Which of the following statements is TRUE about CSMA/CD

Correct statement: CSMA/CD is not suitable for a high propagation delay network like satellite network

Explanation:

• How CSMA/CD works: A station listens to the medium and transmits only if it is idle. If a collision occurs during transmission, stations detect it, send a jam signal, and use binary exponential backoff before retrying.

• Why CSMA/CD is unsuitable for high propagation delay: Collision detection requires that a transmitting station detect a collision while it is still sending. Large propagation delays (for example, satellite round‑trip times) mean collisions are detected too late or not at all unless frame sizes are made impractically long, so efficiency and reliability suffer.

• Wireless networks use CSMA/CA: IEEE 802.11 uses collision avoidance (CSMA/CA) because wireless stations generally cannot perform reliable collision detection.

• Ethernet and CSMA/CD: Traditional shared-medium Ethernet is based on CSMA/CD. Modern switched Ethernet reduces or eliminates collisions by providing separate collision domains for each link, but the original Ethernet MAC used CSMA/CD.

• Contention is inherent: CSMA/CD is contention-based: nodes contend for the medium, collisions occur, and the protocol resolves them with collision detection and backoff.

Summary: Because collision detection depends on short propagation delays relative to frame transmission time, CSMA/CD is not suitable for satellite or other high‑latency networks; alternative MAC strategies are used instead.