200-901 DevNet Associate (DEVASC) Questions and Answers

1 – B, 2 – E, 3 – C, 4 – D, 5 – A

A platform that runs directly using a hypervisor is referred to as a virtual machine (VM). A hypervisor, also known as a virtual machine monitor (VMM), is software that creates and runs VMs. It allows multiple VMs to share the hardware resources of a physical host, providing isolation and resource management for each VM.

Statement B: One of the routers has two connected serial interfaces.

This statement is true if the diagram indicates that a router has two serial interfaces. In network diagrams, routers often have multiple interfaces to connect different segments or other routers, particularly for WAN connections.

Statement E: The subnet address of PC-B has 18 bits dedicated to the network portion.

If PC-B's subnet is represented by an address such as 192.168.x.x/18, then 18 bits are used for the network portion, leaving 14 bits for host addresses. This aligns with standard subnetting practices where a /18 subnet mask means the first 18 bits define the network, and the remaining bits define host addresses.

For example, a subnet mask of 255.255.192.0 corresponds to /18 in CIDR notation, indicating that the first 18 bits are for the network portion.

Incorrect Statements:

Statement A: PC-A and PC-B are in the same subnet.

This statement can be evaluated based on the IP addresses and subnet masks provided for PC-A and PC-B. If they share the same network portion of their addresses and subnet masks, then they are in the same subnet. However, without explicit addresses, this cannot be verified.

Statement C: The subnet of PC-C can contain 256 hosts.

For a subnet to contain 256 hosts, it would need a /24 subnet mask (255.255.255.0), which provides 256 IP addresses (254 usable for hosts). The subnet mask should be examined to determine the validity of this statement.

Statement D: R1 and R3 are in the same subnet.

This depends on the IP addresses and subnet masks assigned to the interfaces on R1 and R3. If they are within the same network range, then they would be in the same subnet.

Since the network diagram is not provided, the verification is based on common networking principles and standard practices in subnetting. For detailed and accurate confirmation, the exact IP addresses, subnet masks, and interface connections need to be reviewed.

Version control software offers numerous benefits to development teams. Key advantages include:

Comparisons between revisions of source code files: Version control allows developers to compare different versions of source code files, track changes, and identify what modifications were made and by whom. This is essential for debugging and maintaining code quality.

Access to current code and history for new team members: New team members can quickly get up to speed by accessing the current version of the code and the entire history of changes. This transparency facilitates onboarding and improves collaboration among team members.

To extract the value "172.16.0.11" from the given JSON data, you need to navigate through the JSON structure using the correct keys and indices. The JSON structure provided is as follows:

"items": [{

"kind": "object#NetworkObj",

"selfLink": "https://10.201.230.5/api/objects/networkobjects/db01 ",

"name": "db01",

"host": {

"kind": "IPv4Address",

"value": "172.16.0.11"

},

"objectId": "db01"

}]

}

Access the 'items' key: This gives you a list containing one object.

Access the first object in the 'items' list: Using the index [0].

Access the 'host' key: This contains the 'kind' and 'value' keys.

Access the 'value' key within the 'host' object: This gives you the required value "172.16.0.11".

Thus, the correct way to access the value "172.16.0.11" is data['items'][0]['host']['value'].

References:

JSON Parsing in Python: Python JSON Module

Cisco DevNet Documentation: DevNet JSON Handling

1 – A, 2 – C, 3 – B

The script provided in the exhibit shows the following steps:

It configures a loopback interface (interface loopback 5; no shut).

It retrieves the interface details and parses the JSON output to list interfaces that are up.

Therefore, the correct answers are: A. Configure interface loopback 5. C. Show only the interfaces in the up status.

 Asynchronous API calls are non-blocking, meaning the application can continue processing other tasks while waiting for the API call to complete. This helps improve the efficiency and responsiveness of the application. Typically, a callback function is used to handle the response once the API call completes.

Option B is correct because asynchronous API calls do not block the code; they allow the application to perform other operations concurrently.

Option E is correct because a callback function is usually implemented to handle the response of an asynchronous API call once it completes.

References:

Cisco DevNet Associate Exam Topics: APIs and Automation (understanding synchronous and asynchronous API calls)

Asynchronous Programming Documentation (explains how asynchronous calls work and the use of callbacks)

1 - d, 2 - f, 3 - b, 4 - h, 5 - i, 6 – j, 7 - g, 8 - a, 9 - c, 10 - e

1 – C, 2 – D, 3 – B, 4 - A

Injection attacks occur when untrusted data is sent to an interpreter as part of a command or query. The attacker's hostile data can trick the interpreter into executing unintended commands or accessing data without proper authorization. Common types of injection attacks include SQL injection, command injection, and LDAP injection. These types of attacks exploit vulnerabilities in how an application processes input data, allowing attackers to inject malicious commands or queries into the system.

A version control system offers several advantages:

Branching and Merging: Developers can work on features, bug fixes, or experiments in isolation (branches) without affecting the main codebase. Once the work is completed, it can be merged back into the main branch, facilitating organized and controlled development workflows.

Infrastructure as Code (IaC) involves managing and provisioning computing infrastructure through machine-readable definition files, rather than physical hardware configuration or interactive configuration tools.

Principles of IaC:

Reusability: Complete complex systems must be built from reusable infrastructure definitions. This means infrastructure components should be modular and reusable across different environments and applications.

Consistency: Environments must be provisioned consistently using the same inputs. This ensures that every environment is set up exactly the same way, reducing the risk of errors and discrepancies.

Other Principles:

Declarative Configuration: Using a high-level language to define what the infrastructure should look like rather than how to achieve it.

Version Control: Infrastructure definitions are stored in version control systems, making changes trackable and reversible.

Incorrect Options:

C. Redeployments cause varying environment definitions: This is against IaC principles as it emphasizes consistency.

D. Service overlap is encouraged to cater for unique environment needs: This could lead to complex and unmanageable configurations.

E. Components are coupled, and definitions must be deployed for the environment to function: IaC promotes decoupled, modular components.

References:

Infrastructure as Code: IaC Principles

There are two primary types of NAT (Network Address Translation) used in networking:

Static NAT: Maps a single private IP address to a single public IP address. This type of NAT is useful when you want a specific internal device (like a server) to be accessible from the internet using a consistent public IP address.

Dynamic NAT: Maps a private IP address to a public IP address from a pool of available public IP addresses. This type of NAT is used when you want internal devices to access the internet but do not require a consistent public IP address for each internal device.

Other types mentioned (Normal NAT, Multicast NAT, Router NAT) are not standard terms or widely recognized types of NAT.

Generating log bundles is a resource-intensive task that can cause high CPU utilization on the Cisco DNA Center. When the CPU spikes, it can affect the performance of other critical tasks, such as forwarding voice IP packets, leading to delays and poor voice quality. This is especially noticeable during business hours when network utilization is high, and voice traffic is sensitive to latency and jitter. More details can be found in Cisco DNA Center documentation on Managing Logs and System Performance.

Cisco IOS XE supports model-driven programmability using protocols such as gNMI (gRPC Network Management Interface). gNMI is a protocol that provides a way to manage and configure network devices using a standardized approach to data models and APIs.

Model-Driven Telemetry: gNMI is used for streaming telemetry data from network devices.

