Question 1

Which two programming languages have a NETCONF library supported by Juniper Networks? (Choose two.)

Accepted Answer

B, C

Explanation: Juniper Networks officially supports and maintains NETCONF client libraries for both Python and Go, facilitating automated interaction with devices running the Junos OS. The Python library, known as Junos PyEZ (junos-eznc), is a micro-framework that simplifies the management and automation of Junos devices. Similarly, Juniper provides go-netconf, a NETCONF client library for the Go programming language. These libraries enable developers to programmatically execute RPCs, manage configurations, and retrieve operational state from network devices using the NETCONF protocol.

Question 2

A REST API client uses which two HTTP methods to execute RPC requests on the server? (Choose two.)

Accepted Answer

A, C

Explanation: The Junos OS REST API provides a framework for remotely executing Remote Procedure Calls (RPCs) on a device. To invoke an RPC, a client application sends an HTTP request to the specific RPC resource endpoint. The API supports two primary HTTP methods for this purpose: GET and POST. The GET method is typically used for simple, idempotent RPCs where the command can be encoded directly in the URL. The POST method is used for all RPCs, including those that require data to be sent in the request body, such as configuration changes or more complex operational commands.

Question 3

Which statement is valid regarding YAML and JSON?

Accepted Answer

D

Explanation: Both YAML and JSON are case-sensitive data serialization formats. In both, keys are treated as strings, and string comparisons are performed in a case-sensitive manner. This means that a key named interface is distinct from a key named Interface. This characteristic is fundamental to how parsers interpret the data structure and access specific key-value pairs.

Question 4

Which two statements about the REST API are correct? (Choose two.)

Accepted Answer

B, C

Explanation: A fundamental architectural constraint of REST (Representational State Transfer) is statelessness. This means the server does not maintain any client session state between requests. Each request from a client must contain all the information necessary for the server to understand and process it, making the application itself stateless. Because the server does not store session information, the responsibility for maintaining the state of a session (e.g., authentication tokens, user context) is delegated to the client. The client must include this state information with every subsequent request to the server.

Question 5

Which development model is the classic approach to software development?

Accepted Answer

A

Explanation: The Waterfall model is considered the classic and traditional approach to the software development life cycle (SDLC). It is a linear-sequential model where progress flows in one direction, downwards through distinct phases: requirements, design, implementation, verification, and maintenance. Each phase must be fully completed before the next can begin. This rigid, structured methodology was one of the earliest formalized models, making it the foundational or "classic" approach, in contrast to more modern, flexible, and iterative methodologies.

Question 6

Which statement is correct about DevOps?

Accepted Answer

C

Explanation: DevOps is a cultural philosophy and a set of practices that integrates software development (Dev) and IT operations (Ops). The primary goal is to shorten the systems development life cycle and provide continuous delivery with high software quality. This is achieved by breaking down the traditional silos between development, operations, quality assurance, and other teams, fostering a culture of collaboration and shared responsibility. By uniting these teams, DevOps improves communication and streamlines workflows, leading to faster and more reliable project outcomes.

Question 7

Exhibit. https://kxbjsyuhceggsyvxdkof.supabase.co/storage/v1/object/public/file-images/Juniper_JN0-223/page_62_img_1.jpg Referring to the exhibit, which XML XPath expression will only show the IP address XML elements?

Accepted Answer

A

Explanation: The XPath expression //address/name correctly selects the target elements based on the provided XML structure. The double forward slash // is a recursive descendant selector, meaning it finds all elements anywhere in the document. The subsequent /name then selects the child element within each located element. This path accurately navigates the hierarchy shown in the exhibit to isolate the elements (host1 and host2). Although the question asks for "IP address XML elements," the provided options only target the element, indicating a likely typo in the question's text. Option A is the most specific and accurate choice for selecting the elements as structured.

Question 8

Exhibit. https://kxbjsyuhceggsyvxdkof.supabase.co/storage/v1/object/public/file-images/Juniper_JN0-223/page_56_img_1.jpg Referring to the exhibit, which two statements about the script are correct? (Choose two.)

