JNCIA-DevOps NETCONF And XML API Practice Question
During troubleshooting of a Python script using the ncclient library to interact with a Junos device, an automation engineer observes a 'rpc-error' response containing an error-tag of 'operation-failed'. Upon examining the Junos system logs, it is discovered that the candidate configuration had syntax errors introduced by an uncommitted previous session. Which NETCONF capability negotiation mechanism ensures that the client is aware of the exact XML schema constraints before sending the RPC?
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
✓
NETCONF capability URIs exchanged during the initial hello message exchange.
NETCONF hello messages exchange capabilities, which include URLs pointing to XML namespaces and data models such as YANG modules or Junos specific DTDs/XSDs.
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 <get-schema> RPC operation defined in RFC 6020.
Why it's wrong here
While <get-schema> retrieves specific YANG modules, it is executed after the hello message exchange and is not the primary capability negotiation mechanism.
- ✗
The automatic download of Junos PyEZ schema definitions during the SSH handshake phase.
Why it's wrong here
Junos PyEZ operates on top of NETCONF but does not fetch schemas during the SSH handshake.
- ✓
NETCONF capability URIs exchanged during the initial hello message exchange.
Why this is correct
Clients and servers advertise supported models and schema namespaces via capability URIs in the initial hello messages.
- ✗
The automated execution of a pre-flight XML validation check via the <validate> RPC.
Why it's wrong here
<validate> checks configuration correctness but does not negotiate schema capabilities during session establishment.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Juniper Networks exam blueprint
This JNCIA-DevOps practice question is part of Courseiva's free Juniper Networks 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 JNCIA-DevOps exam.