Cisco 200-901 - DevNet Associate (DEVASC)

Edge computing solutions are utilized where low latency is needed. Edge computing involves processing data closer to where it is generated (at the edge of the network), which reduces the latency compared to sending data to a centralized data center for processing.

Low Latency Needs: Edge computing is designed to provide real-time data processing and decision-making by reducing the distance data has to travel. This is crucial for applications requiring immediate data processing, such as IoT devices, autonomous vehicles, and real-time analytics.

References: Cisco DevNet Associate Certification Guide, Chapter on IoT and Edge Computing.

Test-Driven Development (TDD) is a software development approach where tests are written before writing the actual code. The steps involved in TDD are:

Write a test for the new functionality.

Run the test and see it fail (because the functionality is not yet implemented).

Write the minimum code necessary to make the test pass.

Refactor the code while keeping the test passing.

Option B is the correct answer because refactoring code while it is covered by existing tests is a key aspect of TDD. The existing tests ensure that the functionality remains correct even after refactoring.

References:

Cisco DevNet Associate Exam Topics: Software Development and Design (understanding TDD methodology)

"Test-Driven Development by Example" by Kent Beck (standard reference on TDD)

The Bash script shown performs the following actions:

It reads a directory name into the variable ndir.

It enters a loop that continues as long as the directory specified by ndir exists (-d "$ndir" checks if a directory exists).

Inside the loop, it changes the current directory to ndir.

Once the loop exits (when a directory with the name ndir no longer exists), it creates a new directory with the name stored in ndir.

Thus, the script ensures that it continues to navigate into directories with the given name until it finds one that does not exist, and then creates it.

The YANG model provided in the exhibit defines the structure for interface information, including fields for name, admin-status, if-index, and statistics. The correct XML snippet must match this structure and use the appropriate namespaces and field names as defined in the YANG model.

Namespace: The XML must include the namespace urn:ietf:params:xml:ns:yang:ietf-interfaces and the prefix if.

Interface Information: The XML must include elements for name, admin-status, if-index, and statistics as defined in the YANG model.

Field Names and Values: The field names must match the YANG model (admin-status, if-index, in-octets, in-unicast-pkts).

Option D is the correct XML snippet because it accurately conforms to the YANG model. It includes the required elements and correctly uses the namespace and field names:

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NETCONF (Network Configuration Protocol) is a standard used for network device configuration, and it utilizes YANG (Yet Another Next Generation) as a data modeling language. Cisco IOS XE and Cisco NX-OS support NETCONF and YANG to automate the configuration and management of network devices across a network. YANG defines the data models, while NETCONF provides the protocol to manipulate these models.

References:

Cisco DevNet Documentation - NETCONF and YANG

IETF RFC 6241 - NETCONF Protocol

IETF RFC 6020 - YANG Data Modeling Language

A 401 error indicates unauthorized access. To fix this, the script needs to include the appropriate authorization token in the request headers.

Authorization Header: The Authorization header with a Bearer token is commonly used for OAuth 2.0 authorization.

Bearer Token: This token is used to authenticate API requests securely.

Option A is correct as adding the Authorization header with the Bearer token is the proper way to authenticate the request and resolve the 401 error.

GIT PUSH

To start a CI/CD pipeline and run automated tests after modifying the code in a cloned repository, the appropriate command is git push. When a developer pushes the changes to the remote repository, it triggers the CI/CD pipeline configured in the repository. Here are the steps:

Clone the repository from GitLab.

Make the necessary code modifications.

Use git commit to commit the changes locally.

Use git push to push the committed changes to the remote repository.

Pushing the changes to the remote repository initiates the CI/CD pipeline, which typically includes steps like building the application, running tests, and deploying the application if tests pass.

References:

Cisco DevNet Associate Certification Guide

GitLab CI/CD Documentation

The first stage of a CI/CD (Continuous Integration/Continuous Deployment) pipeline typically involves developers committing and pushing code into a version control system (VCS) such as Git. This stage sets the foundation for subsequent automated processes.

Version Control System (VCS): A VCS allows multiple developers to work on code simultaneously, track changes, and manage versions.

Initial Commit: The act of committing code means saving changes to the local repository.

Push to Repository: Pushing code sends the committed changes to a remote repository, making them available for the CI/CD pipeline to trigger automated processes such as building and testing.

References:

Continuous Integration Fundamentals: CI/CD Overview

Infrastructure as Code (IaC) principles relate to the service provisioning stage of development. IaC involves managing and provisioning computing infrastructure through machine-readable definition files, rather than through physical hardware configuration or interactive configuration tools.

Service Provisioning: IaC allows for the automated deployment and management of infrastructure resources. This includes servers, databases, networks, and other components necessary for running applications and services.

Automation and Consistency: IaC ensures that the infrastructure is provisioned consistently and repeatably, reducing the chances of human error and increasing efficiency.

References:

Cisco DevNet Associate Certification Guide

Infrastructure as Code (IaC) Principles