Configuration Management: It allows for the configuration of network devices using standardized YANG models.

The HTTP status code 200 indicates successful execution of a request.

Status Code 200:

Meaning: OK - The request has succeeded. The meaning of the success depends on the HTTP method:

GET: The resource has been fetched and is transmitted in the message body.

HEAD: The headers are in the message body.

POST: The resource describing the result of the action is transmitted in the message body.

TRACE: The message body contains the request message as received by the server.

Comparison with Other Codes:

404 - Not Found: The server can’t find the requested resource.

405 - Method Not Allowed: The request method is known by the server but is not supported by the target resource.

500 - Internal Server Error: The server encountered an unexpected condition that prevented it from fulfilling the request.

Thus, the status code 200 indicates that the request was successful.

References:

HTTP Status Codes: MDN Web Docs

Cisco DNA Center is a network management and command center for enterprise networks, providing network controller-level management features. It offers capabilities such as automation, assurance, fabric provisioning, and policy-based segmentation, making it a comprehensive solution for managing and optimizing network performance and operations. Cisco DNA Center is part of the broader Cisco Digital Network Architecture (Cisco DNA), designed to facilitate the efficient and automated management of networks. More information can be found on the Cisco DNA Center product page.

Top of Form

Bottom of Form

A routing table contains critical information used by routers to determine the best path for forwarding packets. The essential details included in a routing table are:

Destination network: The IP address of the destination network.

Next hop: The IP address of the next hop router or the outgoing interface to reach the destination network.

Metric: The cost associated with the path to the destination network, used to select the best route.

Route type: The type of route (e.g., directly connected, static, dynamic).

When a developer encounters many lines of code doing repetitive tasks, refactoring the code to use functions is a standard practice. This reduces code duplication and enhances readability and maintainability. Functions encapsulate repetitive logic, making the code cleaner and more organized.

Option A correctly creates a handle instance using the UcsHandle class from the UCS SDK in Python. The correct instantiation requires providing the IP address, username, password, port number, and secure connection parameters as per the documented API.

The correct code snippet is:

from ucsmsdk.ucshandle import UcsHandle

handle = UcsHandle("10.1.2.254", "admin", "password", port="443", secure=True)

This snippet matches the API documentation requirements:

ip: The IP or hostname of the UCS Server.

username: The username as configured on the UCS Server.

password: The password as configured on the UCS Server.

port: The port number to be used during the connection.

secure: True for a secure connection.

References:

UCS Python SDK Documentation (provides details on how to use UcsHandle)

Cisco DevNet Associate Exam Topics: Infrastructure and Automation (understanding how to use APIs and SDKs for automation)

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The YANG module shown in the exhibit is for interface management. It augments the ietf-interfaces module and defines parameters specific to Ethernet interfaces, such as auto-negotiation, duplex mode, and speed. This module is designed to manage the configuration and operational state of Ethernet interfaces. References for YANG modules can be found in the IETF YANG Data Model for Interface Management.

A 401 Unauthorized error indicates that the request has not been applied because it lacks valid authentication credentials for the target resource. To resolve this error when making an HTTP GET request to retrieve data using RESTCONF on a CSR 1000V, you need to ensure that the correct authentication credentials (username and password) are provided.

This Python script uses the Cisco DNA Center API to retrieve a list of network devices. The steps are:

Import the required libraries: requests for making HTTP requests and json for handling JSON data.

Define the API endpoint URL for retrieving network devices from Cisco DNA Center.

Set up the request headers, including the content type and the authentication token (X-Auth-Token).

Send a GET request to the API endpoint.

Check the response status code to ensure the request was successful.

If successful, parse and print the JSON response containing the list of network devices. Otherwise, print an error message.

Grpc == http/2 , netconfig == ssh , restconfig == https

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

Write a test before writing code (B): Developers write tests for a new function or feature before implementing it. This ensures that the tests define what the code is supposed to do.

Enable code refactoring (A): Because tests are written first, TDD supports continuous refactoring of the code. Developers can confidently improve and clean up code, knowing that existing functionality is verified by the tests.

 Understand the JSON Structure: The JSON data given in the exhibit consists of an array of objects. Each object has a type and an items key. The items key contains an array of objects, each with a color and another items key, which is an array of strings representing items of that color.

 Analyze the Python Code: The Python code provided is:

print(filter(lambda l: l['type'] == 'fruit', vegetables)[0]['items'][0]['items'][0])

Break Down the Code:

filter(lambda l: l['type'] == 'fruit', vegetables): This line filters the JSON array vegetables to include only objects where the type is 'fruit'.

filter(...)[0]: After filtering, this selects the first object in the filtered list, which is the fruit object.

['items'][0]: This accesses the first item in the items array of the fruit object. In this case, it refers to the object where color is "green".

['items'][0]: This accesses the first item in the items array of the green object, which is "kiwi".

Evaluate the Code:

The first object of type fruit in the JSON is found.

The first item in the items array for fruit with the color green is selected.

The first item in this nested items array is "kiwi".

Therefore, the output of the given Python command is "Kiwi".

References:

Python documentation on filter: Python Docs - Filter

JSON structure understanding from DevNet Associate study materials on API interactions and data parsing.

Network programmability allows for automated, scalable, and replicable network provisioning and management. This reduces the need for manual configuration, minimizes human errors, and enables the implementation of consistent network policies across multiple devices and environments. By leveraging APIs and automation tools, network operations become more efficient and can easily adapt to changes in the network.

The function my_func() returns True when it executes normally. To test this function using Python's unittest framework, the correct assertion to use is assertTrue. This method tests if the given expression evaluates to True.

Option A (self.assertTrue(my_func())): This assertion checks if my_func() returns True.

Option B (self.assertRaises(my_func())): This is used to check if a specific exception is raised, which is not applicable here.

Option C (self.assertEqual(my_func(), 'true')): This checks if my_func() returns the string 'true', which is not correct as my_func() returns a boolean True.

Option D (self.assertFalse(my_func())): This checks if my_func() returns False, which is the opposite of what is needed.

1 – D, 2 – F, 3 – A, 4 – E, 5 – B, 6 – G, 7 - C

To delete a directory and all of its contents (including read-only files) recursively without prompting for confirmation, the rm command with the -rf flags should be used.

rm -r: This option tells rm to remove directories and their contents recursively.

rm -f: This option tells rm to force the removal of files, ignoring nonexistent files and never prompting for confirmation.

Therefore, the correct command is rm -rf old_project. This command will recursively remove the old_project directory and all its contents without any confirmation prompts, regardless of file permissions.

References: Cisco DevNet Associate Certification Guide, Chapter on Linux and Bash Commands.

API keys should be stored securely to prevent unauthorized access. The best practice is to store them encrypted in a configuration file that is separate from the code. This approach ensures that sensitive information is not hardcoded in the source code, which could be exposed through version control or other means. Keeping API keys in encrypted configuration files also allows for better management and updating of keys without changing the application code.

When configuring a Cisco IOS XE device using RESTCONF, the default data-encoding method is XML. RESTCONF is a protocol used to access configuration data and operational data using a REST-like API, and it uses XML as the default encoding method for data exchange.

XML: Used as the default encoding method for RESTCONF.

x-form-encoding: Not used by RESTCONF.

