In which scenario is RTS/CTS typically most beneficial?

• A. In networks with perfect carrier sensing and no hidden nodes.
• B. Only during initial device association.
• C. When all clients are stationary and request low data rates.
• D. In networks with hidden nodes to prevent collisions.

Answer: (D)

RTS/CTS is a short control handshake used to prevent collisions in wireless networks by reserving the channel before sending data. It shines when there are hidden nodes—situations where two devices can’t hear each other but can both hear a common receiver. Without RTS/CTS, those two devices might transmit at the same time, causing a collision at the receiver. By sending an RTS from the sender and a CTS from the receiver, nearby devices learn to defer their transmissions, dramatically reducing the chance of collisions.

That’s why it’s most beneficial in networks with hidden nodes: the collision reduction payoff is highest there. If sensing is perfect and no hidden nodes exist, the overhead of RTS/CTS isn’t worth it. It isn’t specifically tied to initial association, and while low data rates with stationary clients reduce some dynamic traffic issues, the decisive factor is the presence of hidden terminals.