This N10-009 practice question tests your understanding of networking concepts. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network technician is explaining the difference between connection-oriented and connectionless protocols to a junior technician. Which of the following protocols is connectionless at the transport layer?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
UDP
UDP (User Datagram Protocol) is the correct answer because it is a connectionless transport-layer protocol. It does not establish a session or guarantee delivery, instead sending datagrams independently without handshaking or acknowledgments, which makes it suitable for real-time applications like VoIP and streaming.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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
Why it's wrong here
TCP is connection-oriented; it uses a three-way handshake to establish a session before data transfer.
✓
UDP
Why this is correct
UDP is a connectionless protocol; it sends data without establishing a connection, making it faster but less reliable.
Related concept
Read the scenario before looking for a memorised answer.
✗
ICMP
Why it's wrong here
ICMP is a network-layer protocol used for diagnostics (e.g., ping), not a transport-layer protocol.
✗
ARP
Why it's wrong here
ARP is a data-link layer protocol used to resolve IP addresses to MAC addresses; it does not operate at the transport layer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse ICMP or ARP as transport-layer protocols because they are involved in network communication, but the question specifically asks for the transport layer, where only TCP and UDP reside, and UDP is the connectionless one.
Detailed technical explanation
How to think about this question
UDP uses a minimal 8-byte header with source/destination ports, length, and checksum, and relies on application-layer logic for reliability if needed. In real-world scenarios, DNS queries use UDP by default (port 53) to reduce latency, falling back to TCP only when responses exceed 512 bytes or for zone transfers. The connectionless nature means no sequence numbers or flow control, so packet loss is handled by the application, as seen in real-time video streaming where a lost frame is preferable to retransmission delays.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the N10-009 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this N10-009 question in full detail.
Networking Concepts — This question tests Networking Concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: UDP — UDP (User Datagram Protocol) is the correct answer because it is a connectionless transport-layer protocol. It does not establish a session or guarantee delivery, instead sending datagrams independently without handshaking or acknowledgments, which makes it suitable for real-time applications like VoIP and streaming.
What should I do if I get this N10-009 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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