In computer networking, what is meant by a passive topology in the context of physical network layout?

Introduction / Context:
Network topologies describe how devices are physically or logically arranged and how signals travel through the network. Some devices actively participate in signal regeneration and routing, while others are passive and only tap into the existing signal. Understanding the concept of a passive topology helps distinguish between different physical arrangements such as bus, star, and ring. This question focuses on defining passive topology in clear, conceptual terms.

Given Data / Assumptions:

• Physical topology refers to the arrangement of cables and hardware in a network.
• Some network components, such as repeaters or switches, are active devices that regenerate or process signals.
• Other components, such as simple taps or connectors, do not modify the signal; they simply allow devices to listen.
• The question uses the phrase passive topology and expects an explanation that reflects this behaviour.

Concept / Approach:
A passive topology is one in which the network devices connected to the medium do not play an active role in regenerating or routing the signal. Instead, the medium carries the signal, and each device listens to it, reading frames addressed to that device and ignoring others. Classic shared bus Ethernet with coaxial cable is a good example, where the cable carries signals and each node taps in passively. Active devices, in contrast, regenerate or route signals, changing timing or strength. Therefore, the correct definition must emphasise that nodes do not regenerate, amplify, or actively forward the signal in a passive topology.

Step-by-Step Solution:
Step 1: Consider what the word passive suggests: nodes are not actively boosting or switching the signal. Step 2: Recall that in passive topologies, devices are connected by a medium that carries signals, and each node simply receives the shared signal. Step 3: Recognise that bus topologies with a simple backbone and taps are the classic example of passive behaviour. Step 4: Evaluate option a, which states that nodes listen to the signal and do not regenerate or actively route data as it passes across the medium. Step 5: Reject other options that describe topologies with many routers, active repeaters, or complex processing hubs.

Verification / Alternative check:
In textbooks, passive topology is often contrasted with active topology. In an active topology, intermediate devices such as repeaters or switches amplify or regenerate signals. In a passive topology like a traditional bus, the cable itself does the work of signal transmission, while nodes simply attach. Looking at diagrams and explanations confirms that the essential property of passive topology is the lack of signal regeneration by intermediate nodes.

Why Other Options Are Wrong:
Option b describes a network with many routers, which would be highly active, not passive. Option c talks about a wireless topology with only active repeaters, again contradicting the passive concept. Option d describes a hub that performs complex processing, which would also be an active element rather than passive.

Common Pitfalls:
Students sometimes confuse passive topology with passive devices like simple hubs or concentrators. While some hubs are electrically active, the topology can still be considered passive if the intermediate connections primarily just distribute signals without complex processing. The key is to focus on whether nodes themselves regenerate or route signals. In a passive topology, they do not; they only listen and transmit without altering the passing signal for others.

Final Answer:
A passive topology is a network topology in which the nodes simply listen to the signal and do not regenerate, amplify, or actively route the data as it passes across the medium.