Exams on a data communication and networking course at this level usually follow a familiar shape. A common layout is five to seven questions, of which you answer four or five in 2½ to 3 hours; some papers make one question compulsory and let you choose the rest ("answer question one and any three others"). Each question is usually worth 15–20 marks, split into two to four parts of roughly 4–8 marks, so you have about 35–45 minutes per question — enough for a careful diagram and a clean table if you plan before you write.

The questions come from a small, friendly territory. Expect definitions with a diagram (data communication and its five components, the network criteria), the OSI model — very often a whole question explaining every layer, sometimes on both the sending and receiving machine — and "differentiate" pairs such as OSI vs TCP/IP, logical vs MAC address, or access control vs error control. Signals bring transmission impairments and the occasional calculation (decibels, bandwidth, Shannon, delay); synchronisation brings line coding and "why must the physical layer keep bits in step?"; error detection brings parity, checksums, CRC and burst errors, often with numbers to work. Application layer protocols, devices per layer and the aspects of security make tidy short parts.

A calm strategy: read every question before choosing, and pick the ones where you can draw a diagram or build a table — examiners reward legible, labelled diagrams. For every "differentiate", define both terms first, then give a table with at least as many rows as the marks suggest. For every "explain", give a definition, then the how, then an example. For calculations, show every step (each XOR line, each wrapped carry) and check your answer at the receiver's end. Calm, structured, labelled — that is what full marks look like here.