YANG: A data modeling language used to model configuration and state data manipulated by NETCONF and RESTCONF, but not an encoding method.

YAML: Not used by RESTCONF.

To start a new branch in Git for developing a fix, the git checkout -b my-bug-fix command is used. This command creates a new branch called "my-bug-fix" and checks it out in one step, allowing you to start working on it immediately.

git checkout -b my-bug-fix combines the creation of the branch (git branch my-bug-fix) and switching to it (git checkout my-bug-fix) into a single command.

References:

Git Branching Basics

To create and switch to a new branch called "my-bug-fix" in Git, you use the git checkout -b command. This command creates the branch and switches to it in one step.

A. git checkout -b my-bug-fix - Correct. This command creates a new branch and switches to it. B. git branch -b my-bug-fix - Incorrect. The -b option is not valid with git branch. C. git branch my-bug-fix - This creates a new branch but does not switch to it. D. git checkout my-bug-fix - This switches to an existing branch but does not create a new one.

References:

Git Branching - Creating a Branch

The Model-View-Controller (MVC) design pattern provides several advantages, including the ability to present multiple views of the same data to different user groups and the separation of concerns by dividing the application into three interconnected components.

A. to enable multiple views of the same data to be presented to different groups of users - Correct. MVC allows different views to display the same data, enhancing flexibility and usability. B. to provide separation between the view and the model by ensuring that all logic is separated out into the controller - Correct. MVC promotes the separation of concerns, making the application easier to manage and scale. C. to ensure data consistency, which requires that changes to the view are also made to the model - Incorrect. This is not a primary advantage of MVC; changes to the view do not directly affect the model. D. to ensure that only one instance of the data model can be created - Incorrect. This is not a characteristic or advantage of MVC. E. to provide only a single view of the data to ensure consistency - Incorrect. MVC supports multiple views.

References:

MVC Design Pattern

Agentless configuration management systems, such as Ansible, do not require agents to be installed on the managed hosts. Instead, they leverage existing protocols and services to perform configuration tasks.

Agentless Approach: These systems rely on protocols like SSH (for Unix/Linux) or WinRM (for Windows) to communicate with and manage the hosts.

No Agent Installation: Managed hosts do not need any additional software (agents) installed, which simplifies management and reduces overhead.

Interpreters: They may require the managed hosts to have an interpreter for scripts (e.g., Python) but primarily use existing network protocols for communication.

Option D correctly identifies that agentless configuration management systems use existing protocols to interface with managed hosts.

The error code 401 indicates an unauthorized request, which can often result from using an incorrect API endpoint. To solve this problem, ensure that the API URL correctly matches the endpoint for retrieving the device list. This URL must point to the correct API endpoint as specified by the Cisco DNA Center API documentation.

References:

Cisco DevNet Associate Study Guide: Interacting with Cisco DNA Center APIs (Chapter 7, Section: Using API Endpoints and Proper Authentication).

The exhibit shows a unified diff output, which indicates changes made to files in a version control system (e.g., git). The files being edited are indicated by the diff --git lines.

Identifying Files: The diff output shows changes to two files:

ciscoaxl/axl.py: Indicated by the line diff --git a/ciscoaxl/axl.py b/ciscoaxl/axl.py.

setup.py: Indicated by the line diff --git a/setup.py b/setup.py.

Unified Diff Format: The format includes the file paths, lines added (+), and lines removed (-).

Options B and D are the correct answers as they correspond to the files setup.py and ciscoaxl/axl.py.

Using functions in code improves the development process by enabling faster code development. Functions help modularize the code, making it easier to manage, reuse, and debug, which speeds up the development process.

A. better user experience in the end product - Incorrect. This is not directly related to the use of functions in code. B. improves code performance - Incorrect. While functions can sometimes improve performance, the primary benefit is modularity and reuse. C. easier to compile the code - Incorrect. Functions do not inherently make the code easier to compile. D. faster code development - Correct. Functions make development faster by allowing code reuse and simplifying debugging.

References:

Cisco Programming Fundamentals

The task is to determine which command correctly outputs the page_id value from the JSON payload shown in the Python 3.7 script. Let’s analyze the options and the payload structure to verify the correct answer.

JSON Payload Analysis:

The JSON payload provided in the exhibit shows that items is a key in the top-level dictionary.

The value of items is a list of dictionaries, and each dictionary contains various keys, including page_id.

Code Analysis:

The JSON data returned by the get_json function is assigned to the variable items.

The goal is to access the page_id key within the first dictionary of the list associated with the items key.

Options Analysis:

Option A: print(items['items']['page_id'])

This will not work because items['items'] is a list, not a dictionary. Attempting to access ['page_id'] directly from a list will result in a TypeError.

Option B: print(items.get('items').get('page_id'))

This will also not work for the same reason as Option A. items.get('items') returns a list, and calling .get('page_id') on a list is invalid.

Option C: print(items.get('items')[0].get('page_id'))

This is correct. items.get('items') returns the list, [0] accesses the first element of the list (which is a dictionary), and .get('page_id') retrieves the value of the page_id key from that dictionary.

Option D: print(items['items']['page_id'].keys())

This will fail because items['items'] is a list and does not have a keys() method.

Correct Explanation:

The JSON structure contains a list under the key items.

To access page_id, we first need to get the first dictionary in this list ([0]).

We then access the page_id key in this dictionary.

Example:

print(items.get('items')[0].get('page_id'))

This code correctly navigates through the structure and retrieves the value associated with page_id.

References:

Python Documentation on Dictionaries: Python Docs

JSON Data Handling in Python: Python JSON

The Python script in the exhibit interacts with Cisco DNA Center APIs to query devices and execute commands. It collects the results of specific show commands from the devices.

Device Query: The script first queries for devices with the platformId of 'C9500-40X'.

Command Execution: It sends commands (show version, show ip int brief) to these devices.

Result Gathering: The script retrieves and processes the results of the executed commands.

Option A accurately describes the process automated by the script, which is to gather the results of the show version and show ip int brief commands.

To integrate changes from an existing branch named 'feat00304' into a single commit with the current working primary branch 'prodapp411926287', the git merge --squash command must be used. This command squashes all commits from the feature branch into a single commit before merging.

A. git rebase --merge feat00304 - Incorrect. This command does not perform a squash merge. B. git merge --squash feat00304 - Correct. This command squashes all commits from 'feat00304' into a single commit and then merges it. C. git push --rebase feat00304 - Incorrect. This command is used for pushing changes and rebasing, not for squashing commits. D. git checkout --squash feat00304 - Incorrect. This command is invalid.

References:

Git Merge Squash

Bare Metal environments refer to physical servers that run directly on the hardware without a hypervisor. They offer several characteristics related to application deployment:

Provide workloads with access to hardware features: Bare Metal environments allow applications to directly access hardware resources, which can be critical for performance-sensitive applications.

Suitable for legacy applications that do not support virtualization: Some older applications may not be compatible with virtualized environments or may require direct access to physical hardware, making Bare Metal servers an ideal choice.

Bare Metal environments: Offer direct hardware access and are suitable for certain legacy applications.

Not specifically designed for container-based workloads: While containers can run on Bare Metal, these environments are not specifically tailored for containers.

