OCR GCSE Networks: LAN vs WAN, Topologies & Hardware

Networking questions in OCR GCSE J277 frequently combine LAN/WAN characteristics, topology comparisons, and hardware responsibilities in one scenario. This guide will sharpen your definitions, help you evaluate design choices, and prepare you for data-driven questions. Keep revisiting related articles such as the network security revision piece and our overview of ethical and legal impacts, because security and policy decisions are often bundled into networking marks.

LAN vs WAN in OCR Exam Language

Begin every comparison with scope: Local Area Networks cover a small geographic area like a school building, while Wide Area Networks span cities or countries and rely on third-party infrastructure. The specification expects you to discuss technologies such as leased lines, fibre, copper, and cellular. When summarising benefits, mention the easier maintenance and higher security control of LANs contrasted with the cost and reliability trade-offs of WANs. Remember to reference bandwidth calculations; examiners like giving file size and transfer rate data to test your ability to convert bits to bytes and compute download times.

Key Exam Points

Define the purpose of each network hardware component: routers direct traffic between networks, switches manage frames within a LAN, wireless access points provide radio connectivity, and NICs enable devices to join the network.
Explain star topologies as having dedicated connections to a central switch, providing resilience but depending on the switch; compare with mesh, bus, and ring structures.
Describe how performance factors – number of users, bandwidth, latency, error rates – affect throughput.
Demonstrate understanding of the packet switching process: segmentation, addressing, routing decisions, and reassembly.
Show knowledge of Ethernet standards, including frame structure, CSMA/CD, and the difference between wired and wireless transmission media.
Discuss client-server versus peer-to-peer networks, focusing on control, data security, and typical use cases.
Include cable types and their properties: twisted pair reduces interference, fibre optic offers high bandwidth and long distances, coaxial is legacy but still examinable.
Integrate IP addressing modes: IPv4 dotted decimal, IPv6 hexadecimal, static vs dynamic addressing and the role of DHCP.

Analysing Topologies and Performance

When evaluating topologies, consider failure points, installation cost, complexity, and performance. For example, a star topology is easy to manage and isolate faults but cabling can become expensive in large buildings. Mesh networks provide high fault tolerance yet demand more hardware and configuration expertise. Always tailor your evaluation to the scenario – for exam marks, mention how a star network in a college allows simple QoS policies for exam halls, or how a partial mesh might support critical services like a VLE.

Expect calculations: if a 500 MB file transfers over a LAN at 100 Mbps, convert 500 MB to 4,000 Mb, then divide by 100 Mb/s to get 40 seconds. Use correct units to impress examiners. Link performance choices to cybersecurity: a segmented VLAN reduces broadcast traffic and limits the spread of malware; direct students to our languages and IDEs post for understanding how developers use tools to profile networked software.

In longer answers, reference real design documents such as network diagrams or service-level agreements. Mention redundancy techniques (stacked switches, dual routers, UPS units) and monitoring tools (SNMP, NetFlow) to show awareness of operational realities. When comparing WAN options, evaluate leased lines versus MPLS or VPN over the internet, and justify your recommendation with cost, latency, and security considerations.

Example Question & Answer

Question: A college currently uses a bus topology for its admin LAN. They plan to support 200 additional student laptops and real-time video streaming from science labs. Evaluate whether they should migrate to a star or mesh topology, considering reliability, performance, and cost (8 marks).

Model answer: A bus topology cannot handle 200 extra devices without introducing collisions and latency spikes. Switching to a star topology places each device on its own segment connected to a central switch, drastically reducing collisions and easing troubleshooting. However, the central switch becomes a single point of failure. A full mesh would offer resilience and cope well with video streaming, yet it requires multiple NICs and significant cabling, increasing cost and complexity. A hybrid star with stacked switches provides a good compromise: manageable cabling, support for VLANs, and failover options. Therefore, migrating to an enhanced star configuration with redundant switches is the most cost-effective solution while meeting the new demands.

Common Mistakes & Tips

Confusing routers and switches: routers connect different networks (and use IP routing), while switches connect devices within the same network.
Forgetting to mention signal attenuation and the need for repeaters over long cable runs.
Describing Wi-Fi as “slower” without referencing frequency bands, interference, and security (WPA3 vs WPA2).
Overlooking the administrative overhead of peer-to-peer networks when asked about file sharing in a school.
Ignoring legal issues such as data protection when discussing remote access and WANs.
Neglecting to justify choices with user needs and budget constraints.
Failing to convert between Mbps and MB/s, leading to incorrect transfer time calculations.

Further Practice

Link to relevant site pages: