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Question 21.

Which technology enables applications to receive configuration changes through model-driven interfaces?

1. Telnet
2. NETCONF
3. TFTP
4. SNMPv1

Correct Answer: 2

Explanation:

NETCONF provides a structured mechanism for managing network configuration through standardized operations and data models. It commonly works with YANG models to represent configuration and operational data in a machine-readable form. Automation applications can use NETCONF to retrieve configuration, make controlled modifications, validate changes, and commit updates according to the capabilities of the target platform. This approach is different from traditional CLI automation because applications interact with structured data rather than parsing human-oriented command output. NETCONF is therefore an important protocol for model-driven network automation and programmatic infrastructure management.

Question 22.

Which YANG component describes the hierarchy of configuration data?

1. Module
2. Revision
3. Container
4. Namespace

Correct Answer: 4

Explanation:

A YANG module defines a data model and establishes the namespace associated with that model. The namespace uniquely identifies the vocabulary represented by the module and helps distinguish similarly named elements originating from different models. YANG models organize configuration and operational information through structures such as containers, lists, leaves, and groupings. Revision statements track model revisions, while containers organize related data within the model. Understanding namespaces is particularly important when automation applications process XML or JSON representations generated from YANG schemas because the same conceptual field names may exist in different modeling domains.

Question 23.

What does a YANG leaf typically represent?

1. A single data value
2. A collection of modules
3. A transport protocol
4. A validation server

Correct Answer: 1

Explanation:

A YANG leaf represents an individual data value within a data model. It can define information such as an interface description, administrative state, IP address, hostname, or numeric parameter. The model specifies the leaf’s type and may also define constraints governing acceptable values. Leaves can appear within containers or list structures and provide the actual fields that automation applications manipulate. Unlike a collection structure, a leaf represents one conceptual data element. Understanding the distinction between leaves, leaf-lists, containers, and lists helps engineers correctly navigate YANG-based models when developing model-driven automation workflows.

Question 24.

Which protocol provides a structured alternative to CLI-based configuration management?

1. FTP
2. ARP
3. NETCONF
4. ICMP

Correct Answer: 3

Explanation:

NETCONF provides a standardized, programmatic method for manipulating network configuration without depending on screen-oriented CLI interaction. It uses structured operations and can work with YANG-defined data models, allowing automation software to understand configuration elements more predictably. This reduces the need to construct device-specific command sequences and parse textual responses. FTP is primarily a file-transfer protocol, ARP resolves network-layer addresses to link-layer addresses, and ICMP supports network control and diagnostic messaging. NETCONF is therefore particularly relevant when implementing model-driven configuration workflows across supported network platforms.

Question 25.

Which YANG structure is designed to represent multiple instances identified by keys?

1. Leaf
2. Typedef
3. Grouping
4. List

Correct Answer: 4

Explanation:

A YANG list represents a collection of similar data nodes where each instance can be uniquely identified using one or more keys. For example, a model may represent multiple interfaces, VLANs, or routing entries as list instances. The key definition allows automation software to identify a particular entry when reading or modifying structured configuration. A leaf represents an individual value, a typedef defines reusable type information, and a grouping provides reusable schema components. Understanding YANG lists is essential when navigating hierarchical network data because many real-world configuration objects naturally occur as repeated entries.

Question 26.

Which NETCONF operation retrieves the running configuration from a device?

1. get-config
2. validate
3. commit
4. discard-changes

Correct Answer: 1

Explanation:

The NETCONF get-config operation retrieves configuration data from a specified configuration datastore. An automation application can use it to inspect the current running configuration or another supported datastore before making changes. This capability is useful for state comparison, configuration auditing, troubleshooting, and determining whether the intended configuration already exists. The validate operation checks proposed configuration, commit makes candidate changes active on systems supporting the relevant workflow, and discard-changes removes uncommitted candidate modifications. Using retrieval operations before configuration changes can help automation workflows make informed and controlled decisions.

Question 27.

What is the primary purpose of a YANG data model?

1. Generate encryption keys
2. Describe structured network data
3. Establish physical links
4. Allocate MAC addresses

Correct Answer: 2

Explanation:

YANG provides a formal language for describing structured data used in network management. Models define elements, relationships, data types, constraints, configuration characteristics, and operational information. Automation systems can use these definitions to understand how network information should be represented and manipulated. This model-driven approach provides greater consistency than relying entirely on free-form CLI output. YANG does not establish physical connections, allocate hardware addresses, or generate encryption keys. Its primary role is defining machine-readable data structures that management systems and automation applications can use to interact with network infrastructure.