Not providing hypervisors: Bare Metal environments do not include a hypervisor layer, which is a feature of virtualized environments.

The cURL command is used to make HTTP requests from the command line. To retrieve a resource in JSON format using OAuth, the command must include the following:

Authorization header: Use the -H option to include the OAuth access token for authentication.

Accept header: Specify that the response should be in JSON format by using the -H option with Accept: application/json.

URL: Provide the URL of the API endpoint.

This command retrieves the specified resource from the API, using the provided OAuth token to authenticate the request and requesting the response in JSON format.

1 – B, 2 – D, 3 – A, 4 – C

VLANs (Virtual Local Area Networks) serve several purposes in a network. Two primary purposes are:

Segmentation of the Network: VLANs logically segment a network into different broadcast domains, which helps in managing and controlling broadcast traffic. This segmentation helps improve performance and security by isolating certain types of traffic from others.

Creating Broadcast Domains: Each VLAN is a separate broadcast domain. By using VLANs, a network administrator can reduce the size of broadcast domains, thereby reducing broadcast traffic and increasing the efficiency of the network.

These purposes are in line with Cisco's network design principles and best practices for using VLANs. References: Cisco DevNet Associate Certification Guide, Chapter on VLANs and their uses.

In the Bash shell, the output of a command can be redirected to a file using the > operator. This operator takes the standard output (stdout) of the command and writes it to the specified file.

Option B (devnet > output.txt): This redirects the output of the devnet command to a file named output.txt.

Option A (devnet & output.txt): This is not a valid redirection operator.

Option C (devnet < output.txt): This uses the file output.txt as input to the devnet command, which is not the requirement.

Option D (devnet I output.txt): This is not a valid redirection operator.

Webhooks are user-defined HTTP callbacks triggered by specific events. They are effective in scenarios where an automated response to an event is required. For example, informing a chat channel after a deployment event or sending an email after a transaction are practical uses of webhooks. These use cases leverage the real-time capabilities of webhooks to automate responses and notifications based on events.

References:

Cisco DevNet Associate Study Guide: Event-Driven Automation (Chapter 8, Section: Webhooks and Their Use Cases).

A developer is creating a script to interact with a REST API service that requires basic authentication. The correct combination of payload and headers using Basic Authentication with the provided Base64 encoded credentials is:

A. This option does not use headers correctly. B. Option B - Correct. This option correctly places the 'Authorization' header in the headers dictionary with 'Basic' authentication. C. This option uses 'Bearer' instead of 'Basic' for the 'Authorization' header. D. This option uses 'Bearer' instead of 'Basic' for the 'Authorization' header.

References:

HTTP Authentication

Base64 Encoding

In the provided network topology, Device E is positioned between Server 1 and Server 2. Device E, being a Layer 2 switch, will limit traffic between these servers by making forwarding decisions based on MAC addresses. If there are VLANs configured, Device E will ensure that traffic is segregated accordingly, allowing only specific traffic to pass between the servers as defined by the network policies.

References:

Cisco DevNet Associate Study Guide: Network Components (Chapter 2, Section: Switches and Their Role in Network Traffic Management).

A VLAN (Virtual Local Area Network) allows devices on one or more LANs to be grouped together as if they were on the same physical network, even if they are not.

Logical Segmentation: VLANs provide logical segmentation of networks, enabling devices to communicate as if they are on the same physical network.

Isolation and Flexibility: They offer isolation and flexibility in network design, improving security and reducing broadcast domains.

Option B is correct as VLANs create logical groupings of devices that communicate as if they are on the same physical LAN.

Model-driven programmability leverages models to represent the desired state of network configurations, allowing for programmatic and standards-based management. This approach ensures that configurations can be written consistently and automatically across different network devices, simplifying network management and reducing the risk of configuration errors.

References:

Cisco DevNet Associate Study Guide: Model-Driven Programmability (Chapter 5, Section: Benefits of Model-Driven Programmability).

The Cisco DevNet API documentation is the primary resource for understanding the meanings of response codes received from REST API calls. It provides comprehensive details about the API endpoints, response codes, and their interpretations, which helps developers troubleshoot and understand the responses they receive.

Edge computing involves processing data closer to where it is generated (the "edge" of the network) rather than sending it to a centralized data center or cloud for processing. This approach reduces latency and bandwidth usage, providing high-speed data processing capabilities. It is particularly beneficial for IoT implementations where real-time processing and response are crucial.

References:

Cisco DevNet Associate Study Guide: IoT and Edge Computing (Chapter 9, Section: Benefits of Edge Computing).

Cisco DNA Center is a comprehensive network management and command center for enterprise networks, providing centralized management, automation, security, and policy enforcement across both wired and wireless networks.

Cisco ACI: Primarily focuses on data center automation and policy enforcement.

Cisco DNA Center: Provides organization-wide automation, security, and policy enforcement capabilities for both wired and wireless networks.

Cisco Umbrella: Offers cloud security services.

Cisco SD-WAN: Focuses on software-defined wide-area networking solutions.

Cisco DNA Center is designed to bring agility and operational efficiency across the entire enterprise network by leveraging advanced automation and assurance capabilities.

The exhibit illustrates a Continuous Integration/Continuous Deployment (CI/CD) pipeline. This method involves continuous integration of code from multiple developers, automated testing, and continuous delivery/deployment to production. It ensures that code changes are automatically built, tested, and deployed, promoting efficient and reliable software development practices.

The script returns a 401 Unauthorized response, indicating that the request lacks proper authentication. To resolve this, you must include an Authorization header in the HTTP GET request. The value of this header should be the Base64 encoded string of the username and password in the format username:password. This is necessary to authenticate the request and receive a 200 OK response.

References:

Cisco DevNet Associate Study Guide: REST API Authentication Methods (Chapter 7, Section: HTTP Basic Authentication).

The Bash script performs the following steps within the loop:

Reads each line from sites.txt.

Copies template.conf to a new file in the /etc/nginx/sites-available directory for each site.

Creates a symbolic link to the new file in the /etc/nginx/sites-enabled directory.

Changes the ownership of the new files to www-data.

This process creates a configuration file for each site, creates a link to enable the site, and ensures the correct permissions.

Organizing code into modules allows for code reuse, which simplifies maintenance and improves efficiency. Modules encapsulate specific functionality, making it easier to manage and update. This approach reduces redundancy, as common functions can be written once and reused across multiple programs, leading to more manageable and maintainable codebases.

References:

Cisco DevNet Associate Study Guide: Software Development and Design (Chapter 3, Section: Modular Programming and Code Reuse).

JSON and XML are both used for data interchange, but they have differences in functionality:

JSON: JavaScript Object Notation natively supports arrays and other data structures like objects (dictionaries in Python). JSON is known for being lightweight and easy to parse and is often considered more human-readable due to its simple syntax.

XML: eXtensible Markup Language does not natively support arrays in the same straightforward manner as JSON. Instead, arrays in XML need to be represented using repeated elements, which can be more verbose and complex. XML is highly flexible and supports defining custom tags, but it is generally more complex and less human-readable compared to JSON.

Therefore, JSON's native support for arrays makes it simpler and more efficient for certain data structures compared to XML.

In this question, the network engineer is using the RESTCONF API to update information about device interfaces. The RESTCONF API uses the YANG data modeling language and can encode data in either XML or JSON format. The appropriate headers must be set to specify the content type and the format in which the data is expected.

