200-901 Sample Questions Answers

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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DNS (Domain Name System) is the service that provides a directory lookup for IP addresses and host names. DNS translates human-readable domain names (like www.example.com ) into IP addresses that computers use to identify each other on the network.

DNS: Converts domain names into IP addresses and vice versa.

DHCP: Dynamically assigns IP addresses to devices on a network.

SNMP: Used for network management and monitoring.

NAT: Translates private IP addresses to a public IP address for accessing the internet.

References:

Cisco DNS Documentation

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.

The YANG structure shown defines a leaf IPPeer that can be either an IPv4 address or an IPv6 address. The third JSON example correctly represents this union type by using an array with both possible types included:

"IPPeer": [

"10.1.1.1",

"2001:db::1"

]

}

This correctly reflects the YANG definition, where IPPeer can be either type specified in the union.

References:

YANG - Data Modeling Language

Cisco YANG Models

gRPC = C, NETCONF = A, RESTCONF = B, D

OR

Meraki APIs offer various functionalities, including:

Retrieve live streams from a Meraki Camera (A): Meraki provides API endpoints to access live video streams from its cameras, enabling integration with custom applications.

Configure network devices via the Dashboard API (C): The Meraki Dashboard API allows for comprehensive configuration and management of Meraki network devices.

References:

Cisco Meraki API Documentation (details on the capabilities of Meraki APIs)

Cisco DevNet Associate Exam Topics: APIs and Automation (understanding how to use APIs for network configuration and monitoring)

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.

 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.

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

1 – B, 2 – D, 3 – A, 4 – C

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

The described behavior, where an automation script fails to connect to an internal server exactly 50% of the time from different clients, suggests an issue with a load balancer. Load balancers distribute incoming network traffic across multiple servers to ensure reliability and performance. If a load balancer is misconfigured or if one of the backend servers is down, the connection might fail intermittently, which aligns with the described 1 out of 2 failure rate.

When a developer is writing an application that interacts with a REST API, the status code of the response is a critical element used in conditional checks. The status code provides information about the success or failure of the request. Common status codes include:

200: OK (The request was successful).

201: Created (The resource was successfully created).

400: Bad Request (The server could not understand the request due to invalid syntax).

401: Unauthorized (Authentication is required and has failed or has not been provided).

404: Not Found (The requested resource could not be found).

By checking the status code, the application can determine if the request was successful and handle errors appropriately.

When users cannot access a web server and the captured traffic shows an ICMP packet that reports "communication administratively prohibited," it indicates that there is a filtering device along the path, such as a router or firewall, that is intentionally blocking the traffic. This usually happens because of an access control list (ACL) that is set to deny the traffic to the webserver.

Access Control Lists (ACLs): ACLs are used in networking to control the flow of traffic into or out of a network. They can be configured on routers, firewalls, or other devices to allow or deny traffic based on IP addresses, protocols, ports, and other criteria.

ICMP Messages: ICMP (Internet Control Message Protocol) is used by network devices to send error messages and operational information. The "communication administratively prohibited" message specifically indicates that a device along the path has been configured to block the traffic.

Troubleshooting Steps:

Check ACL Configuration: Verify the ACL settings on all devices along the path to ensure that they are not blocking the required traffic.

Review Network Device Logs: Check logs on routers and firewalls for entries that match the blocked traffic.

Modify ACLs: If an ACL is found to be blocking the traffic, modify it to allow the required traffic to pass through.

References:

Cisco Documentation on ACLs: Access Control Lists

Cisco ICMP Overview: ICMP Messages

The primary function of the default gateway in a network is to forward traffic to different subnets. It acts as an intermediary that routes traffic from a local network to other networks, including the Internet.

Default Gateway: A router or network device that routes traffic from a local subnet to other subnets or networks. It serves as an access point or IP router that a networked computer uses to send information to a computer in another subnet or network.

References: Cisco DevNet Associate Certification Guide, Chapter on Networking Basics and IP Routing.

The Ansible script provided configures the following:

GigabitEthernet0/1 is set as a trunk port with VLANs 6-8 allowed.

GigabitEthernet0/2 and GigabitEthernet0/3 are access ports assigned to VLAN 6.

GigabitEthernet0/4 is an access port for VLAN 7.

GigabitEthernet0/5 is an access port for VLAN 8.

Thus, the correct interpretations are: B. Traffic from ports 0/2 to 0/5 can flow on port 0/1 due to the trunk. D. GigabitEthernet0/2 and GigabitEthernet0/3 are access ports for VLAN 6.

