CCNA Network Infrastructure and Connectivity Practice Question
Which two statements accurately compare TCP and UDP? (Choose two.)
⚠ Common exam trap
Be careful not to confuse the connection-oriented nature of TCP with UDP's connectionless design. Remember that TCP is about reliability, while UDP focuses on speed and simplicity.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
TCP provides connection-oriented transport
TCP is connection-oriented and uses sequencing, acknowledgments, and related controls. UDP is simpler and has lower overhead, but it does not guarantee delivery.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
TCP provides connection-oriented transport
Why this is correct
TCP establishes a reliable, connection-oriented session by utilising a three-way handshake before any data transmission commences. This fundamental mechanism ensures a logical connection is set up and maintained between the communicating hosts, providing statefulness and ordered delivery. This precise characteristic directly contrasts with UDP's connectionless nature, making it an accurate comparison between the two protocols and satisfying the question's requirement for a distinguishing statement.
- ✗
UDP guarantees delivery through acknowledgments
Why it's wrong here
UDP is a connectionless, best-effort protocol that does not use acknowledgments, sequence numbers, or retransmission timers. Delivering datagrams with guaranteed reliability is handled exclusively by TCP, which uses cumulative acknowledgments and retransmission of lost segments. Therefore, stating that UDP guarantees delivery through acknowledgments is factually incorrect.
When this WOULD be correct
In a hypothetical question asking about a protocol that ensures reliable delivery through acknowledgments, such as TCP, option B would be correct. For example, a question might ask which protocol guarantees message delivery in a streaming application.
- ✓
UDP has lower overhead than TCP
Why this is correct
UDP has lower overhead than TCP because its fixed header is only 8 bytes, whereas TCP's header is at least 20 bytes and includes sequence numbers, acknowledgment numbers, and window fields. Additionally, UDP performs no three-way handshake or session state tracking, eliminating the extra control-message traffic and state-management resources that TCP must consume. This makes UDP a lighter protocol per datagram, though at the cost of reliability.
- ✗
TCP does not use port numbers
Why it's wrong here
TCP absolutely uses port numbers; each TCP segment header contains a 16-bit source port and a 16-bit destination port that identify the sending and receiving applications. Without these port numbers, the operating system would be unable to demultiplex incoming TCP traffic to the correct process, so port numbers are a core element of TCP's design. This statement confuses TCP with a hypothetical protocol that lacks addressing for application multiplexing.
When this WOULD be correct
In a different exam question that specifically asks about a transport protocol that does not use port numbers, such as a hypothetical protocol designed for a specific application without the need for multiplexing, option D would be correct.
- ✗
UDP is always faster because it avoids congestion
Why it's wrong here
UDP avoids congestion control mechanisms, allowing an application to send datagrams at the chosen rate without backing off on packet loss. However, 'always faster' is an absolute claim that fails in real networks: throughput depends on link bandwidth, latency, packet loss, and whether the application itself implements reliability. A UDP stream that is lossy may require application-level retransmission and could end up slower than a well-tuned TCP transfer, so the statement is not technically sound.
When this WOULD be correct
In a different exam scenario where the question asks about the performance characteristics of various transport protocols under specific conditions, such as low-latency networks or real-time applications, this option could be correct if it emphasizes that UDP's design allows for faster data transmission in those contexts.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓TCP provides connection-oriented transportCorrect answer▾
Why this is correct
TCP establishes a reliable, connection-oriented session by utilising a three-way handshake before any data transmission commences. This fundamental mechanism ensures a logical connection is set up and maintained between the communicating hosts, providing statefulness and ordered delivery. This precise characteristic directly contrasts with UDP's connectionless nature, making it an accurate comparison between the two protocols and satisfying the question's requirement for a distinguishing statement.
✗UDP guarantees delivery through acknowledgmentsWrong answer — click to see why▾
Why this is wrong here
UDP is a connectionless protocol that does not use acknowledgments, sequence numbers, or retransmissions; it simply sends datagrams without any guarantee of delivery. Reliable delivery mechanisms like acknowledgments are a feature of TCP, not UDP.
★ When this WOULD be the correct answer
In a hypothetical question asking about a protocol that ensures reliable delivery through acknowledgments, such as TCP, option B would be correct. For example, a question might ask which protocol guarantees message delivery in a streaming application.
Why candidates choose this
Students may confuse UDP's lack of reliability with the idea that it still provides some form of delivery confirmation, or they might think that all transport protocols use acknowledgments because TCP does.
✗TCP does not use port numbersWrong answer — click to see why▾
Why this is wrong here
TCP uses port numbers extensively to identify source and destination applications, just like UDP. Port numbers are a fundamental part of both TCP and UDP headers, enabling multiplexing of multiple services on a single host.
★ When this WOULD be the correct answer
In a different exam question that specifically asks about a transport protocol that does not use port numbers, such as a hypothetical protocol designed for a specific application without the need for multiplexing, option D would be correct.
Why candidates choose this
A student might incorrectly associate port numbers only with UDP because of the phrase 'UDP port numbers' commonly used, or they might think TCP's connection-oriented nature somehow replaces the need for port numbers.
✗UDP is always faster because it avoids congestionWrong answer — click to see why▾
Why this is wrong here
While UDP has lower overhead and can be faster in some scenarios, it is not 'always faster' because network congestion, packet loss, and application behavior can affect performance. Additionally, UDP does not inherently avoid congestion; it simply does not implement congestion control, which can lead to network congestion if used aggressively.
★ When this WOULD be the correct answer
In a different exam scenario where the question asks about the performance characteristics of various transport protocols under specific conditions, such as low-latency networks or real-time applications, this option could be correct if it emphasizes that UDP's design allows for faster data transmission in those contexts.
Why candidates choose this
The statement 'UDP is faster' is a common oversimplification. Students may assume that because UDP has less overhead, it is always faster, ignoring factors like retransmissions in TCP that can actually improve throughput in lossy networks.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Key term
TCP
TCP (Transmission Control Protocol) is a core internet protocol that ensures data is sent reliably and in order between devices over a network.
Key term
UDP
UDP (User Datagram Protocol) is a communication protocol that sends data quickly without first checking if the receiver is ready or if the data arrived correctly.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.