tasks, explain DNS and the cloud, compare star and mesh topologies, compare wired and wireless for a scenario, explain encryption and IP and MAC addressing, state what each common protocol is for, and explain the concept of layers.
Sub-units