SSH (Secure Shell) is a protocol that provides a secure channel over an unsecured network by using encryption. It operates over TCP port 22 and is commonly used for remote login and command execution on network devices and servers. SSH ensures secure communication between the client and server by encrypting the session.

References:

Cisco DevNet Associate Study Guide: Understanding Network Protocols (Chapter 2, Section: Common Network Protocols and Ports).

The Waterfall method is a sequential software development process where a phase begins only after the previous phase has ended. In contrast, Agile development involves iterative processes where phases run in parallel and are continuously improved upon.

A. Waterfall increases agility to implement faster while Agile promotes reliability - Incorrect. This is the opposite of the typical characteristics of these methods. B. A phase begins after the previous phase has ended in Waterfall while Agile phases run in parallel - Correct. Waterfall is linear and sequential, while Agile is iterative and parallel. C. Customers get feedback during the process in Waterfall while they can see the result at the end in Agile - Incorrect. Agile involves continuous feedback, whereas Waterfall typically provides feedback only at the end. D. Requirements can be updated in Waterfall while in Agile it should be gathered in the beginning - Incorrect. Requirements in Agile can be updated continuously, while Waterfall requires requirements to be defined upfront.

References:

Waterfall vs. Agile Methodologies

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.

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.

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

A MAC address (Media Access Control address) is a unique hardware address assigned to the network interface of a device. It is used for network communication at the data link layer of the OSI model.

A. unique network address that identifies the network interface of a device - Incorrect. This describes an IP address. B. unique network interface address that is provided by the DHCP server - Incorrect. MAC addresses are hardware-based, not provided by DHCP. C. unique hardware address that identifies the network interface of a device - Correct. This is the correct definition of a MAC address. D. unique hardware interface address that is provided by the central switch - Incorrect. MAC addresses are not provided by switches.

References:

Cisco MAC Address Basics

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 401 Unauthorized status code indicates that the request lacks valid authentication credentials. When using OAuth2 for authenticating with the Cisco Webex API, the correct approach is to include a Bearer token in the Authorization header.

header = {"Authorization": "Bearer YOUR_TOKEN"}

This option correctly formats the Authorization header, which is necessary for the Webex API to authenticate the request. The Bearer token is a type of token used by OAuth2 to access protected resources.

Authorization Header: The header must contain the key "Authorization" with the value formatted as "Bearer YOUR_TOKEN".

Bearer Token: The Bearer keyword followed by a space and the token itself is the correct way to pass the OAuth2 token in the header.

Option B:

Incorrect because it uses "Authentication" instead of "Authorization".

Option C:

Incorrect because it combines Authentication and Bearer incorrectly without a space.

Option D:

Incorrect for the same reason as Option C.

References:

Cisco Webex API Authentication

OAuth2 Authorization Header =====================

RESTCONF and YANG are used for network configuration and management on Cisco IOS XE devices. RESTCONF provides a REST-like interface for accessing YANG-defined data models, allowing engineers to change configurations such as netmasks through programmable interfaces.

References:

Cisco DevNet Associate Study Guide: Network Programmability and Automation (Chapter 6, Section: Using RESTCONF and YANG).

In the provided Python function enable_function, the parameters are if_name, if_status, and if_type, which correspond to the interface name, status (enabled/disabled), and interface type respectively.

Function Parameters: The function enable_function is designed to take three parameters: the interface name (if_name), the status (if_status), and the type (if_type).

Correct Order and Values: To enable the interface named "Loopback1", you need to pass the correct values in the order they are defined in the function.

Option A correctly calls the function with the interface name "Loopback1", the status true (enabled), and the interface type 'iana-if-type:softwareLoopback'.

Telnet is a protocol used for accessing remote computers over a TCP/IP network, and it runs over TCP port 23.

Telnet Protocol: Telnet allows remote command-line interface access to network devices and servers.

Port 23: The standard port for Telnet is TCP port 23.

Option D is correct as Telnet operates over TCP port 23.

In the Ansible playbook, the last task uses the apt module with state: absent and purge: yes for the webexbot package. This configuration ensures that the package is uninstalled and all associated configuration files are removed. This is different from a simple uninstall, which would leave configuration files behind.

References:

Cisco DevNet Associate Study Guide: Automation with Ansible (Chapter 7, Section: Ansible Playbook Examples and Syntax).

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 docker build command is used to build an image from a Dockerfile. The -t option tags the image with a specified name and tag.

Tagging: The docker tag command associates an image ID with a repository and tag.

Building with Tag: The correct command to build the Docker image and tag it as local/app:0.4 is docker build -t local/app:0.4.

Option D is the correct command to build and tag the image.

