How does NETTCP improve retransmission strategies?

• A. By using duplicate acknowledgments
• B. By implementing fast retransmit and fast recovery techniques
• C. By reducing the number of retransmissions
• D. By increasing the timeouts between transmissions

Answer: (B)

The choice that indicates NETTCP improves retransmission strategies through the implementation of fast retransmit and fast recovery techniques is accurate because these methods specifically address the efficiency of handling packet loss in a network.

Fast retransmit is a mechanism designed to allow the sender to quickly retransmit packets that appear to have been lost, based on the receipt of duplicate acknowledgments by the sender. When the sender receives multiple duplicate acknowledgments for the same data packet, it interprets this as a likely indication that the transmitted packet was lost, prompting an immediate retransmission. This minimizes the waiting time that would typically occur if the sender relied solely on timeout intervals to determine packet loss.

Following the fast retransmit, fast recovery allows the sender to continue sending new packets instead of waiting for an acknowledgment of the retransmitted packet. This approach helps maintain throughput and avoid a substantial drop in performance when packet loss occurs, making the transmission more efficient overall.

The other options, while they may touch on concepts related to retransmission, do not encapsulate the specific strategic improvements that NETTCP employs through these well-defined techniques. Duplicate acknowledgments serve as an indicator in this strategy, but they are not a method themselves for improving retransmission. Reducing the number of retransmissions may be a goal,