Cisco Certified Network Associate (CCNA) Practice Exam

Which statement is true for half-duplex Ethernet?

1. It allows simultaneous sending and receiving of data

2. It operates in a shared collision domain

3. It requires a dedicated circuit

4. It always utilizes maximum throughput

The correct answer is: It operates in a shared collision domain

The correct statement regarding half-duplex Ethernet is that it operates in a shared collision domain. In a half-duplex communication system, devices can either send or receive data at any given time, but not both simultaneously. This results in the possibility of collisions occurring when two devices attempt to send data at the same time, hence the term "shared collision domain." In such a setup, devices must wait for the medium to be clear before they can transmit data, which can lead to delays. The nature of half-duplex allows for simpler implementation compared to full-duplex systems, which require more complex handling to manage simultaneous data flows. Half-duplex systems do not require a dedicated circuit; they share the bandwidth with other devices, which reinforces the point that they operate within a shared environment. While maximum throughput can be high under optimal conditions, the reality is that the presence of potential collisions can reduce effective throughput, making it not a guarantee for every scenario.