Data Communications and Networks
What you must know
A network links devices to share resources and communicate. Learn LAN vs WAN, client–server vs peer-to-peer, topologies (star, bus, ring, mesh), transmission media (copper cable, fibre optic, wireless), protocols (TCP/IP, HTTP, FTP, SMTP), IP and MAC addresses, and hardware such as routers, switches, hubs and NICs. Understand bandwidth, latency, packet switching and the difference between the internet and the World Wide Web.
Traps candidates fall into
- Saying the internet and the web are the same - the web is a service on the internet.
- Confusing a hub (broadcasts to all ports) with a switch (sends to the intended device).
- Mixing IP (logical, can change) with MAC (physical, fixed to the NIC).
- Claiming fibre optic is best everywhere - it is fast but costly and fragile.
- Forgetting that a star topology fails gracefully (one cable down does not stop the network) but depends on the central switch.
Rule of thumb
Choose a topology by weighing cost, fault tolerance and ease of expansion; a star is the usual classroom answer for reliability and easy fault-finding.
Worked example
A company with two offices in different cities needs a WAN. Justify: a WAN spans large distances, uses leased lines or the internet, and connects LANs at each site. Within each office use a star LAN for reliability.