A containerized application environment meets the requirements of being hardware-independent and allows for the installation and management of the environment to be fully automated. Containers package the application and its dependencies together, ensuring consistency across different environments. This method is also highly compatible with automation tools and orchestrators like Kubernetes, making deployment and management easier and more efficient.

References:

Cisco DevNet Associate Study Guide: Understanding Application Deployment (Chapter 4, Section: Containers and Their Benefits).

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.

VLANs (Virtual Local Area Networks) provide multiple benefits, including segmenting the broadcast domain, which reduces unnecessary traffic and improves network performance. They also enable the logical grouping of devices across different physical Layer 2 switches, enhancing network management and security by isolating traffic between different VLANs.

References:

Cisco DevNet Associate Study Guide: Network Segmentation and VLANs (Chapter 4, Section: Understanding VLANs and Their Benefits).

Top of Form

Bottom of Form

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 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 provided documentation outlines how to use Basic HTTP Authentication with the Cisco AMP API. The correct method involves encoding the client ID and API key in base64 format and then including them in the authorization header. However, in the given scripts, the use of the requests library’s auth parameter directly with the client ID and API key is also a valid method.

Option A correctly uses the requests library to make an API call with the client ID and API key. This method is supported and valid as per the documentation.

python

Copy code

import requests

amp_client_id = 'alb2c3d4e5f6g7h8i9j0'

amp_login_password = 'l0g1n_p@ssw0rd'

url = 'https://api.amp.cisco.com/v1/version '

request = requests.get(url,

auth=(amp_client_id, amp_login_password))

print(request.json())

Client ID and API Key: amp_client_id and amp_login_password are set with the values provided.

URL: The URL for the AMP API endpoint is correctly set.

GET Request: The requests.get method is used with the auth parameter that takes a tuple of the client ID and API key.

Response: The response is printed in JSON format.

Option B:

Does not use the auth parameter or a header for Basic Authentication, thus it will fail.

Option C:

Uses a single amp_auth_token which does not follow the provided documentation method.

Option D:

Incorrectly uses the auth parameter with a concatenated client ID and API key without specifying Basic Authentication in the header.

References:

Cisco AMP for Endpoints API Documentation

Requests: Authentication

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;'"

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

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

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.

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

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

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).

Synchronous API requests and asynchronous API requests differ primarily in how and when the client receives a response from the server.

Synchronous API Request: In a synchronous API call, the client sends a request to the server and waits for a response. The client is blocked during this time, meaning it cannot perform other tasks until the server responds. The key characteristic is that the client is able to access the results immediately after the request is processed. This is suitable for operations that need an immediate response and where the processing time is relatively short.

Asynchronous API Request: In an asynchronous API call, the client sends a request and continues its process without waiting for the server to respond. The server processes the request and sends the response back to the client at a later time. The client might receive a task ID (option A), subscribe to a webhook (option B), or poll for status (option D) to check when the operation is complete.

The EXPOSE instruction in a Dockerfile informs Docker that the container listens on the specified network ports at runtime. This does not publish the ports to the host machine, but it allows them to be connected to from other containers.

A. Local port 8080 of the container that launched with this docker image is accessible from co-hosted containers and external clients - Incorrect. The EXPOSE instruction does not make the port accessible to external clients. B. Local port 8080 is not reachable at all because no IP address is specified along with the EXPOSE command of the Dockerfile - Incorrect. The EXPOSE instruction does not require an IP address. C. Local port 8080 is accessible from other containers running on the same docker host as the container that launched with this docker image - Correct. The EXPOSE instruction makes the port available for inter-container communication. D. Local port 8080 of the container that launched with this docker image is accessible to external clients - Incorrect. The EXPOSE instruction does not publish the port to external clients.

References:

Dockerfile reference - EXPOSE

pyATS (Python Automation Test System) is a tool developed by Cisco that allows for comprehensive testing of network configurations and automation scripts. It is designed to validate and test changes before they are applied to the production environment, ensuring reliability and reducing the risk of errors.

References:

Cisco DevNet Associate Study Guide: Network Test Automation (Chapter 6, Section: Introduction to pyATS and Its Use Cases).

Organizing code into modules helps manage large and complex systems by breaking them down into smaller, more manageable pieces. Each module can be developed, tested, and maintained independently, which simplifies the overall development and maintenance process.

The bash script shown in the exhibit automates the process of downloading, extracting, compiling, installing, and configuring the Cisco DevNet application. It also enables and starts the application automatically.

Download and Extract: The script uses curl to download a tar.gz file and then extracts it using tar -zxf.

Compilation and Installation: The ./configure && make && make install commands compile and install the application.

