Cisco Certified Network Associate (CCNA) Practice Exam

Which of the following is a characteristic of a shared collision domain?

1. All devices can communicate simultaneously

2. Devices use a token passing method

3. Data collisions can occur

4. Utilizes nondedicated bandwidth

The correct answer is: Data collisions can occur

A shared collision domain is a network segment where multiple devices can attempt to send data at the same time, which can lead to data collisions. When two or more devices transmit simultaneously in this environment, the signals can interfere with each other, causing a collision. This phenomenon is a fundamental characteristic of traditional Ethernet networks operating in half-duplex mode, where only one device can successfully send data at a time. The nature of a shared collision domain means that nodes must compete for the network medium, and when collisions occur, the devices involved must follow a protocol, like CSMA/CD (Carrier Sense Multiple Access with Collision Detection), to detect the collision and retransmit their data after a random backoff period. This characteristic makes it clear why data collisions are endemic to shared collision domains, as they lack the mechanism to fully isolate traffic. In contrast, simultaneous communication or token passing is indicative of network architectures designed to manage bandwidth more efficiently without collisions. Thus, while the scenario of a shared collision domain inherently allows for collisions, other options do not describe its fundamental nature.