The answer is to configure an on-change subscription. This parameter ensures that telemetry data is streamed only when a monitored value, such as an interface counter, actually changes, rather than being sent at a fixed interval. On-change subscriptions work by having the router compare the current state of the subscribed data path against its previous state; if no delta is detected, no update is generated, which conserves network and collector resources. On the ENCOR 350-401 exam, this concept tests your understanding of model-driven telemetry subscription types, and a common trap is confusing the on-change behavior with the suppress-repetition feature, which only reduces duplicate updates within periodic subscriptions. A useful memory tip is to think of on-change as “event-driven” versus periodic as “time-driven”—if the data doesn’t move, the message doesn’t leave.
350-401 Model-Driven Telemetry Practice Question
This 350-401 practice question tests your understanding of model-driven telemetry. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 configuring model-driven telemetry on a Cisco IOS-XE router to stream interface statistics to a collector using gRPC. The engineer wants to ensure that the telemetry data is sent only when there is a change in the interface counters, rather than at a fixed interval. Which configuration parameter should the engineer use to achieve this behavior?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Configure an on-change subscription
The correct answer is 'on-change' subscription because it triggers updates only when the monitored data changes, unlike periodic subscriptions that send data at fixed intervals. The other options are incorrect because 'periodic' sends data at a fixed interval, 'suppress-repetition' reduces duplicate updates in periodic subscriptions but does not enable on-change behavior, and 'sample-interval' is used for periodic subscriptions.
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.
✗
Use a periodic subscription with a sample-interval of 0
Why it's wrong here
A sample-interval of 0 is invalid; periodic subscriptions require a positive integer for the interval.
✓
Configure an on-change subscription
Why this is correct
An on-change subscription sends updates only when the monitored data changes, which matches the requirement.
Related concept
Read the scenario before looking for a memorised answer.
✗
Set the suppress-repetition flag in a periodic subscription
Why it's wrong here
The suppress-repetition flag reduces duplicate updates but still sends data at the periodic interval, not only on change.
✗
Use a dynamic subscription with a sample-interval of 1 second
Why it's wrong here
A dynamic subscription with a sample-interval sends data periodically, not only on change.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 350-401 question in full detail.
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.
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: Configure an on-change subscription — The correct answer is 'on-change' subscription because it triggers updates only when the monitored data changes, unlike periodic subscriptions that send data at fixed intervals. The other options are incorrect because 'periodic' sends data at a fixed interval, 'suppress-repetition' reduces duplicate updates in periodic subscriptions but does not enable on-change behavior, and 'sample-interval' is used for periodic subscriptions.
What should I do if I get this 350-401 question wrong?
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.
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 →
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. Examine the following telemetry configuration on a Cisco IOS-XE device:
telemetry ietf subscription 200
encoding encode-kvgpb
filter xpath /interfaces/interface[name='GigabitEthernet0/0/0']/state
stream yang-push
update-policy on-change
receiver ip address 192.168.1.100 50001 protocol grpc
Which statement is true about this configuration?
medium
✓ A.Data is pushed only when a change occurs in the state of GigabitEthernet0/0/0.
B.Data is pushed every 200 seconds to the collector.
C.The subscription uses JSON encoding.
D.The filter selects all interfaces, not just GigabitEthernet0/0/0.
Why A: This subscription uses on-change update policy, so data is pushed only when a change occurs in the specified subtree.
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Question Discussion
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