Enabling and Starting the Service: The systemctl enable devnet and systemctl start devnet commands ensure the application starts automatically on system boot and starts it immediately.

Option B correctly describes the workflow as it includes compilation, installation, configuration, and automatic startup of the application.

The DevNet Automation Exchange is designed to provide users with easy-to-consume use cases for network automation across various skill levels. It includes resources for beginner, intermediate, and advanced users to help them accelerate the adoption of automation technologies.

DevNet Automation Exchange: This site provides curated content and solutions for network automation. It includes code samples, learning labs, and use cases that cater to different skill levels.

User-Friendly Resources: The platform is designed to help users find relevant information quickly and easily, regardless of their experience level.

Option B is the correct answer because it specifically addresses the need for a single site that offers a variety of resources for different skill levels in network automation.

Refactoring is done during test-driven development (TDD) to improve the maintainability and readability of the code. After writing tests and ensuring that the code passes those tests, developers refactor to clean up the code, making it more efficient and easier to understand without changing its functionality.

A. to enable larger objects and longer methods - Incorrect. Refactoring aims to simplify and streamline code, not make it larger or more complex. B. to improve maintainability and readability - Correct. Refactoring makes the code easier to maintain and understand. C. to ensure that the previous uses of the objects are explained - Incorrect. This is not the purpose of refactoring. D. to ensure the duplication of essential code - Incorrect. Refactoring seeks to reduce code duplication, not ensure it.

References:

Test-Driven Development by Example

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 main purpose of a code review is to identify and review errors, ensuring code quality and adherence to coding standards. It involves evaluating the code for bugs, security vulnerabilities, and performance issues, and discussing potential improvements with the team. This collaborative process helps catch errors early, fosters knowledge sharing, and improves the overall quality of the codebase.

References:

Cisco DevNet Associate Study Guide: Code Review Best Practices (Chapter 6, Section: Importance of Code Reviews).

The error in the Python code is due to the requests library not being defined, which typically means it hasn't been installed. To resolve this issue, the requests library needs to be installed using the pip install requests command. This will add the necessary module to the Python environment, allowing the code to execute correctly.

The agile process allows for incremental delivery of features, meaning new functionalities can be added or existing ones updated in small, manageable increments. This is in contrast to the waterfall model, where all phases are completed before the product is delivered. Agile enables continuous improvement and adaptation to changing requirements throughout the development process.

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.

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

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

Ansible is a configuration management tool that has agentless capabilities. It uses SSH for communication and does not require any agent software to be installed on the managed nodes. This simplifies management and reduces overhead.

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).

In NETCONF, the operation retrieves all or part of a configuration and state data from the running datastore. The operation retrieves configuration data from a specific configuration datastore (e.g., running, startup). These operations correspond to the RESTCONF GET operation, which is used to retrieve configuration and state data from a network device. This mapping between NETCONF and RESTCONF operations is described in detail in the RFC 6241 for NETCONF and RFC 8040 for RESTCONF.

When you execute the command git clone ssh://john@example.com/path/to/my-project_git, the git clone command is used to create a local copy of a remote repository. In this case, it is accessing the repository over SSH (Secure Shell). The URL ssh://john@example.com/path/to/my-project_git specifies the location of the remote repository.

git clone is a Git command that creates a copy of an existing repository in a new directory.

The local copy will contain all the history and branches of the original repository.

The repository will be cloned into a directory named after the remote repository, which in this case would be "my-project".

The Python function shown in the exhibit performs the following operations:

It defines a function get_result().

Inside the function, it sets the url variable to the Cisco DNA Center (DNAC) API endpoint for authentication tokens.

It makes a POST request to the specified URL with HTTP Basic Authentication using the credentials DNAC_USER and DNAC_PASSWORD.

The response from the POST request is expected to be in JSON format.

It extracts the value associated with the key 'Token' from the JSON response.

Finally, it returns this token.

This function's purpose is to obtain and return an authorization token from the Cisco DNA Center API, which can be used for subsequent API requests.

The issue shown in the sequence diagram is an HTTP 401 Unauthorized response. This suggests that the authentication credentials provided are incorrect or improperly formatted. The correct format for the credentials in a cURL command should be without quotes around the username and password. Hence, changing -u 'cisco

' to -u cisco

resolves the issue.

1 – D, 2 – B, 3 – C, 4 – E, 5 – A

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

Virtual machines (VMs) run directly on a hypervisor, which abstracts and manages the underlying hardware resources.

Hypervisor: A hypervisor, also known as a Virtual Machine Monitor (VMM), allows multiple VMs to run on a single physical machine by providing an abstraction layer between the VMs and the hardware.

