TCP is the correct choice because it provides reliable data transfer through connection-oriented communication, error checking via checksums, automatic retransmission of lost packets, and in-order delivery—all essential for guaranteeing that a large database file arrives intact across a WAN link. On the CompTIA Network+ N10-009 exam, this concept tests your understanding of transport layer protocols and their appropriate use cases; a common trap is choosing UDP for speed, but remember that file transfers requiring data integrity must use TCP. The exam often contrasts TCP’s reliability with UDP’s speed in scenarios like streaming or VoIP. For a quick memory tip, think “TCP Takes Care of Packets”—it ensures every segment is acknowledged and retransmitted if lost, making it the go-to for error-free file transfers.
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?
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.
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.
✗
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.
✓
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.
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.
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: 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.
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Question Discussion
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