Question 1,954 of 2,015

Model-Driven Telemetry →mediumMultiple ChoiceObjective-mapped

350-401 Model-Driven Telemetry Practice Question

This 350-401 practice question tests your understanding of model-driven telemetry. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 is troubleshooting a model-driven telemetry deployment on a Cisco IOS-XE router. The telemetry subscription is configured to stream interface statistics using gRPC dial-out to a collector at 10.1.1.100:50051. The engineer verifies that the collector is listening on the port and the router can reach it. However, the collector shows no data received. The engineer checks the router's telemetry logs and sees 'Connection refused' errors. What is the most likely cause?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

Question 1mediummultiple choice

Read the full network assurance explanation →

A
The collector's firewall is blocking the connection from the router
Why wrong: If the firewall were blocking, the error would likely be 'No route to host' or timeout, not 'Connection refused'.
B
The gRPC server on the collector is not running or is listening on a different port
'Connection refused' occurs when the TCP SYN reaches the host but no application is listening on the specified port.
C
The telemetry subscription is missing the 'encoding' configuration
Why wrong: Missing encoding would not cause a connection refusal; the router would still attempt to connect.
D
The router's source-interface is not configured, causing the router to use an unreachable IP
Why wrong: If the source IP were unreachable, the error would be 'No route to host' or timeout, not 'Connection refused'.

Full breakdown with real-world context →

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

✓

The gRPC server on the collector is not running or is listening on a different port

The correct answer is that the collector is not configured to accept gRPC connections, or the gRPC server on the collector is not running. The 'Connection refused' error indicates that the TCP connection is being rejected, typically because the collector's gRPC server is not listening on that port. The other options are incorrect because the router can reach the collector, so firewall is not blocking; the subscription is configured correctly; and the encoding is not the cause of connection refusal.

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.

✗
The collector's firewall is blocking the connection from the router
Why it's wrong here
If the firewall were blocking, the error would likely be 'No route to host' or timeout, not 'Connection refused'.
✓
The gRPC server on the collector is not running or is listening on a different port
Why this is correct
'Connection refused' occurs when the TCP SYN reaches the host but no application is listening on the specified port.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The telemetry subscription is missing the 'encoding' configuration
Why it's wrong here
Missing encoding would not cause a connection refusal; the router would still attempt to connect.
✗
The router's source-interface is not configured, causing the router to use an unreachable IP
Why it's wrong here
If the source IP were unreachable, the error would be 'No route to host' or timeout, not 'Connection refused'.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.

Detailed technical explanation

How to think about this question

This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.

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.
Use explanations to understand the rule behind the answer.

TExam Day Tips

Underline the problem statement mentally.
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 350-401 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.

What to study next

Got this wrong? Here's your next step.

Identify which 350-401 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.

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FAQ

Questions learners often ask

What does this 350-401 question test?

Model-Driven Telemetry — This question tests Model-Driven Telemetry — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The gRPC server on the collector is not running or is listening on a different port — The correct answer is that the collector is not configured to accept gRPC connections, or the gRPC server on the collector is not running. The 'Connection refused' error indicates that the TCP connection is being rejected, typically because the collector's gRPC server is not listening on that port. The other options are incorrect because the router can reach the collector, so firewall is not blocking; the subscription is configured correctly; and the encoding is not the cause of connection refusal.

What should I do if I get this 350-401 question wrong?

Are there clue words in this question I should notice?

Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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