VMs: Each VM operates as a separate entity with its own operating system and applications, isolated from other VMs.

A default gateway serves as an access point or IP router that a networked computer uses to send information to a computer in another network or the internet. It is essentially the forwarding node that routes traffic from a local network to other networks. When an IP packet's destination is not within the local network and no specific route is defined in the routing table, the packet is sent to the default gateway.

The CNAME (Canonical Name) record is used in DNS to create an alias that points to another domain name. This domain name then resolves to an IP address. For instance, if you have a CNAME record for www.example.com pointing to example.com, accessing www.example.com will direct you to example.com, which will ultimately resolve to the IP address of example.com. This is particularly useful for pointing multiple domain names to the same IP address, allowing easier maintenance and updates. References for this can be found in Cisco's DNS documentation.

The Model-View-Controller (MVC) design pattern is a software architectural pattern that separates an application into three main logical components: the Model, the View, and the Controller. Each of these components is built to handle specific development aspects of an application.

Advantages of MVC:

Allows for multiple views of the same model (Option B):

In the MVC architecture, the Model component represents the data and the business logic of the application. It is independent of the user interface. This separation allows the application to have multiple views that can present data in different ways without requiring changes to the underlying data model. For example, the same data can be displayed in a web application, a mobile app, or even a command-line interface, all using the same model.

Separates responsibilities of the code, which makes future modifications easier (Option E):

By separating the application into distinct components (Model, View, Controller), MVC clearly defines the responsibilities of each part. The Model is responsible for data management, the View for the user interface, and the Controller for handling user input and interactions. This separation of concerns makes the application easier to maintain and modify. Future changes can be made to one component without significantly affecting the others. For instance, changes to the user interface can be made in the View without altering the underlying data model or the business logic in the Model.

Other Considerations:

Simplifies network automation (Option A): While MVC can be used to create applications that interact with network automation tools, simplifying network automation is not a direct advantage of the MVC pattern itself.

Makes code easier to deploy using CI/CD pipelines (Option C): CI/CD pipelines benefit from modular and well-structured code, but the MVC pattern specifically addresses the organization of code and separation of concerns, rather than deployment processes.

Reduces need for error handling (Option D): Error handling is an essential aspect of any application and is not inherently reduced by the use of MVC. Instead, MVC helps in organizing the code in a way that might make error handling more systematic, but it does not directly reduce the need for it.

The separation of concerns and the ability to have multiple views of the same model are core advantages of using the MVC pattern, making it a powerful design approach for creating scalable and maintainable applications.

References:

Model-View-Controller (MVC) Architecture

Cisco DevNet Developer Resources

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

YANG (Yet Another Next Generation) is a data modeling language used to model configuration and state data manipulated by the NETCONF protocol. Here are two advantages of YANG-based approaches for infrastructure automation:

Multi-platform vendor abstraction (Option B):

YANG provides a standardized way to model configuration and state data, enabling multi-platform vendor abstraction. This means that network engineers can write configurations and management scripts that work across different network devices from different vendors, as long as they adhere to the YANG model. This reduces the complexity and increases the interoperability in multi-vendor environments.

Designed to reflect networking concepts (Option C):

YANG is specifically designed to reflect networking concepts and constructs, making it intuitive and effective for defining network configurations and states. The hierarchical structure of YANG models aligns well with the structure of network configurations, allowing for precise and clear definitions of network elements and their relationships.

References:

Cisco YANG Overview

IETF YANG

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.

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

The Python script provided makes a GET request to the Cisco DNA Center API to retrieve a list of network devices. The script processes the JSON response, iterates over each item in the response, and prints the hostname and management IP address of each device.

The process_devices function constructs the API URL using the dnac['host'].

It sends an HTTP GET request with the necessary headers, including the authentication token.

The response is parsed as JSON and stored in the data variable.

The script then loops through the data['response'] list, printing the hostname and managementIpAddress for each device.

Solution below

To list the networks in a Meraki organization using the Meraki API, you need to construct a proper cURL command. The command must include the URL endpoint specific to the Meraki organization ID and the required API key for authentication. The correct cURL command to list networks in the organization with ID 384279060 is:

curl -X GET -L \

--url https://api.meraki.com/api/v0/organizations/384279060/networks \

-H 'X-Cisco-Meraki-API-Key: $meraki_api_key'

Here:

-X GET: Specifies the request method as GET.

-L: Follows any redirects.

--url: Specifies the API endpoint URL.

-H 'X-Cisco-Meraki-API-Key: $meraki_api_key': Adds the API key header for authentication.