Question 28.

Which NETCONF datastore normally represents the device’s active configuration?

1. Startup
2. Candidate
3. Running
4. Backup

Correct Answer: 3

Explanation:

The running datastore represents the configuration currently active on a network device. Automation applications can retrieve or manipulate running configuration when the platform and operation support it. The startup datastore generally represents configuration intended to be used when the device boots, while candidate is a separate editable configuration workspace on systems supporting the candidate capability. Backup is not a standard NETCONF datastore defined for this purpose. Understanding datastore roles is important when implementing configuration workflows because changes made to one datastore may not immediately become active or survive a device restart without the appropriate commit or save process.

Question 29.

Which HTTP response commonly indicates that authentication is required?

1. 401
2. 201
3. 204
4. 304

Correct Answer: 1

Explanation:

HTTP status code 401 indicates that the request lacks valid authentication credentials or that authentication is required before the requested resource can be accessed. Automation applications should recognize this response and handle authentication failures appropriately rather than repeatedly submitting the same unauthorized request. Status 201 commonly indicates successful resource creation, 204 indicates successful processing without a response body, and 304 indicates that a cached representation has not changed. Correctly interpreting status codes allows automation scripts to distinguish authentication problems from successful operations and other HTTP conditions.

Question 30.

Which automation concept uses reusable code for multiple device types?

1. Static addressing
2. Code reuse
3. Packet filtering
4. Port translation

Correct Answer: 2

Explanation:

Code reuse allows automation engineers to build common functions or modules that can be applied across multiple devices, platforms, or workflows. Instead of duplicating similar logic for every device type, reusable components can accept structured inputs and produce consistent results. This improves maintainability because changes to common behavior can be implemented in one location rather than across numerous scripts. Device-specific differences can be handled through variables, templates, data models, or abstraction layers. Static addressing, packet filtering, and port translation are networking concepts rather than software design techniques for maximizing reuse in automation applications.

Question 31.

Which Python module supports regular-expression pattern matching?

1. socket
2. json
3. re
4. pathlib

Correct Answer: 3

Explanation:

The Python re module provides functionality for working with regular expressions. Automation engineers can use regular expressions to identify patterns in strings, validate certain text formats, extract information, or transform data. This can be useful when processing logs, filenames, command output, or other text-based information that does not have a structured representation. The json module handles JSON serialization and parsing, socket provides low-level networking capabilities, and pathlib provides object-oriented filesystem path operations. Although structured APIs should generally be preferred when available, regular expressions remain useful when automation must process unstructured text.

Question 32.

Which approach allows configuration values to remain separate from automation logic?

1. Hardcoded commands
2. Embedded credentials
3. Static parsing
4. Externalized variables

Correct Answer: 4

Explanation:

Externalizing configuration values separates data from the code that performs automation tasks. Variables such as device addresses, interface names, credentials references, environment-specific parameters, or policy values can be stored separately and supplied to the automation workflow when it runs. This makes the same logic easier to reuse across development, testing, and production environments. It also reduces the need to modify source code whenever an environment-specific value changes. Hardcoding values directly into commands creates maintenance problems and can introduce security risks when sensitive information is embedded inside automation scripts.

Question 33.

Which Python library is commonly used to serialize and deserialize JSON data?

1. json
2. hashlib
3. time
4. logging

Correct Answer: 1

Explanation:

Python’s json module provides built-in functions for converting JSON data into Python objects and converting Python objects into JSON-formatted data. This capability is important in API-based network automation because many REST services exchange information using JSON. A script can deserialize an API response into dictionaries and lists, inspect required fields, modify values, and serialize a new request body when needed. The hashlib module supports hashing, time provides time-related functionality, and logging handles application logging. Proper JSON handling is therefore a fundamental skill for engineers working with REST-based network automation.

Question 34.

Which practice helps identify unintended changes introduced by an automation script?

