- A
UDP
Why wrong: UDP is connectionless and does not guarantee delivery or error recovery. It is used for applications where speed is more critical than reliability, such as streaming or VoIP.
- B
IP
Why wrong: IP operates at the Network layer and is responsible for addressing and routing packets. It does not provide transport-layer reliability.
- C
TCP
TCP provides reliable, ordered delivery of data with error checking and retransmission. It is the correct choice for file transfers where data integrity is critical.
- D
ICMP
Why wrong: ICMP is used for diagnostic and control messages, such as ping and traceroute. It does not transport application data reliably.
Question 345 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 engineer needs to transfer a large database file from one server to another across a WAN link. The transfer must be reliable and guarantee that the data arrives without errors. Which transport layer protocol should the engineer use?
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) is the correct choice because it provides reliable, connection-oriented data transfer with error checking, retransmission of lost packets, and in-order delivery. For a large database file transfer across a WAN link, TCP ensures the data arrives completely and without errors, which is essential for database integrity.
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.
- ✗
UDP
Why it's wrong here
UDP is connectionless and does not guarantee delivery or error recovery. It is used for applications where speed is more critical than reliability, such as streaming or VoIP.
When this WOULD be correct
A question requiring low-latency, real-time data transfer (e.g., streaming video or VoIP) where occasional packet loss is acceptable would make UDP the correct answer.
- ✗
IP
Why it's wrong here
IP operates at the Network layer and is responsible for addressing and routing packets. It does not provide transport-layer reliability.
When this WOULD be correct
A question asking which protocol is used for logical addressing and routing packets across networks, such as 'Which protocol provides logical addressing to enable communication between different networks?' would make IP the correct answer.
- ✓
TCP
Why this is correct
TCP provides reliable, ordered delivery of data with error checking and retransmission. It is the correct choice for file transfers where data integrity is critical.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
ICMP
Why it's wrong here
ICMP is used for diagnostic and control messages, such as ping and traceroute. It does not transport application data reliably.
When this WOULD be correct
A network engineer needs to verify connectivity and measure round-trip time between two servers across a WAN link. Which protocol should be used for this diagnostic purpose?
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
TCP provides reliable, ordered delivery of data with error checking and retransmission. It is the correct choice for file transfers where data integrity is critical.
✗UDPWrong answer — click to see why▾
Why this is wrong here
UDP is connectionless and does not provide error checking or retransmission, so it cannot guarantee reliable, error-free data transfer across a WAN link.
★ When this WOULD be the correct answer
A question requiring low-latency, real-time data transfer (e.g., streaming video or VoIP) where occasional packet loss is acceptable would make UDP the correct answer.
Why candidates choose this
Candidates may confuse 'fast' with 'reliable' and think UDP's speed makes it suitable for large file transfers, overlooking its lack of reliability guarantees.
✗IPWrong answer — click to see why▾
Why this is wrong here
IP is a network layer protocol (Layer 3) responsible for addressing and routing, not for reliable data transfer or error checking at the transport layer. It does not guarantee delivery or error-free transmission.
★ When this WOULD be the correct answer
A question asking which protocol is used for logical addressing and routing packets across networks, such as 'Which protocol provides logical addressing to enable communication between different networks?' would make IP the correct answer.
Why candidates choose this
Candidates may confuse IP with TCP because both are part of the TCP/IP suite, or they might think IP provides reliability since it is fundamental to internet communication.
✗ICMPWrong answer — click to see why▾
Why this is wrong here
ICMP is a network layer protocol used for error reporting and diagnostic functions (e.g., ping), not for reliable data transfer of files. It does not provide the error-free, ordered delivery required for database file transfer.
★ When this WOULD be the correct answer
A network engineer needs to verify connectivity and measure round-trip time between two servers across a WAN link. Which protocol should be used for this diagnostic purpose?
Why candidates choose this
Candidates may confuse ICMP's error-checking capability (e.g., checksums) with the reliability needed for data transfer, or think ICMP can be used for simple file transfers due to its low overhead.
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
The trap here is that candidates often confuse UDP with reliability because they associate it with 'fast' transfers, but Cisco tests the fundamental distinction that only TCP provides guaranteed, error-free delivery at the transport layer.
Detailed technical explanation
How to think about this question
TCP uses sequence numbers, acknowledgment (ACK) packets, and a sliding window mechanism to ensure reliable data transfer; if a segment is lost or corrupted, the receiver does not send an ACK, and the sender retransmits after a timeout. In a WAN environment, TCP's congestion control algorithms (e.g., TCP Reno, Cubic) dynamically adjust the transmission rate to avoid overwhelming the link, which is critical for large file transfers over high-latency or lossy paths.
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.
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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) is the correct choice because it provides reliable, connection-oriented data transfer with error checking, retransmission of lost packets, and in-order delivery. For a large database file transfer across a WAN link, TCP ensures the data arrives completely and without errors, which is essential for database integrity.
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 11, 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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