References: Cisco DevNet Associate Certification Guide, Chapter on Cisco Meraki APIs and REST API calls.

In REST architecture, the stateless constraint indicates that no client context should be stored on the server between requests. Each request from the client to the server must contain all the information needed to understand and process the request.

Stateless: Ensures that each request is independent and contains all necessary information.

Uniform interface: Defines a standard way of interacting with resources.

Cacheable: Responses must define whether they are cacheable to improve performance.

Client-server: Separates the client and server roles.

1 – B, 2 – E, 3 - F

A – E, B – D, C – B, D – C, E – A, F – F

The provided Ansible playbook is designed to connect to an IOS router and execute the "show run" command to retrieve the current running configuration. The configuration is then registered in a variable called config. The next task copies the output stored in the config variable to a file in a specified directory on the local machine. The file is named based on the router's hostname.

Here are the steps:

Define the hosts: The playbook targets the {{ router }} group or host.

Gather facts: Enabled with gather_facts: true to collect useful information about the target devices.

Connection type: Local, meaning the playbook runs on the local machine where Ansible is invoked.

Task 1 - ios_command:

Executes the "show run" command.

Uses the provided router credentials.

Registers the command output to the config variable.

Task 2 - copy:

Takes the first element from config.stdout (the output of the "show run" command).

Copies this content to a file in /etc/ansible/configs/, naming the file command_{{ router_hostname }}.txt.

A router is a network device that routes traffic between different broadcast domains and subnets. Routers operate at the network layer (Layer 3) of the OSI model and use IP addresses to make forwarding decisions. They are responsible for determining the best path for data packets to travel across interconnected networks, ensuring that traffic is correctly directed from one broadcast domain to another.

References:

Cisco Router Basics

Broadcast Domains and Routers

=========================

When authenticating a RESTCONF API session with a router running Cisco IOS XE software, basic authentication is commonly used. Basic authentication involves sending the username and password in the HTTP header encoded in base64 format. This method is straightforward and widely supported, though it is less secure compared to token-based authentication and should be used with HTTPS to ensure the credentials are encrypted in transit.

The HTTP status code 400 (Bad Request) is used by a REST API to indicate that the server cannot or will not process the request due to something that is perceived to be a client error (e.g., malformed request syntax, invalid request message framing, or deceptive request routing).

In the exhibit, the unified diff output shows changes made to the single_request_timeout method in a Python script. The modifications include:

Removing the assert statement that checks if the value is None or greater than 0.

Adding a raise ValueError statement to ensure that the single_request_timeout must be a positive integer if the value is not None.

These changes can be seen in the sections labeled with @@ -160,11 +160,12 @@ indicating the lines in the original and modified files. The lines starting with - indicate removed lines, and those starting with + indicate added lines. This type of change is typical in code updates to improve validation and error handling.

In this scenario, the developer is retrieving a large number of messages from a Cisco Webex space, and the server only sends a subset of the total messages at a time. This is an example of pagination, where the data is split into multiple pages or chunks, and the client must make additional requests to retrieve the next set of data.

Pagination: This is a common API constraint used to handle large datasets by breaking them into manageable pages.

Subsequent Requests: The client needs to send subsequent requests to get the remaining data.

Option C is correct as it describes the constraint where data is divided into multiple pages and requires additional requests to retrieve all data.

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.

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

Deploying applications in a public cloud provides several advantages, especially for developers dealing with temporary data processing and secure storage:

Ease in Infrastructure Management: Public cloud services offer managed infrastructure, which significantly reduces the operational burden on developers. They do not need to worry about hardware maintenance, scaling, or other infrastructure-related tasks.

Scalability: Public clouds provide scalable resources, allowing developers to adjust their infrastructure needs dynamically as per the workload requirements.

Cost-Effectiveness: Public clouds often operate on a pay-as-you-go model, which can be more cost-effective for temporary or variable workloads.

References:

Cisco DevNet Associate Certification Guide

General public cloud service provider documentation (e.g., AWS, Azure, Google Cloud)

The Dynamic Host Configuration Protocol (DHCP) is responsible for automatically assigning IP addresses to devices on a network. When a device connects to the network, it sends a broadcast request for an IP address, and a DHCP server responds with an IP address, subnet mask, default gateway, and DNS server information. This process simplifies network administration by automating IP address assignment and ensuring that devices have unique IP addresses without manual configuration.

References:

Cisco DHCP Overview

RFC 2131: DHCP

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.

In the given Dockerfile, the WORKDIR /app command sets the working directory for any subsequent commands to /app. This means that any commands following this line will be executed within the /app directory inside the Docker container. The COPY . . command copies the contents of the current directory on the host machine to the /app directory in the container. Finally, the CMD ["node", "source/server.js"] command specifies the command to run when the container starts, which in this case is node source/server.js.

