How are networks physically arranged, and what hardware connects them?
Star and mesh network topologies and their advantages and disadvantages, and the role of network hardware (NIC, switch, router, wireless access point and transmission media).
An OCR J277 1.3.1 answer on star and mesh network topologies (with advantages and disadvantages) and the role of network hardware: the NIC, switch, router, wireless access point and transmission media.
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What this dot point is asking
OCR wants you to describe the star and mesh topologies with their advantages and disadvantages, and to state the role of the common network hardware. The topology comparison is a frequent higher-tariff question, and the hardware roles must be precise (especially switch versus router).
Star topology
Mesh topology
Network hardware
Choosing a topology
The choice balances reliability against cost. A star is the usual choice for a home, school or office because it is reliable, fast and easy to manage, accepting that the central switch is a single point of failure. A mesh is chosen where reliability is critical and a break must not stop communication, accepting the higher cost and complexity; wireless mesh makes this cheaper for things like smart-home or large-area Wi-Fi coverage. The hardware roles do not change with topology: you still need NICs, and a switch and router to direct and route data.
Try this
Q1. State one advantage and one disadvantage of a star topology. [2 marks]
- Cue. Advantage: one failed cable affects only that device. Disadvantage: the network fails if the central switch fails.
Q2. State why a mesh topology is very reliable. [1 mark]
- Cue. There are multiple paths, so data can be rerouted if one connection fails; there is no single point of failure.
Q3. State the role of a router. [1 mark]
- Cue. It connects different networks and forwards data between them using IP addresses.
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20206 marksDescribe the star topology and the mesh topology, giving one advantage and one disadvantage of each.Show worked answer →
Star topology: every device connects to a central switch (or hub), which directs the data. Advantage (one mark): if one cable or device fails, only that device is affected and the rest of the network keeps working; it is also easy to add new devices. Disadvantage (one mark): if the central switch fails, the whole network goes down, and a switch plus cabling to every device adds cost.
Mesh topology: devices are connected to many other devices, so there are multiple paths for data. Advantage (one mark): it is very reliable because if one connection fails, data is rerouted along another path; there is no single point of failure. Disadvantage (one mark): a full mesh needs a very large number of connections, so it is expensive and complex to set up and maintain.
Markers reward a correct description of each topology and a valid advantage and disadvantage for each (4 description/structure marks plus the advantage/disadvantage points up to six).
OCR 20234 marksState the role of each of the following pieces of network hardware: a network interface card (NIC), a switch, a router and a wireless access point (WAP).Show worked answer →
Award one mark for each correct role, up to four.
NIC (network interface card): allows a device to connect to a network, giving it the hardware (and a MAC address) needed to send and receive data.
Switch: connects devices on a LAN and directs data only to the specific device it is addressed to, using MAC addresses, rather than to all devices.
Router: connects different networks together and directs data between them (for example connecting a home LAN to the internet), forwarding data using IP addresses.
WAP (wireless access point): allows wireless devices to connect to a wired network by sending and receiving radio signals.
Markers reward precise roles. Saying a switch "sends data to all devices" describes a hub, not a switch, and loses the mark.
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Sources & how we know this
- OCR GCSE (9-1) Computer Science (J277) specification — OCR (2020)