RESTCONF API: This API allows network devices to be managed using web-based protocols, and it relies on the YANG data model to represent the configuration data.

Content-Type and Accept headers: These headers define the media type of the resource. The Content-Type header tells the server what type of data is being sent by the client. The Accept header indicates the type of data that the client can receive from the server.

Option A is the correct answer because it specifies the correct content type and accept headers for using XML with YANG data models in RESTCONF API calls.

An engineer writes a Python script that uses two different API calls to query Cisco DNA Center for the number of interfaces on a device. The engineer notices that the two API calls produce different results. The fewer interfaces returned for the same device when the 'get_all_interfaces' API call is used can be explained by pagination.

A. times out - Incorrect. A timeout would likely result in an error, not fewer results. B. rate limit - Incorrect. Rate limiting would slow down requests but not reduce the number of returned interfaces. C. pagination - Correct. The 'get_all_interfaces' API call might be paginated, meaning it returns results in chunks rather than all at once. D. invalid password - Incorrect. An invalid password would result in an authentication error, not fewer results.

References:

Cisco DevNet DNA Center Platform

API Pagination

The CALMS framework is used to assess and guide DevOps transformations. It stands for Culture, Automation, Lean, Measurement, and Sharing. Each element represents a critical area for improvement in DevOps practices.

Collaboration: Emphasizes teamwork and breaking down silos.

Lean: Focuses on eliminating waste, optimizing processes, and ensuring efficiency.

Sharing: Encourages transparency and knowledge sharing among teams.

Measurement: Involves monitoring and analyzing performance metrics to drive improvement.

Given that the team is struggling to complete releases on time due to increased overhead, targeting the Lean aspect can help streamline processes, reduce waste, and improve efficiency, ultimately helping them to meet their release deadlines.

A load balancer distributes incoming network traffic across multiple servers to ensure that no single server bears too much load. This helps in balancing the traffic load, improving performance, and enhancing the availability of the applications hosted on the servers.

To create a running container based on a tagged Docker image with the container port 8080 bound to port 80 on the host, you use the docker run command with the -p flag.

A. docker build -p 8080:80 alpine

- Incorrect. docker build is used to build an image, not run a container. B. docker exec -p 8080:80 alpine

- Incorrect. docker exec is used to run a command in a running container. C. docker start -p 8080:80 alpine

- Incorrect. docker start starts a stopped container but does not create one. D. docker run -p 8080:80 alpine

- Correct. This command runs a new container from the image and maps the ports.

References:

Docker Run Command

To ensure that changes in a file that already exists in a local repository are included in the next Git commit, the git add command must be executed. This command stages the changes in the specified file(s) so they will be included in the next commit.

A. git update - Incorrect. There is no git update command. B. git merge - Incorrect. This command is used to merge branches, not to stage changes. C. git add - Correct. This command stages changes in the working directory to be included in the next commit. D. git rebase - Incorrect. This command is used to reapply commits on top of another base tip.

References:

Git Basics - Recording Changes to the Repository

One of the primary benefits of test-driven development (TDD) is increased code quality. By writing tests before coding and continuously testing during development, developers ensure that the code meets the specified requirements and behaves as expected. This approach leads to more reliable, maintainable, and bug-free code.

To complete the get_auth_token() function in the script to obtain a valid authentication token using HTTP Basic Authentication, you need to use the requests library correctly. The correct approach involves using the requests.post() method with the HTTPBasicAuth function.

A. resp = requests.post(url, auth=HTTPBasicAuth(DNAC_USER, DNAC_PASSWORD)) token = resp.json()['Token'] return token

Correct. This option uses requests.post() and HTTPBasicAuth properly. It retrieves the token from the JSON response.

B. resp = requests.post(url, auth=(DNAC_USER, DNAC_PASSWORD)) token = resp.json()['Token'] return token

Incorrect. This option incorrectly passes the auth credentials as a tuple without HTTPBasicAuth.

C. resp = http.post(url, auth=HTTPBasicAuth(DNAC_USER, DNAC_PASSWORD)) token = resp.json()['Token'] return token

Incorrect. http is not a valid method from the requests library.

D. resp = http.post(url, auth=(DNAC_USER, DNAC_PASSWORD)) token = resp.json()['Token'] return token

Incorrect. This option uses http.post(), which is incorrect.

References:

requests - HTTP for Humans

Cisco DNA Center Platform

The 401 Unauthorized response indicates that the API call lacks proper authentication. To authenticate a request using a Bearer token, the correct headers must be included. The "Authorization: Bearer " header is the correct format for including a Bearer token in an API request. Additionally, specifying the correct content type can also be important, but in this case, the critical headers are related to authorization.

References:

Cisco DevNet Associate Study Guide: API Authentication (Chapter 7, Section: Authentication Methods for REST APIs).

The Dockerfile shown in the exhibit sets up an NGINX container with a delay before starting the NGINX service. It uses the ENTRYPOINT and CMD directives to define the commands that should be executed when the container starts.

ARG and ENV: These lines define and set an argument and environment variable for the delay.

ENTRYPOINT: Specifies the executable to run, in this case, /bin/sh.

CMD: Provides additional arguments to the ENTRYPOINT, which are -c and the command string to execute.

The combined command that will be executed is: /bin/sh -c "/bin/sleep 30 && nginx -g 'daemon off;'"

Simulation Environment: CML provides a realistic environment for testing network configurations and automation scripts before deploying them on actual devices.

Resource Verification: Engineers can use CML to ensure that their Ansible playbooks function correctly and make necessary adjustments before running the code in a live network.

Option D is the correct resource for verifying the code using a simulated network environment.

The sequence diagram shows the process where the API client first calls the /organizations endpoint to get the list of organization IDs. Then, for each organization, it makes a call to the /organizations/(orgId)/networks endpoint to retrieve the networks for that organization. Since there are two organizations, the GetAllNetworks function will make two parallel calls to the /organizations/(orgId)/networks endpoint, one for each organization.

References:

Cisco DevNet Associate Study Guide: Using Cisco Meraki APIs (Chapter 7, Section: Understanding Meraki API Calls and Endpoints).

The difference between YAML and JSON in terms of data structure representation is that YAML uses indentation to indicate structure, while JSON uses brackets and braces.

A. YAML uses spaces; JSON uses parentheses - Incorrect. JSON does not use parentheses. B. YAML uses indentation; JSON uses brackets and braces - Correct. YAML relies on indentation for structure, whereas JSON uses brackets and braces. C. YAML uses brackets and braces; JSON uses indentation - Incorrect. This is the opposite of the correct statement. D. YAML uses parentheses; JSON uses spaces - Incorrect. Neither format uses these exclusively.

References:

YAML vs. JSON

When an IP packet does not match any routes in the routing table, it is routed to the default gateway. The default gateway serves as a forwarding host that routes traffic from a local network to other networks or the Internet.

A. firewall - Incorrect. A firewall is a security device, not used for routing unmatched packets. B. load balancer - Incorrect. A load balancer distributes network or application traffic across multiple servers, not used for routing unmatched packets. C. central switch - Incorrect. A switch operates at the data link layer and does not perform IP routing. D. default gateway - Correct. The default gateway is used to route packets that do not match any other route in the routing table.

