200-901 Infrastructure and Automation Practice Question
This 200-901 practice question tests your understanding of infrastructure and automation. 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.
Exhibit
Refer to the exhibit.
POST /api/v1/vlan HTTP/1.1
Host: 192.168.1.100
Authorization: Bearer <token>
Content-Type: application/json
{
"name": "Engineering",
"vlanId": 10
}
A Python script sends the above REST API request to a Cisco Catalyst 9000 switch running IOS XE. The response is a 400 Bad Request. Which field is most likely missing from the JSON payload?
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
interface
The REST API request is targeting the creation of a network interface on a Cisco Catalyst 9000 switch running IOS XE. The 400 Bad Request indicates a missing required field in the JSON payload. According to the Cisco IOS XE REST API documentation for the `/api/v1/interface` endpoint, the `interface` field (which specifies the interface name, e.g., 'GigabitEthernet1/0/1') is mandatory when creating a new interface. Without it, the API cannot determine which interface to configure, resulting in a 400 error.
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.
✗
vlanId
Why it's wrong here
The payload includes 'vlanId'.
✗
description
Why it's wrong here
Description is optional; its absence would not cause a 400.
✓
interface
Why this is correct
For VLAN creation, a mandatory 'interface' field (e.g., port membership) or 'vlanType' is required.
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.
✗
name
Why it's wrong here
The payload includes 'name'.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between the `interface` field (the actual interface identifier) and the `name` field (which is not used in this API), leading candidates to incorrectly choose `name` as the missing field.
Detailed technical explanation
How to think about this question
The Cisco IOS XE REST API uses a YANG data model (RFC 6020/7950) to define mandatory and optional fields for each resource. For the `/api/v1/interface` endpoint, the `interface` field is defined as a key leaf in the YANG model, meaning it is required for any POST operation. In a real-world automation scenario, omitting this field would cause the API to reject the request with a 400 status, as the server cannot uniquely identify the resource to create or modify.
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 help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
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: interface — The REST API request is targeting the creation of a network interface on a Cisco Catalyst 9000 switch running IOS XE. The 400 Bad Request indicates a missing required field in the JSON payload. According to the Cisco IOS XE REST API documentation for the `/api/v1/interface` endpoint, the `interface` field (which specifies the interface name, e.g., 'GigabitEthernet1/0/1') is mandatory when creating a new interface. Without it, the API cannot determine which interface to configure, resulting in a 400 error.
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.
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.
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 →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 200-901 practice question is part of Courseiva's free Cisco 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 200-901 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.