- A
IP
Why wrong: IP operates at the Network layer (Layer 3), not the Transport layer.
- B
TCP
Correct. TCP operates at the Transport layer (Layer 4) and provides reliable, connection-oriented communication with segmentation and reassembly.
- C
Ethernet
Why wrong: Ethernet operates at the Data Link layer (Layer 2) and Physical layer.
- D
HTTP
Why wrong: HTTP operates at the Application layer (Layer 7).
Question 237 of 520
N10-009 Networking Concepts Practice Question
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 OSI model to a junior technician. The technician mentions that the Transport layer is responsible for end-to-end communication and data segmentation. Which protocol operates at the Transport layer?
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
TCP (Transmission Control Protocol) operates at Layer 4 (Transport) of the OSI model, providing reliable, connection-oriented end-to-end communication and data segmentation with sequencing and acknowledgment. It ensures data is delivered error-free and in order, directly fulfilling the described responsibilities.
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.
- ✗
IP
Why it's wrong here
IP operates at the Network layer (Layer 3), not the Transport layer.
When this WOULD be correct
A question asking 'Which protocol is responsible for logical addressing and routing between networks?' would make IP the correct answer, as it operates at the Network layer.
- ✓
TCP
Why this is correct
Correct. TCP operates at the Transport layer (Layer 4) and provides reliable, connection-oriented communication with segmentation and reassembly.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Ethernet
Why it's wrong here
Ethernet operates at the Data Link layer (Layer 2) and Physical layer.
When this WOULD be correct
A question asking 'Which protocol operates at the Data Link layer of the OSI model?' would make Ethernet the correct answer, as it defines framing, MAC addressing, and media access control.
- ✗
HTTP
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.
✓TCPCorrect answer▾
Why this is correct
Correct. TCP operates at the Transport layer (Layer 4) and provides reliable, connection-oriented communication with segmentation and reassembly.
✗IPWrong answer — click to see why▾
Why this is wrong here
IP operates at the Network layer (Layer 3), not the Transport layer. It handles routing and addressing, not end-to-end communication and data segmentation.
★ When this WOULD be the correct answer
A question asking 'Which protocol is responsible for logical addressing and routing between networks?' would make IP the correct answer, as it operates at the Network layer.
Why candidates choose this
Candidates often confuse IP with TCP because they are commonly paired (TCP/IP), leading them to mistakenly associate IP with Transport layer functions.
✗EthernetWrong answer — click to see why▾
Why this is wrong here
Ethernet operates at the Data Link layer (Layer 2) and the Physical layer (Layer 1), not the Transport layer (Layer 4). It handles local network framing and media access, not end-to-end communication or segmentation.
★ When this WOULD be the correct answer
A question asking 'Which protocol operates at the Data Link layer of the OSI model?' would make Ethernet the correct answer, as it defines framing, MAC addressing, and media access control.
Why candidates choose this
Candidates may confuse Ethernet with TCP/IP because both are fundamental to networking, or they might think Ethernet handles data delivery across networks, not realizing it is limited to local segments.
✗HTTPWrong answer — click to see why▾
Why this is wrong here
HTTP operates at the Application layer (Layer 7) of the OSI model, not the Transport layer. The Transport layer is responsible for end-to-end communication and segmentation, which is handled by protocols like TCP and UDP.
★ When this WOULD be the correct answer
If the question asked 'Which protocol operates at the Application layer of the OSI model?' or 'Which protocol is used for web traffic?', then HTTP would be the correct answer.
Why candidates choose this
Candidates may confuse HTTP with TCP because HTTP relies on TCP for reliable transport, or they might mistakenly think HTTP is a transport protocol due to its common association with network communication.
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?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the distinction between TCP and UDP at the Transport layer, but here the trap is that candidates confuse IP (Layer 3) with Transport layer protocols because IP is fundamental to networking, yet it does not perform end-to-end communication or segmentation.
Detailed technical explanation
How to think about this question
TCP segments data by breaking it into units called segments, each with a header containing source and destination port numbers (16-bit fields), sequence numbers, and acknowledgment numbers to manage reliable delivery. The Transport layer also provides flow control via TCP's sliding window mechanism and error recovery through retransmission of lost segments, as defined in RFC 793. In contrast, UDP (also at Layer 4) offers a simpler, connectionless service without segmentation guarantees, highlighting that not all Transport protocols handle segmentation identically.
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.
Visual reference
Quick reference
OSI Model Reference
| Layer | Name | PDU | Key Protocols / Devices |
|---|---|---|---|
| 7 | Application | Data | HTTP, HTTPS, DNS, SMTP, FTP, SSH |
| 6 | Presentation | Data | TLS / SSL, JPEG, ASCII encoding |
| 5 | Session | Data | NetBIOS, RPC, SIP |
| 4 | Transport | Segment / Datagram | TCP, UDP |
| 3 | Network | Packet | IP, ICMP, OSPF — Routers |
| 2 | Data Link | Frame | Ethernet, Wi-Fi, PPP — Switches, Bridges |
| 1 | Physical | Bits | Cables, NICs, Hubs, Repeaters |
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this N10-009 question test?
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: TCP — TCP (Transmission Control Protocol) operates at Layer 4 (Transport) of the OSI model, providing reliable, connection-oriented end-to-end communication and data segmentation with sequencing and acknowledgment. It ensures data is delivered error-free and in order, directly fulfilling the described responsibilities.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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Last reviewed: Jun 30, 2026
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.
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