The answer is administratively down. When you send a PATCH request with a YANG interface payload that sets the enabled leaf to false, you are explicitly changing the administrative state of that interface to down, regardless of its previous configuration. In YANG data models like RFC 8343 or Cisco’s native models, the enabled leaf directly controls whether the interface is administratively up or down, and a PATCH operation applies only the fields you include, making it a precise way to toggle this state. On the Cisco DevNet Associate 200-901 exam, this tests your understanding of how RESTCONF and YANG model interface configuration, often contrasting PATCH (partial update) with PUT (full replacement). A common trap is confusing the operational state with the administrative state—remember that even if the interface has a physical link, setting enabled to false forces it administratively down. Memory tip: “PATCH the leaf, down the admin.”
200-901 Infrastructure and Automation Practice Question
This 200-901 practice question tests your understanding of infrastructure and automation. 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.
Refer to the exhibit. A Python script uses the YANG model to configure the interface. After applying this JSON payload via a PATCH request, what is the expected operational state of the interface?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Administratively down
The PATCH request applies the provided JSON payload, which sets the interface's 'enabled' leaf to 'false' (or equivalent YANG leaf for administrative state). In YANG models for interfaces (e.g., RFC 8343 or Cisco native models), setting 'enabled' to false places the interface in an administratively down state. The PATCH operation is valid for modifying interface configuration, and the payload explicitly changes the administrative state to down, overriding any previous configuration.
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.
✗
Error because PATCH is not allowed on interfaces
Why it's wrong here
PATCH is allowed.
✗
No change, remains as previously configured
Why it's wrong here
PATCH applies the payload.
✓
Administratively down
Why this is correct
enabled: false sets admin down.
Related concept
Read the scenario before looking for a memorised answer.
✗
Administratively up and protocol up
Why it's wrong here
Enabled false means administratively down.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between administrative state (controlled by the 'enabled' leaf) and operational state (which includes protocol status), and the trap here is that candidates may assume PATCH cannot modify administrative state or that the interface remains up if only a partial payload is sent.
Detailed technical explanation
How to think about this question
In YANG models like 'ietf-interfaces', the 'enabled' leaf (type boolean) directly controls the administrative state; setting it to false triggers the interface to be placed in a down state at Layer 1/2, regardless of previous configuration. The PATCH operation in RESTCONF (RFC 8040) performs a merge or replace of the target resource, so only the specified leafs are updated, leaving other interface parameters unchanged. This is commonly used in automation scripts to toggle interface states without affecting other attributes like IP addresses or MTU.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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.
Infrastructure and Automation — This question tests Infrastructure and Automation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Administratively down — The PATCH request applies the provided JSON payload, which sets the interface's 'enabled' leaf to 'false' (or equivalent YANG leaf for administrative state). In YANG models for interfaces (e.g., RFC 8343 or Cisco native models), setting 'enabled' to false places the interface in an administratively down state. The PATCH operation is valid for modifying interface configuration, and the payload explicitly changes the administrative state to down, overriding any previous configuration.
What should I do if I get this 200-901 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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