References:

Dockerfile Reference - WORKDIR

To download and execute an Apache web server container in Docker, you need to perform two steps: pulling the image and running the container with the appropriate port bindings.

docker pull httpd - This command downloads the Apache HTTP server image from the Docker repository. "httpd" is the official name for the Apache HTTP server image on Docker Hub.

docker run -p 8080:80 httpd - This command runs a new container from the "httpd" image, mapping port 8080 on the host to port 80 in the container. This allows you to access the web server running in the container via port 8080 on your host machine.

References:

Docker Documentation - docker pull

Docker Documentation - docker run

Cisco DevNet Associate Certification Guide

In the provided NETCONF response:

The OSPF configuration is defined by the ietf-ospf module.

The element is structured as a list, allowing for multiple routing protocol entries.

In the provided Python code, the API_PASSWORD is retrieved from the environment variable API_PASSWORD. To set this environment variable in a Bash shell, the correct command to use is export. This command sets the environment variable for the current shell session and any child processes.

Bash Command: export API_PASSWORD=Cisco123!

This command ensures that the environment variable API_PASSWORD is set to "Cisco123!" and can be accessed by the Python script.

References:

Bash export Command

Cisco DevNet Associate Certification Guide

REST APIs are designed around resources that are identified by URLs. Operations are performed on these resources using standard HTTP methods like GET, POST, PUT, and DELETE. In contrast, RPC (Remote Procedure Call) APIs are designed around actions or operations, where the focus is on invoking methods or functions rather than manipulating resources.

For a web-based application that captures and processes credit card information, it is essential to ensure the security of the private customer data. Enabling the encryption of network traffic, typically through TLS (Transport Layer Security), protects sensitive information by encrypting data transmitted between the client and server. This prevents unauthorized access and ensures data integrity and confidentiality during the transaction process.

When writing applications, using classes over functions offers several benefits, including improved readability and better code organization. Here are the detailed explanations for these two benefits:

Improved Readability (A):

Classes allow for encapsulation, which means grouping related data and functions (methods) together. This makes the code more readable and easier to understand because the related functionality is bundled in a single, self-contained unit.

Object-Oriented Programming (OOP) principles such as inheritance and polymorphism further enhance readability by reducing code duplication and promoting code reuse.

Code Organization (E):

Classes provide a clear structure for organizing code. They help in logically grouping related functionalities, which enhances the modularity of the application. This organization makes it easier to manage and maintain the codebase, especially as the application grows in complexity.

By using classes, developers can create blueprints for objects, making it easier to implement and manage complex systems with multiple interconnected components.

Classes are fundamental to Object-Oriented Programming, which is a paradigm that many modern programming languages, including Python and Java, are built around. While functions are essential for specific tasks and operations, classes provide a higher level of abstraction and organization.

References:

Cisco DevNet Associate Certification Guide

Python Documentation - Classes

Java Documentation - Classes and Objects

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

RESTCONF is a protocol used to access data defined in YANG using standard HTTP methods. However, it does not support distributed transactions, which is a requirement in this scenario.

RESTCONF: Supports YANG data models, XML encoding, and can be used in environments with software redundancy.

Distributed Transactions: RESTCONF does not support distributed transactions, which require coordination of a transaction across multiple network devices or components.

Option C is correct as the requirement for distributed transactions prevents the use of RESTCONF.

DNS (Domain Name System) is the technology responsible for resolving a host name to an IP address. It translates domain names, which are easier for humans to remember, into IP addresses that are used by network devices to locate and communicate with each other over the internet. When a user types a domain name into a web browser, the DNS server maps it to the corresponding IP address so the browser can load the desired web page.

The provided Bash script performs the following steps:

Adds a new user with useradd.

Adds a new group with groupadd.

Creates a directory /opt/scripts.

Copies all Python scripts (*.py) to the /opt/scripts directory.

Changes to the /opt/scripts directory.

Lists the Python scripts and processes each script in a loop.

Within the loop, the script:

Appends the script name to a file content.txt.

Assigns execution privileges to the script (chmod u+x).

Changes the ownership of the script to the newly created user and group (chown $1:$2).

This workflow automates the process of setting execution permissions for the owner (the newly created user) and assigning the user and group ownership to the scripts. It also stores the script names in content.txt.

References:

Cisco DevNet Associate Certification Guide

Bash Scripting Documentation

The Cisco Finesse platform is designed to provide a customizable interface for contact center agents and supervisors. One of its key characteristics is the ability to invoke services based on network-triggered events, allowing for dynamic and responsive workflows within the contact center environment.