Accepted Answer

A, D

Explanation: The script issues the RPC get-configuration with the option format='json', so the data returned from the device is JSON, not XML. It then iterates over the JSON list interfaces.interface[] and prints only the value of the field name for each entry. No additional interface attributes are displayed. Hence the script (1) retrieves the interface configuration in JSON, and (2) prints the name of every configured interface.

Question 9

Which two statements are valid regarding Junos automation? (Choose two.)

Accepted Answer

C, D

Explanation: The Junos operating system utilizes distinct daemons to manage different automation and programmability interfaces. The Management Daemon (mgd) is the primary process responsible for user interface interactions, including NETCONF sessions. As NETCONF is the standard protocol for the Junos XML API, mgd handles all XML API requests. Conversely, the Junos Extension Toolkit (JET) is a newer framework that uses a separate process. The JET Service Process (jsd) runs on the Routing Engine and is specifically designed to manage all API requests and event notifications for JET applications, providing a dedicated interface for high-frequency programmatic interaction.

Question 10

Which Junos API supports direct modification of the Ephemeral database?

Accepted Answer

A

Explanation: The Juniper Extension Toolkit (JET) API is specifically designed for high-performance, programmatic interaction with Junos devices. It utilizes gRPC services to enable applications to directly and rapidly modify the ephemeral configuration database. This database is an alternate, non-validating datastore intended for fast configuration updates from automation tools and SDN controllers, bypassing the standard commit model for speed. The other listed APIs do not provide this direct modification capability for the ephemeral instance.

Question 11

What is the correct sequence for Python script execution?

Accepted Answer

B

Explanation: The standard Python (CPython) execution model follows a specific sequence. First, the Python interpreter reads and parses the source code (.py file). This initial stage can be broadly termed "interpretation." During this phase, the interpreter translates the human-readable source code into an intermediate, low-level representation called "bytecode." This bytecode is then passed to the Python Virtual Machine (PVM), which executes it at runtime. This hybrid approach combines compilation to an intermediate form with interpretation of that form, providing both portability and performance benefits.

Question 12

Which two programming languages are used for Junos on-box scripting? (Choose two.)

Accepted Answer

C, D

Explanation: Junos OS provides a native, on-box scripting framework to automate operational and configuration tasks. The two primary languages supported for this framework are Extensible Stylesheet Language Transformations (XSLT) and Style Sheet Language Alternative Syntax (SLAX). XSLT is a W3C standard for transforming XML data, which is the native format for the Junos OS configuration and operational state. SLAX is a Juniper-developed language that provides a simpler, more intuitive syntax for writing automation scripts while still being processed as XSLT. These languages are used to create op, commit, event, and SNMP scripts that run directly on the device.

Question 13

Which type of on-box automation script is designed to run every time a user executes a configuration change?

Accepted Answer

C

Explanation: Commit scripts are a type of on-box automation script in Junos OS that are specifically designed to be executed during the commit process. When a user issues the commit command to apply a candidate configuration, the commit script is invoked. These scripts can be used to enforce custom configuration rules, validate the configuration against specific policies, or automatically generate additional configuration statements based on the changes being committed.

Question 14

You want to use a Python package or module. In this scenario, which statement would accomplish this task?

Accepted Answer

D

Explanation: In Python, the import statement is the standard and required method for loading and using external code contained within a module or a package. When a module is imported, Python executes the code in the module file and makes its functions, classes, and variables available in the current program's namespace. This allows for code reuse and modular program design, which are fundamental principles in software development and network automation scripts relevant to the JN0-223 exam. For example, import jnpr.junos would be used to access the Junos PyEZ library.

Question 15

Which data construct is used to guarantee that element names and data values remain unique in an XML document?

Accepted Answer

C

Explanation: XML namespaces are the standard mechanism used to prevent naming conflicts in XML documents. By associating a prefix with a unique Uniform Resource Identifier (URI), a namespace qualifies element and attribute names. This ensures that when XML documents from different sources or vocabularies are combined, elements that share the same local name (e.g., ) but have different meanings can be uniquely identified and processed without ambiguity (e.g., and ). This qualification by a unique URI is the construct that guarantees element names remain unique.

Free Juniper JN0-223 Actual Exam Questions