N10-009 Networking Concepts Practice Question
Which of the following is a characteristic of UDP when compared to TCP?
⚠ Common exam trap
Test-takers frequently confuse UDP's lack of reliability with it being 'unusable' or 'broken,' but the exam tests that UDP's lower overhead is a deliberate design choice for performance-sensitive applications where occasional packet loss is acceptable.
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
✓
C) UDP has lower overhead due to minimal header
UDP (User Datagram Protocol) has a minimal 8-byte header compared to TCP's 20-byte header, resulting in lower overhead and faster transmission. Unlike TCP, UDP does not provide reliability, flow control, or error recovery, making it ideal for real-time applications like VoIP or video streaming where speed is prioritized over guaranteed 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.
- ✗
A) UDP uses sequence numbers for ordering
Why it's wrong here
Unlike TCP, UDP does not incorporate sequence numbers within its header. This means UDP datagrams are transmitted independently without any inherent mechanism to track their order of arrival or detect missing packets, making it unsuitable for applications requiring guaranteed ordered delivery at the transport layer.
When this WOULD be correct
In a question asking 'Which protocol uses sequence numbers for ordering data segments?', TCP would be the correct answer, as it assigns sequence numbers to each byte for proper reassembly.
- ✗
B) UDP provides reliable data delivery
Why it's wrong here
UDP is fundamentally an unreliable, best-effort protocol, meaning it offers no guarantees that data will reach its destination, arrive in order, or be free of duplication. It lacks mechanisms such as acknowledgments, retransmissions, flow control, or congestion control, which are essential for ensuring data integrity and delivery reliability at the transport layer.
When this WOULD be correct
In a question asking 'Which protocol provides reliable data delivery?', TCP would be the correct answer, as it uses acknowledgments, sequence numbers, and retransmissions to ensure data arrives intact and in order.
- ✓
C) UDP has lower overhead due to minimal header
Why this is correct
UDP's minimal 8-byte header, containing only source and destination ports, length, and a checksum, significantly reduces protocol overhead compared to TCP's more complex 20-byte header. This streamlined structure, coupled with its connectionless nature, eliminates the need for connection establishment and state management, allowing for faster data transmission with less processing burden on network devices and endpoints.
- ✗
D) UDP requires a three-way handshake to establish a connection
Why it's wrong here
UDP operates as a connectionless protocol, which means it does not engage in a three-way handshake or any other form of connection establishment before sending data. Datagrams are simply sent to the destination without prior negotiation of parameters or state synchronization, contrasting sharply with TCP's connection-oriented setup that requires a handshake to initialize communication.
When this WOULD be correct
If the question asked 'Which of the following is a characteristic of TCP?' then option D would be correct, as TCP uses a three-way handshake to establish a reliable connection.
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 N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓C) UDP has lower overhead due to minimal headerCorrect answer▾
Why this is correct
UDP's minimal 8-byte header, containing only source and destination ports, length, and a checksum, significantly reduces protocol overhead compared to TCP's more complex 20-byte header. This streamlined structure, coupled with its connectionless nature, eliminates the need for connection establishment and state management, allowing for faster data transmission with less processing burden on network devices and endpoints.
✗A) UDP uses sequence numbers for orderingWrong answer — click to see why▾
Why this is wrong here
UDP does not use sequence numbers for ordering; that is a feature of TCP, which uses sequence numbers to ensure ordered delivery of data segments.
★ When this WOULD be the correct answer
In a question asking 'Which protocol uses sequence numbers for ordering data segments?', TCP would be the correct answer, as it assigns sequence numbers to each byte for proper reassembly.
Why candidates choose this
Candidates may confuse UDP with TCP, assuming both use sequence numbers, or they may recall that UDP can optionally use sequence numbers in some applications, but it is not a standard characteristic.
✗B) UDP provides reliable data deliveryWrong answer — click to see why▾
Why this is wrong here
UDP does not provide reliable data delivery; it is connectionless and offers no guarantees regarding packet delivery, ordering, or error recovery, unlike TCP which ensures reliability through acknowledgments and retransmissions.
★ When this WOULD be the correct answer
In a question asking 'Which protocol provides reliable data delivery?', TCP would be the correct answer, as it uses acknowledgments, sequence numbers, and retransmissions to ensure data arrives intact and in order.
Why candidates choose this
Candidates may confuse UDP with TCP due to incomplete understanding of transport layer protocols, mistakenly thinking all protocols provide reliability, or they may recall that UDP can be used with application-layer reliability mechanisms.
✗D) UDP requires a three-way handshake to establish a connectionWrong answer — click to see why▾
Why this is wrong here
UDP does not require a three-way handshake; it is connectionless and sends data without establishing a connection. The three-way handshake is a TCP mechanism for connection establishment.
★ When this WOULD be the correct answer
If the question asked 'Which of the following is a characteristic of TCP?' then option D would be correct, as TCP uses a three-way handshake to establish a reliable connection.
Why candidates choose this
Candidates may confuse UDP with TCP because both are transport layer protocols, and they might mistakenly think all transport protocols require a handshake, or they may not clearly remember which protocol uses the three-way handshake.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
TCP/IP Model and Protocol Suite
Key term
Session Initiation Protocol
Session Initiation Protocol (SIP) is a signaling protocol used to start, maintain, and end voice and video calls over IP networks.
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.
About these practice questions
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 exam.