In multiple-access networks, what does the term "contention" specifically describe?

Introduction / Context:
Access to a shared medium requires rules to prevent or resolve conflicts. This question focuses on the definition of contention, a central concept underlying contention-based protocols such as CSMA/CD and CSMA/CA used in LANs and WLANs.

Given Data / Assumptions:

• Stations share a common communication medium.
• There is no centralized schedule assigning exclusive transmission slots.
• Simultaneous attempts can occur due to random backoff outcomes or lack of carrier detection.

Concept / Approach:

Contention refers to competition for a shared resource. In networking, it occurs when two or more stations transmit (or attempt to transmit) over the same channel concurrently, which may lead to collisions or interference unless the protocol detects and mitigates it.

Step-by-Step Solution:

Verification / Alternative check:

Ethernet history shows CSMA/CD detecting collisions when contention occurs; Wi-Fi uses CSMA/CA to reduce the probability of contention-induced collisions.

Why Other Options Are Wrong:

Bus conductor definition: Describes topology, not contention.

Continuous frequency: Describes a carrier, unrelated to access conflicts.

Collection of units providing communications: Describes a network, not the access condition.

None of the above: Incorrect because the contention definition is present.

Common Pitfalls:

Conflating contention (the condition) with collision (the outcome). Contention can exist even when a protocol prevents collisions via backoff.

Final Answer:

The condition when two or more stations attempt to use the same channel at the same time