CCNP Automation Practice Question
A network automation team is using YANG models with NETCONF to configure a Cisco IOS XE device. They want to change the description of a loopback interface. The engineer writes an <edit-config> RPC with the 'operation' attribute set to 'merge' on the <description> leaf. The RPC is accepted, but the description is not changed. The engineer verifies that the YANG path is correct and that the interface exists. What is the most likely reason the description was not updated?
⚠ Common exam trap
The trap here is assuming that a successful <edit-config> RPC immediately changes the running configuration, forgetting that candidate datastores require an explicit commit.
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 <edit-config> RPC was sent to the 'candidate' datastore, but a <commit> operation was not performed.
When using NETCONF with a candidate datastore, <edit-config> modifies the candidate configuration but does not affect the running configuration until a <commit> RPC is executed. The RPC being accepted without error indicates the edit was valid but not applied. The engineer must send a <commit> to activate the change. Other options like namespace or operation type would typically produce errors, not silent acceptance.
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 <edit-config> RPC was sent to the 'candidate' datastore, but a <commit> operation was not performed.
Why this is correct
If the device is configured to use the candidate datastore, changes made via <edit-config> are not active until a <commit> RPC is issued. The RPC would be accepted without error, but the running configuration remains unchanged. This is a common oversight when using NETCONF with candidate datastores. Issuing a <commit> applies the changes.
- ✗
The description leaf is read-only in the YANG model and cannot be modified via NETCONF.
Why it's wrong here
The description leaf for an interface is typically read-write in standard YANG models like ietf-interfaces. If it were read-only, the device would return an error indicating the operation is not allowed. Since the RPC was accepted, the leaf is likely writable. The issue is not permissions but the need to commit changes to the candidate datastore.
- ✗
The 'merge' operation requires the parent container to be specified with a namespace, which was omitted.
Why it's wrong here
YANG namespaces are required in NETCONF XML payloads, but if omitted, the device would typically return an error indicating unknown namespace or element. Since the RPC was accepted without error, the namespace was likely correct. The issue is more about operation semantics than namespace. Omitting namespace usually causes a parse error, not silent failure.
- ✗
The 'operation' attribute must be set to 'replace' instead of 'merge' to change a leaf value.
Why it's wrong here
The 'merge' operation is designed to update or create a leaf if it does not exist. It should change the description if the leaf is present. Using 'replace' would also work but is not required. The fact that the RPC was accepted but no change occurred suggests a different issue, such as the leaf being part of a different data model or a commit not being applied.
About these practice questions
One of 1,923 original 350-401 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 350-401 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 350-401 exam.