What is the difference regarding reliability and communication type between TCP and UDP?
Correct Answer: A
TCP is reliable and connection-oriented; UDP is connectionless and does not provide transport-layer reliability. TCP establishes a session before data transfer and uses sequence numbers, acknowledgments, retransmissions, and flow control. That behavior is useful for applications that cannot tolerate missing or out- of-order data, such as file transfers, web sessions, and many application transactions. UDP avoids session establishment and reliability tracking. It sends datagrams with less overhead, which is useful for DNS, DHCP, streaming, voice, and other traffic where speed or application-level handling is preferred. Cisco CCNA 200-
301 v1.1 Network Fundamentals expects this contrast to be automatic. The incorrect choices reverse reliability or connection behavior. Do not confuse UDP ' s checksum with reliable delivery; a checksum can detect corruption, but it does not guarantee retransmission or ordering. In the language of the answer options, TCP is reliable and connection-oriented, while UDP is not reliable and is connectionless.