1. Ignoring output
2. Configuration comparison
3. Removing backups
4. Skipping validation

Correct Answer: 2

Explanation:

Configuration comparison allows engineers to examine differences between an expected configuration and the configuration produced after an automation workflow runs. This can reveal unintended changes before they cause operational problems. Comparisons can be performed against a known-good baseline, a generated configuration, or another device with equivalent intended settings. Ignoring output and skipping validation remove useful safeguards, while removing backups reduces recovery options. In controlled automation environments, configuration comparison can therefore support change verification, troubleshooting, and auditing. It is especially valuable when scripts perform large-scale modifications across many network devices.

Question 35.

Which mechanism can provide asynchronous event notifications from network systems?

1. Webhook
2. Static route
3. Access list
4. VLAN trunk

Correct Answer: 1

Explanation:

A webhook allows a system to send an HTTP request to another application when a specified event occurs. This supports event-driven automation because the receiving application does not necessarily need to poll continuously for changes. For example, a management platform could notify an automation service when a particular network event, configuration change, or operational condition occurs. The receiving application can then validate the event and execute an appropriate workflow. Static routes, access lists, and VLAN trunks perform networking functions rather than providing general-purpose event notification mechanisms between software systems.

Question 36.

Which testing technique verifies individual automation functions independently?

1. Load testing
2. Smoke testing
3. Unit testing
4. Penetration testing

Correct Answer: 3

Explanation:

Unit testing focuses on verifying small, individual components of software independently from the rest of the application. In network automation, a unit test might validate a function that builds an API payload, transforms device data, calculates a configuration value, or interprets a response. Testing individual components makes defects easier to isolate and can provide faster feedback during development. Load testing evaluates behavior under workload, smoke testing provides a basic health check of a broader system, and penetration testing examines security weaknesses. Unit testing therefore plays an important role in developing dependable automation code.

Question 37.

Which source-control operation records changes in a Git repository?

1. clone
2. commit
3. fetch
4. checkout

Correct Answer: 2

Explanation:

A Git commit records a set of staged changes in the repository’s history. Each commit provides a snapshot that can be referenced later when reviewing development activity, investigating changes, or restoring earlier versions of automation code. The clone operation creates a local copy of a repository, fetch retrieves information from a remote repository without necessarily changing the working branch, and checkout is used for switching or restoring certain repository states depending on the workflow. Version control is valuable in network automation because it provides traceability and supports collaboration when multiple engineers develop and maintain automation projects.

Question 38.

Which automation design principle reduces dependence on a specific device CLI?

1. Vendor abstraction
2. Console attachment
3. Command duplication
4. Terminal emulation

Correct Answer: 1

Explanation:

Vendor abstraction reduces dependence on vendor-specific CLI syntax by representing automation tasks through common interfaces, models, libraries, or higher-level workflows. This allows an automation application to perform comparable operations across different platforms without embedding every vendor’s command syntax directly into the core logic. Abstraction can improve portability and maintainability, especially in heterogeneous environments. Console attachment and terminal emulation still depend on device interaction mechanisms, while command duplication increases maintenance effort. A well-designed abstraction layer can therefore make automation workflows easier to extend when infrastructure contains multiple hardware or software platforms.

Question 39.

Which feature allows an automation workflow to retry a temporarily failed operation?

1. Conditional retry logic
2. Static documentation
3. Interface shutdown
4. Address summarization

Correct Answer: 1

Explanation:

Conditional retry logic allows an automation program to attempt an operation again when a failure appears temporary or recoverable. Network APIs and devices can experience transient conditions such as short connection interruptions, temporary service unavailability, or rate-limit responses. A well-designed retry mechanism should use sensible limits and delays rather than continuously repeating failed requests. It can also distinguish retryable conditions from permanent errors, such as invalid credentials or malformed requests. This improves workflow resilience while avoiding uncontrolled request loops. Retry strategies are especially useful when automation must interact reliably with distributed network management systems.

Question 40.

Which practice provides a historical record of automation executions and outcomes?

1. Logging
2. Compression
3. Address translation
4. Packet capture

Correct Answer: 1

Explanation:

Logging records information about automation activity, including execution times, operations performed, errors encountered, device responses, and workflow outcomes. Detailed and appropriately structured logs can help engineers troubleshoot failures, verify changes, investigate unexpected behavior, and demonstrate what an automation process actually performed. Logging should avoid exposing sensitive credentials or tokens and should provide enough context to correlate related operations. Compression may reduce storage requirements, address translation modifies network addressing behavior, and packet capture records network traffic rather than serving as the primary application-level execution history. Effective logging is therefore a key component of reliable automation operations.