References:

Cisco Network Fundamentals

Model-driven programmability offers several benefits:

Model-driven APIs for abstraction and simplification: These APIs provide a higher level of abstraction, making it easier to manage and automate networks.

Models decoupled from transport, protocol, and encoding: This decoupling ensures that the same model can be used with different transport protocols, making the system more flexible and easier to integrate with various technologies.

The provided Ansible playbook automates the process of ensuring the nginx server is installed while removing apache2, and then updates all the packages to their latest versions.

Task 1: Ensures that apache2 is uninstalled (state: absent).

Task 2: Ensures that nginx is installed (state: present).

Task 3: Updates all packages to their latest versions (state: latest).

Option C accurately describes the process automated by the Ansible playbook.

In the response header shown, the "Content-Type" is specified. Response headers provide important metadata about the response, including the content type, which informs the client about the nature of the returned content (in this case, application/json).

Private IP addresses are used within private networks and are not unique globally. They can be reused in different private networks without conflict.

Non-unique Addresses: Private IP addresses do not have to be unique globally, allowing them to be reused in different networks.

Repetition in Local Networks: They can be repeated within different local networks as they are not routable on the public Internet.

Options C and D correctly describe properties of private IP addresses.

When authenticating a RESTCONF API session with a router running Cisco IOS XE Software, basic authentication is required. This involves sending a username and password encoded in Base64 as part of the HTTP headers.

In the provided cURL command, the developer needs to include an authorization header with the access token to authenticate the API request. Without proper authentication, the server will reject the request and return an error code.

The Python script uses nested loops to gather information:

The first loop checks for the "ACME" organization.

If found, it collects information about the networks in that organization.

The second loop checks for the "BLDG21" network.

If found, it gathers information about clients in that network.

This process effectively provides the BLDG21 network information if it is part of the ACME organization.

HTTP status codes in the 2xx range indicate that a request has been received, understood, and processed successfully.

A. 2xx - Correct. This range of status codes indicates successful responses. B. 3xx - Incorrect. This range of status codes indicates redirection messages. C. 4xx - Incorrect. This range of status codes indicates client errors. D. 5xx - Incorrect. This range of status codes indicates server errors.

References:

HTTP Status Codes

NETCONF (Network Configuration Protocol) allows for the exchange of configuration data and state information between a network device and a management system using XML-encoded messages over a secure SSH connection.

A. allows Python scripts to be executed externally from a network device - Incorrect. This is not a capability of NETCONF. B. uses JSON to encode data in its content layer - Incorrect. NETCONF uses XML for encoding data. C. allows XML messages to be exchanged via the SSH protocol - Correct. NETCONF uses XML to encode configuration data and state information, and it uses SSH as the transport protocol. D. exposes a web-based interface - Incorrect. NETCONF itself does not provide a web-based interface; it operates over SSH.

References:

NETCONF Protocol

pyATS (Python Automated Test Systems) is a comprehensive testing framework developed by Cisco, designed specifically for automating the testing of network devices. It provides a robust and flexible environment for creating and running tests on network devices and simulating network automation scenarios.

pyATS enables the creation of reusable test scripts and workflows that can be applied across different network environments and devices.

It supports various protocols and devices, allowing for extensive testing coverage.

It integrates well with other Cisco network automation tools and frameworks, making it a versatile choice for network engineers and developers.

References:

Cisco DevNet pyATS documentation

Cisco DevNet Associate Certification Guide

The main security issue in this scenario is the transmission of credentials in cleartext over HTTPS. Even though HTTPS provides a secure transport layer, the credentials should still be protected, such as by using secrets or encryption. Additionally, setting logging to debug and potentially exposing these credentials in logs is also a security concern.

Cleartext Credentials: Sending credentials in cleartext within the webhook payload can expose them if HTTPS is not configured correctly or if intercepted by an attacker.

Debug Logging: Enabling debug logging can expose sensitive information, including credentials, in logs.

Option B highlights the risk of transmitting credentials unencrypted over HTTPS, which can lead to credential leakage.

The data plane, also known as the forwarding plane, is responsible for handling the actual movement of packets through the network device, including Quality of Service (QoS). QoS involves managing and prioritizing network traffic to ensure that critical applications receive the necessary bandwidth and performance levels. The data plane processes and forwards data packets based on the policies set by the control plane.

References:

Cisco DevNet Associate Certification Guide

Cisco Networking Essentials, Chapter on Network Device Planes

The provided Python script interacts with an ACI (Application Centric Infrastructure) environment. It logs into the ACI fabric and collects information about groups. Specifically, the getstuff function uses an API call to retrieve data from the ACI and processes it to extract group information.

The unified diff format is used to display differences between two files. The content of the file2.py file shows the added lines in the comparison.

Unified Diff Format: The format uses + to indicate lines added in file2.py and - to indicate lines removed.

Line Addition: Line 93 of file2.py has the 'DEVICE-STATS' line, as indicated by the + symbol in the diff output.

References:

Understanding Unified Diff Format: Unified Diff

To obtain a token from the Cisco DNA Center API using HTTP Basic Authentication, the requests library in Python is used. The missing line of code in the snippet should set up HTTP Basic Authentication as follows:

auth=HTTPBasicAuth(user,password)

HTTPBasicAuth: This is a class from the requests.auth module that handles HTTP Basic Authentication.

user, password: These are the credentials required for authentication.

The correct line of code that completes the script to obtain a token from Cisco DNA Center API is:

python

Copy code

auth=HTTPBasicAuth(user,password)

References:

Requests Library Documentation - HTTPBasicAuth

Cisco DevNet Associate Certification Guide

One of the key principles of a code review process is to ensure that naming standards are consistent. This helps maintain code readability, understandability, and maintainability. Consistent naming conventions reduce the cognitive load for developers when reading and understanding the code, making it easier to manage and less prone to errors.

References:

Atlassian - Code Review Best Practices

Cisco DevNet Associate Certification Guide

YAML and JSON are both data serialization formats often used in configuration files. One of the key differences is that YAML supports comments, whereas JSON does not.

Comments: YAML allows comments, which makes it easier to add explanatory notes within the configuration files.

Data Representation: Both formats are used to represent data structures, but YAML is often considered more human-readable.

Option B is correct as it highlights the difference that YAML supports comments while JSON does not.

A code review process involves evaluating and examining another developer's code to identify potential issues, bugs, and improvements before the code is merged into the main codebase. It helps in maintaining code quality and catching errors early in the development cycle.

Error Detection: Code reviews help detect and eliminate common mistakes and bugs that developers might overlook.

Knowledge Sharing: They promote knowledge sharing and learning among team members.

Code Quality: Ensures that the code adheres to the coding standards and best practices.

Option D is correct as the primary benefit of code reviews is to eliminate common mistakes during development.

To minimize the security risk, storing the username and password in a vault is the best practice. A vault, such as HashiCorp Vault or AWS Secrets Manager, securely stores and manages sensitive information, providing encryption and access control. This approach ensures that credentials are not hard-coded or stored in insecure locations, reducing the risk of exposure.

