TCP and ______________ are the two most commonly used TCP/IP transport layer protocols.

(A) UDP
(B) HTTP
(C) DNS
(D) SMTP

Answer:

UDP is the correct answer.
Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are two most commonly used TCP/IP transport layer protocols. Each TCP/IP application typically chooses to use either TCP or UDP based on the application’s requirements.

For example, TCP provides error recovery, but to do so, it consumes more bandwidth and uses more processing cycles. UDP does not perform error recovery, but it takes less bandwidth and uses fewer processing cycles. TCP/IP Transport Layer Features are Multiplexing using ports, Error recovery (reliability), Flow control using windowing, Connection establishment, and termination, and Ordered data transfer and data segmentation.