CCNA: Cisco Certified Network Associate — Question 206

How do TCP and UDP differ in the way they guarantee packet delivery?

Answer options

• A. TCP uses retransmissions, acknowledgment, and parity checks, and UDP uses cyclic redundancy checks only
• B. TCP uses two-dimensional parity checks, checksums, and cyclic redundancy checks, and UDP uses retransmissions only
• C. TCP uses checksum, acknowledgements, and retransmissions, and UDP uses checksums only
• D. TCP uses checksum, parity checks, and retransmissions, and UDP uses acknowledgements only

Correct answer: C

Explanation

The correct answer is C because TCP ensures reliable delivery through the use of checksums, acknowledgments, and retransmissions, while UDP does not guarantee delivery and only uses checksums for error-checking. The other options incorrectly describe the mechanisms used by TCP and UDP, such as including parity checks or misrepresenting the functionalities of the protocols.