The control plane in networking is responsible for routing and signaling functions. Protocols like BGP (Border Gateway Protocol) operate on the control plane because they manage the routing information and decisions that control how packets are forwarded through the network. BGP specifically is used to exchange routing information between different autonomous systems on the internet.

References:

Cisco Networking - Control Plane

Cisco DevNet Associate Certification Guide

Rate limiting is a technique to control the rate of incoming and outgoing traffic to or from a network. If rate limiting is not implemented, excessive API requests can overwhelm the server, causing long response times and abandoned requests.

Abandoned Requests: When a server is overwhelmed with too many requests, it may not process them all, leading to abandoned requests.

Long Response Times: Without rate limiting, the server might be handling more requests than it can efficiently process, resulting in delayed responses.

Solution: Implementing rate limiting ensures that the server processes requests at a manageable rate, improving performance and reliability.

References:

Rate Limiting and API Performance: Understanding Rate Limiting

Webhooks typically use the HTTP POST method to notify a listener about an event change. When an event occurs, the source system sends an HTTP POST request to the listener's URL with the details of the event, allowing the receiving system to process and respond to the event.

References:

Cisco DevNet Documentation - Webhooks

Cisco DevNet Associate Certification Guide

In Test-Driven Development (TDD), the process starts with writing tests before writing the actual code. The primary purpose of running tests before writing the code is to ensure that the tests fail initially. This failure demonstrates that the tests are correctly identifying the absence of the desired functionality or the presence of bugs. Once the tests are verified to fail for the expected reasons, the developer then writes the minimal code necessary to pass the tests, ensuring that the new functionality works as intended and that the codebase is continuously tested.

References:

Test-Driven Development by Example

Cisco DevNet Associate Certification Guide

To protect secrets such as API URLs, shared keys, and other application configurations, it is best practice to: C. Ensure they never appear in plaintext at rest or in transit. Encrypt sensitive data both when it is stored (at rest) and when it is transmitted over the network (in transit). This prevents unauthorized access and exposure. E. Always store secrets in a secure vault. Use dedicated secret management tools like HashiCorp Vault, AWS Secrets Manager, or Azure Key Vault to store and manage sensitive information securely. These tools provide mechanisms for access control, audit logging, and automatic rotation of secrets.

References:

Securing Secrets

HashiCorp Vault

AWS Secrets Manager

RESTCONF is a protocol used for accessing data defined in YANG, using RESTful principles. It is suitable for retrieving configuration data in JSON format from a Cisco CSR 1000 V instance. RESTCONF allows network devices to be managed using HTTP methods, and it supports both XML and JSON as data formats, making it ideal for outputting device configurations in JSON.

The bash script in the exhibit performs the following actions step-by-step:

#!/bin/bash - This is the shebang line that tells the system this script should be run with the bash shell.

apt-get update - This command updates the package lists for upgrades for packages that need upgrading, as well as new packages that have just come to the repositories.

apt-get -y install git - This command installs git automatically confirming the installation with -y.

cd Code/Network_Config - This command changes the directory to Code/Network_Config.

mkdir PRODUCTION - This command creates a new directory named PRODUCTION.

cd PRODUCTION - This command changes the directory to the newly created PRODUCTION directory.

touch state.yml - This command creates an empty file named state.yml.

vi state.yml - This command opens the state.yml file in the vi editor.

Therefore, based on the above script analysis:

A directory called PRODUCTION is created (Answ

Comprehensive Detailed Step by Step Explanation with ReferencesA sandbox environment is an isolated testing environment that mimics a live network. It allows engineers and developers to run scripts and test code without affecting the production network. Cisco provides sandboxes through the DevNet portal, which are always available for testing and experimentation with network automation and programmability. Using a sandbox helps monitor the live execution of code in a controlled and safe manner, ensuring that any potential issues do not impact the actual network.

References:

Cisco DevNet Sandboxes

Cisco DevNet Associate Certification Guide

The TCONNECT protocol is part of the OSI transport layer, where TCONNECT confirm is the API called when the remote transport user (TU) responds to a connection request from the local TU.

TCONNECT confirm: This is the final step in establishing a transport connection, where the remote TU confirms the connection request from the local TU.

Sequence: The sequence typically involves TCONNECT request, TCONNECT indication, TCONNECT response, and finally TCONNECT confirm.

References:

OSI Transport Protocols: OSI Transport Layer

To set an environmental variable in a Linux system using Bash, the export command is used. This command sets the environment variable for the current session, and any subsequent commands or processes will inherit this environment variable.

For example, to set an environment variable named "website" with the value "cisco.com", you use the following command:

export website="cisco.com"

This sets the variable website and makes it available to any subprocesses started from the shell.

References:

GNU Bash Reference Manual - Bash Builtin Commands

Cisco DevNet Associate Certification Guide

NETCONF (Network Configuration Protocol) operates over TCP port 830. It is a protocol defined for managing network devices and configurations. NETCONF provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses XML as its data encoding format and allows for easy automation of network configuration tasks.

References:

Cisco DevNet Associate Certification Guide

RFC 6241 - Network Configuration Protocol (NETCONF)

A default gateway is a router or network device that serves as an access point to another network, often the internet, when no other route is specified for a given data packet. In other words, it is used to forward traffic from the local subnet to different subnets, including external networks. When a host needs to communicate with a device on a different subnet, it sends the traffic to the default gateway, which then routes the traffic accordingly.

References:

Cisco DevNet Associate Certification Guide

Cisco Networking Essentials, Chapter on Routing and Switching Basics

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

The Waterfall model is a linear and sequential approach to software development. In Waterfall, all requirements are specified at the beginning of the project, and each phase (e.g., design, implementation, testing) must be completed before moving on to the next. This makes it less adaptable to changes once the project is underway.

Agile, on the other hand, is an iterative approach that allows for flexible responses to changes in requirements. Agile development is organized into small, incremental cycles called sprints, which typically last 1-4 weeks. During each sprint, a small portion of the project is developed, and changes can be incorporated based on feedback and evolving requirements.

The command git branch -D test forcefully deletes the local branch named test, even if it has unmerged changes.

Deleting Branches: git branch -D is used to delete a branch forcefully.

Force Deletion: The -D flag forcefully deletes the branch regardless of its merge status.

Option C correctly describes the action of the command, which is to delete the test branch.

Importing Libraries: The script imports the requests and json libraries necessary for making HTTP requests and handling JSON data.

URLs Definition: The url1 variable holds the Webex API endpoint for creating webhooks, and url2 is the target URL where Webex will send the messages.

Token Handling: The token variable contains the OAuth2 token required for authentication with the Webex API.

Setting Headers: The headers dictionary includes the Content-Type set to application/json and the correct Authorization header that uses the Bearer token.

Payload Preparation: The payload dictionary contains the necessary information to create the webhook, including its name, target URL, resource type, and event.

Making the Request: The requests.request method sends a POST request to the Webex API endpoint with the specified headers and payload.

Printing the Response: The response from the Webex API is printed out, encoded in 'utf-8'.

During the integration step of the CI/CD pipeline, code from multiple developers is combined. This step involves compiling the code and running tests to ensure that the different components work together correctly. It is a critical phase for identifying integration issues early in the development cycle.

