UDP Characteristics for Network+: Connectionless Protocol, Low Overhead vs TCP
Which of the following is a characteristic of UDP?
Quick Answer
Lower overhead than TCP is the defining characteristic being tested here, and it comes directly from what UDP deliberately leaves out. TCP spends extra packets and processing establishing a connection through its three-way handshake, then continues spending overhead throughout the session on features like sequencing, acknowledgments, flow control, and retransmission of lost data to guarantee reliable delivery. UDP skips all of that: it has a much smaller header, sends data immediately without any handshake, and never checks whether packets arrived or arrived in order. That absence of reliability mechanics is exactly what makes it lower overhead, and it's also why UDP suits real-time applications like voice or video streaming, where a lost or late packet is more disruptive to retransmit than to simply skip. This is the trade-off to keep straight for the exam: TCP's overhead buys guaranteed, ordered delivery, while UDP's minimalism buys speed at the cost of any delivery guarantee. Any exam question describing a protocol chosen specifically for its speed, minimal overhead, or suitability for time-sensitive traffic where occasional dropped data is acceptable is describing UDP's core trade-off against TCP, and recognizing that overhead-versus-reliability trade-off is the fastest way to identify which protocol a scenario is pointing toward.
⚠ Common exam trap
Candidates often confuse UDP's lack of reliability with being 'unreliable' in a negative sense, but the exam tests that UDP's lower overhead is a deliberate design choice for performance-sensitive applications.
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
✓
Has lower overhead than TCP
UDP (User Datagram Protocol) is a connectionless transport-layer protocol that provides minimal overhead compared to TCP. It does not establish a connection before sending data, nor does it provide reliability, flow control, or error recovery, making it ideal for real-time applications like VoIP and 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.
- ✗
Provides guaranteed delivery
Why it's wrong here
UDP is best-effort; guaranteed delivery is a characteristic of TCP.
When this WOULD be correct
In a question asking 'Which of the following is a characteristic of TCP?', 'Provides guaranteed delivery' would be correct because TCP uses acknowledgments and retransmissions to ensure data arrives intact.
- ✗
Uses sequence numbers
Why it's wrong here
Sequence numbers are used by TCP for ordering and reliability.
When this WOULD be correct
In a question asking 'Which of the following is a characteristic of TCP?', option 'Uses sequence numbers' would be correct because TCP uses sequence numbers to ensure ordered data delivery.
- ✗
Supports three-way handshake
Why it's wrong here
The three-way handshake is part of TCP connection establishment.
When this WOULD be correct
In a question asking 'Which of the following is a characteristic of TCP?', option C would be correct because TCP uses a three-way handshake to establish a connection.
- ✓
Has lower overhead than TCP
Why this is correct
UDP has minimal header size and no connection establishment, resulting in lower overhead.
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.
✓Has lower overhead than TCPCorrect answer▾
Why this is correct
UDP has minimal header size and no connection establishment, resulting in lower overhead.
✗Provides guaranteed deliveryWrong answer — click to see why▾
Why this is wrong here
UDP is a connectionless protocol that does not provide guaranteed delivery; it offers no acknowledgments or retransmissions, unlike TCP which ensures reliable data transfer.
★ When this WOULD be the correct answer
In a question asking 'Which of the following is a characteristic of TCP?', 'Provides guaranteed delivery' would be correct because TCP uses acknowledgments and retransmissions to ensure data arrives intact.
Why candidates choose this
Candidates may confuse UDP with TCP, assuming all transport protocols provide reliability, or they may think 'best-effort' delivery implies some guarantee.
✗Uses sequence numbersWrong answer — click to see why▾
Why this is wrong here
UDP is a connectionless protocol that does not use sequence numbers; sequence numbers are a feature of TCP for ordered delivery.
★ When this WOULD be the correct answer
In a question asking 'Which of the following is a characteristic of TCP?', option 'Uses sequence numbers' would be correct because TCP uses sequence numbers to ensure ordered data delivery.
Why candidates choose this
Candidates may confuse UDP with TCP, assuming all transport protocols use sequence numbers for reliability, or they may recall that UDP has a checksum but mistakenly think it includes sequence numbers.
✗Supports three-way handshakeWrong answer — click to see why▾
Why this is wrong here
UDP is a connectionless protocol that does not establish a session, so it does not support a three-way handshake, which is a TCP mechanism.
★ When this WOULD be the correct answer
In a question asking 'Which of the following is a characteristic of TCP?', option C would be correct because TCP uses a three-way handshake to establish a connection.
Why candidates choose this
Candidates may confuse UDP with TCP, as both are transport layer protocols, and mistakenly attribute TCP features like the three-way handshake to UDP.
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?”
Visual reference
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Related to this question
Learn chapter
TCP/IP Model and Protocol Suite
Key term
VoIP
VoIP (Voice over IP) is a technology that transmits voice calls as digital data packets over IP networks instead of traditional circuit-switched telephone lines.
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.
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Same concept, more angles
1 more way this is tested on N10-009
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which of the following is a characteristic of a connectionless protocol at the transport layer?
easy- A.It establishes a session before sending data
- B.It guarantees delivery using acknowledgments
- ✓ C.It does not require a virtual circuit
- D.It retransmits lost segments
Why C: Connectionless protocols at the transport layer, such as UDP (User Datagram Protocol), do not establish a virtual circuit or session before sending data. Each datagram is sent independently without prior coordination, making the protocol stateless and reducing overhead. This characteristic is fundamental to UDP's design, as defined in RFC 768.
JA
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.