CCNA AI and Network Operations Practice Question
An engineer receives API output that starts with curly braces and contains name-value pairs. Which data format is being used?
⚠ Common exam trap
A frequent exam trap is mistaking YANG for the data format when seeing curly braces and name-value pairs. YANG is a modeling language that defines the structure and constraints of network data but does not represent the actual data payload. Candidates might also confuse Syslog or SMTP with JSON due to their familiarity with network protocols, but these protocols do not use JSON’s syntax. This confusion leads to selecting incorrect answers, especially under time pressure. Recognizing that JSON is the payload format commonly used in Cisco APIs helps avoid this mistake and correctly interpret automation output.
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
✓
JSON
JSON represents data as objects and arrays using braces, brackets, and name-value pairs. It is the most common format you will see in modern network APIs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
YANG
Why it's wrong here
YANG (Yet Another Next Generation) is a data modeling language used to define the configuration and state data trees for NETCONF and RESTCONF, not a serialization or payload format. A YANG module describes schema using containers, leafs, and lists, but when data is transmitted, it is encoded in XML or JSON — not as raw YANG itself. Therefore, the output received by the engineer cannot literally be YANG.
When this WOULD be correct
When asked which data modeling language is used to define the structure of NETCONF or RESTCONF configuration data, YANG would be the correct answer.
- ✓
JSON
Why this is correct
A payload that begins with a curly brace is the signature of a JSON object. JSON (JavaScript Object Notation) is a lightweight, language-independent data-interchange format in which data is organized as key-value pairs within braces. REST APIs commonly return JSON, and the very first character being '{' confirms the representation is a JSON document rather than a flat text or structured binary format.
- ✗
Syslog
Why it's wrong here
Syslog is a logging standard that defines both a message format and a transport mechanism (UDP/TCP port 514). Its messages typically begin with a priority value in angle brackets, followed by a timestamp, hostname, and text description — never a curly brace. Even modern structured syslog versions use JSON only when explicitly configured, but the legacy and most common syslog output is plain text, so this option does not match the described output.
When this WOULD be correct
A question asking which protocol is used for centralized logging of network device events, where the answer options include Syslog, SNMP, and NetFlow.
- ✗
SMTP
Why it's wrong here
SMTP (Simple Mail Transfer Protocol) is an application-layer protocol for email transmission, operating with ASCII text commands such as HELO, MAIL FROM, and RCPT TO. Its exchanges are line-oriented and do not use curly-brace delimiters or structured object syntax. Since the problem states the output starts with a curly brace, SMTP is an implausible format.
When this WOULD be correct
A question asks which protocol is used to send email messages between mail servers. In that context, SMTP would be the correct answer.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓JSONCorrect answer▾
Why this is correct
A payload that begins with a curly brace is the signature of a JSON object. JSON (JavaScript Object Notation) is a lightweight, language-independent data-interchange format in which data is organized as key-value pairs within braces. REST APIs commonly return JSON, and the very first character being '{' confirms the representation is a JSON document rather than a flat text or structured binary format.
✗YANGWrong answer — click to see why▾
Why this is wrong here
YANG is a data modeling language used to define data structures for network configuration and state, not a data serialization format. The description of curly braces and name-value pairs matches JSON, not YANG.
★ When this WOULD be the correct answer
When asked which data modeling language is used to define the structure of NETCONF or RESTCONF configuration data, YANG would be the correct answer.
Why candidates choose this
Candidates may confuse YANG with JSON because YANG models can be serialized in JSON format, leading them to think YANG itself is a data format.
✗SyslogWrong answer — click to see why▾
Why this is wrong here
Syslog is a protocol for message logging, not a data format. It does not use curly braces or name-value pairs; its messages are plain text with a specific header format.
★ When this WOULD be the correct answer
A question asking which protocol is used for centralized logging of network device events, where the answer options include Syslog, SNMP, and NetFlow.
Why candidates choose this
Candidates may confuse Syslog with JSON because both can be used in API contexts (e.g., sending logs as JSON), but Syslog itself is not a data format.
✗SMTPWrong answer — click to see why▾
Why this is wrong here
SMTP is a protocol for email transmission, not a data format. The question describes a format with curly braces and name-value pairs, which is characteristic of JSON, not SMTP.
★ When this WOULD be the correct answer
A question asks which protocol is used to send email messages between mail servers. In that context, SMTP would be the correct answer.
Why candidates choose this
Candidates may confuse data formats with protocols, or they might think SMTP can carry structured data like JSON, but the question specifically asks about the data format itself.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
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Agentic AI in Network Operations
Key term
JSON
JSON is a lightweight, text-based format for storing and exchanging data that is easy for humans to read and write and easy for machines to parse and generate.
Key term
API
An API is a set of rules that allows software applications to communicate and exchange data with each other.
About these practice questions
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 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 200-301 exam.