Device-level management allows for more granular control over the specific settings and configurations of individual network devices. This is beneficial in scenarios where fine-tuning of device settings is required, and where certain configurations may not be exposed or supported by the overarching controller. Controller-level management, on the other hand, abstracts many device-specific settings to provide a more uniform and simplified management interface, which may not support all the detailed configurations available at the device level.

References:

Cisco DevNet: Device vs. Controller Management

from ucsmsdk.ucshandle import UcsHandle

connection = UcsHandle("10.10.20.113", "ucspe", "ucspe")

connection.login()

orgs = []

ucsm_orgs = connection.query_classid("orgOrg")

for org in ucsm_orgs:

temp_org = {"name": org.name, "dn": org.dn, "rn": org.rn}

orgs.append(temp_org)

print(orgs)

Understanding the UCSHandle Class:

Purpose: The UcsHandle class is used to interface with the UCS Manager.

Parameters: It requires parameters like IP address, username, password, port, secure, and proxy.

Python Script Explanation:

Importing UcsHandle: The first step is to import the UcsHandle class from the ucsmsdk.ucshandle module.

Creating a Connection: An instance of UcsHandle is created with the UCS Manager's IP address, username, and password.

Login: The login() method is called on the UcsHandle instance to establish a session with the UCS Manager.

Querying Organizations: The query_classid() method is used to retrieve objects of a specific class, in this case, "orgOrg" which represents organizations.

Looping through Results: The script iterates over the retrieved organizations, extracting their name, distinguished name (dn), and relative name (rn), and appending this information to the orgs list.

Printing Results: Finally, the orgs list is printed, which contains the details of all the organizations.

References:

Cisco DevNet Associate Certification Guide, Sections on UCS Manager API and Python SDK

UCS Python SDK Documentation

Refer to the exhibit which shows a sequence diagram illustrating a client-server interaction. The correct sequence of steps that match the code snippet is as follows:

Step 1: POST /events - The client posts an event to the server.

Step 2: GET /messages/<messageId> - The client retrieves the message details from the server using the message ID.

Step 3: Response /messages/<messageId> - The server responds with the message details.

Step 4: GET /team-memberships?teamId=<teamId> - The client retrieves team membership details using the team ID.

Step 5: POST /message - The client posts a message.

Step 6: Response /message - The server responds with the message confirmation.

The correct code snippet represents the sequence diagram correctly:

@flask_app.route('/events', methods=['POST'])

def webex_teams_webhook_events():

json_data = request.json['data']

response = requests.get(MESSAGE_URL + json_data['id'], headers=headers)

if response.json()['text'] == 'Alert':

response = requests.get(TEAM_MEMBERSHIPS_URL, headers=headers, params=params)

for info in response.json()['items']:

data = {'personId': info['personId'], 'text': 'Alert'}

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

Cisco Webex offers a range of collaboration capabilities, including real-time messaging, video conferencing, and integration with various productivity tools. Specifically, Webex allows users to:

Get Space History: Users can retrieve historical messages and files shared within a space, ensuring they have access to all past communications and documents.

Real-Time Notifications: Webex provides notifications when new messages are posted in spaces, allowing users to stay updated with ongoing conversations and respond promptly.

These features enhance the collaborative experience by ensuring users can keep track of conversations and receive timely updates.

References:

Cisco Webex Features

Network Time Protocol (NTP) is used to synchronize the clocks of network devices to a common reference time. This is crucial for ensuring accurate time stamps in logs, coordinating time-sensitive operations, and maintaining consistent time across all devices in a network.

NTP: Synchronizes clocks of network devices to ensure they have the same time, which is essential for accurate event logging and coordination.

Other Protocols:

DNS: Resolves domain names to IP addresses.

SNMP: Used for monitoring network devices.

NAT: Translates private IP addresses to public IP addresses.

References:

Cisco DevNet Associate Certification Guide

Cisco NTP Overview

Before running an Ansible playbook to configure Cisco Nexus devices using the NX REST API, it's important to verify that the REST API requests work as expected. The best resource for this purpose is Cisco Open NX-OS, which provides detailed information and tools for working with the NX-OS REST API.

Cisco Open NX-OS: This platform provides extensive documentation, tools, and examples for using the NX-OS REST API. It is an ideal resource for testing and validating REST API requests before automation.

Other Resources:

Cisco NX-OS SDK: Provides software development tools for NX-OS but is less focused on REST API verification.

Cisco Learning Labs: Offers hands-on labs for learning, but not specifically for REST API testing.

Cisco Code Exchange for Nexus: Provides code examples, but not specifically for testing REST API requests.

References:

Cisco DevNet Associate Certification Guide

Cisco Open NX-OS

Top of Form

Bottom of Form

An ICMP "time exceeded in-transit" message indicates that the TTL (Time to Live) of a packet has expired. The TTL value is a counter that decreases by one each time the packet passes through a router. When the TTL reaches zero, the packet is discarded, and an ICMP "time exceeded" message is sent back to the sender. This typically happens when the packet takes too many hops or the destination is too far away, causing the TTL to expire before reaching the destination.

The control plane in a network device is responsible for routing and signaling. Protocols such as BGP (Border Gateway Protocol) and OSPF (Open Shortest Path First) are integral to the control plane.

BGP (Border Gateway Protocol): BGP is used for exchanging routing information between autonomous systems on the internet, making it a crucial control plane protocol.

OSPF (Open Shortest Path First): OSPF is an interior gateway protocol used for routing within an autonomous system, also part of the control plane.

References:

BGP and OSPF Protocol Details: BGP, OSPF

A router is a network component that enables communication between different broadcast domains by forwarding data packets between them based on their IP addresses.

Broadcast Domains: A broadcast domain is a network segment where a broadcast frame is forwarded to all devices.

Router Function: Routers separate broadcast domains, allowing communication between them by routing packets based on their destination IP addresses.

References:

Network Components: Routers and Broadcast Domains

The primary purpose of grouping devices in a VLAN (Virtual Local Area Network) is to segment a network such that devices within the same VLAN can communicate as if they are on the same physical network, regardless of their actual physical location. This allows for logical grouping of devices, providing improved network management and security.

In a CI/CD (Continuous Integration/Continuous Deployment) pipeline, it is a common procedural component that every test must pass for the pipeline to continue its execution. This ensures that only code that meets the quality standards and passes all tests is deployed, thereby reducing the risk of introducing bugs or issues into the production environment.

When using OAuth2 authentication for accessing a protected resource via a REST API, the typical flow involves obtaining an access token which can then be used to authenticate subsequent API requests. The correct process is:

POST Call to /login: Make a POST request to the /login endpoint with the user credentials (username and password) in the request body. This call will authenticate the user and, if successful, return an access token.

Use the Token: Use the retrieved token by including it in the Authorization header (usually as a Bearer token) in the request to access the protected resource, in this case, the /item endpoint.

References:

OAuth 2.0 Authorization Framework - RFC 6749

Version control systems (VCS) are essential for managing changes to code and files in a project. They track all modifications, enabling multiple users to work collaboratively while maintaining a history of changes.

Tracking Changes: VCS keeps a detailed history of changes made to files, including who made the change and when.

Collaboration: Multiple users can work on the same project simultaneously without overwriting each other's work.

Reverting Changes: It allows reverting to previous versions if a mistake is made.

Option B is correct as it highlights the primary benefit of version control—keeping track of all changes to the files.