The EXPOSE instruction in a Dockerfile informs Docker that the container listens on the specified network ports at runtime.

EXPOSE Instruction: It does not publish the port but indicates to Docker that the application inside the container uses this port.

Listening Port: The Docker container will be configured to listen on port 5000 using EXPOSE 5000.

References:

Dockerfile Reference: Dockerfile EXPOSE

The Python script provided is designed to make a POST request to a REST API to create a new task in a to-do list application. Here's a step-by-step explanation of the script:

Import the requests library to handle HTTP requests.

Define the task dictionary with summary and description.

Use the requests.post method to send a POST request to the specified URL, passing the task data as JSON and setting the appropriate Content-Type header.

Check if the response status code is not 201 (which indicates successful creation). If it's not, raise an ApiError with the status code.

Print the created task's ID from the JSON response.

The provided code options are:

requests: the library used for making HTTP requests.

status_code: used to check the HTTP response status.

Content-Type: a header specifying the media type of the resource.

raise: used to raise an exception if the status code is not as expected.

return is not used in this context.

References:

Cisco DevNet Associate Certification Guide

Python Requests Library Documentation

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

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

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.

The exhibit shows an architecture where each application runs in its own isolated environment with its own OS. This setup is typical of virtual machines (VMs), where multiple VMs can run on a single physical server managed by a hypervisor.

Isolation: VMs provide complete isolation between applications, including independent operating systems.

Resource Allocation: Resources such as CPU, memory, and storage can be allocated based on deployment requirements.

Option B is correct as the type of deployment used is virtual machines.

To build a Docker image using the current folder and a specified Dockerfile, and then tag the image with a specific name for the local repository, the following command is used:

docker build: This command builds a Docker image from a Dockerfile.

-t cust321453857-rep: The -t option tags the resulting image with the specified name (cust321453857-rep).

-f Dockerfile: The -f option specifies the Dockerfile to use for building the image.

Command:

docker build -t cust321453857-rep -f Dockerfile .

References:

Docker Build Command: Docker Build

The subnet mask is used to determine the network and host portions of an IP address. It helps in defining the size of the subnet and the range of IP addresses within that subnet.

Subnet Portion: The subnet mask identifies which part of the IP address refers to the network (subnet) portion.

Host Portion: The remaining part of the IP address after applying the subnet mask identifies the specific host within the subnet.

Options A and D are correct as they capture the details about the subnet and host portions of an IP address.

Implementing common data structures when working with APIs in remote systems has multiple benefits:

Enforces standardized data structures: This ensures consistency and interoperability across different systems and APIs, making it easier to integrate and communicate between various components.

Leverages code that is easily managed and reused: Standardized data structures lead to more maintainable and reusable code. Developers can build upon existing frameworks and libraries without having to rewrite data handling logic for each new API.

References: Cisco DevNet Data Structures

V

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 exhibit shows the router configuration for NAT (Network Address Translation). To allow traffic from the security cameras to access the Internet, the access list needs to include a permit statement for the 192.168.10.0/24 subnet.

Access List Configuration: The access list (ACL) should permit traffic from the security camera VLAN (192.168.10.0/24).

NAT Configuration: The NAT configuration uses an ACL to determine which internal IP addresses are translated to the public IP address pool.

Missing Permit Statement: Without a specific permit statement for the 192.168.10.0/24 subnet, the router does not translate the IP addresses from this subnet, resulting in a lack of Internet access for the security cameras.

References:

Cisco NAT Configuration Guide: NAT Configuration

The pip freeze command is used to output installed packages in the current environment and their versions. The > operator redirects this output to a file, in this case, requirements.txt.

pip freeze: Outputs the list of installed packages and their versions.

Redirection: The > operator is used to redirect the output to a file.

Option B is correct as it uses the > operator to redirect the output of pip freeze to requirements.txt.

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

import requests

data = {

"id": 11,

"summary": "Request summary"

}

response = requests.post('https://todolist.example.com/tasks/ ', json=data)

if response.status_code != 201:

raise ApiError('POST /tasks/ {}'.format(response.status_code))

for item in response.json():

print('{} {}'.format(item['id'], item['summary']))

Importing the Requests Library:

The requests library is used to make HTTP requests in Python. It is a popular third-party library that simplifies interactions with web APIs.

Creating the Data Payload:

The data dictionary contains the information to be sent in the body of the POST request. It includes an id and a summary.

Making the POST Request:

The requests.post method is used to send a POST request to the specified URL (https://todolist.example.com/tasks/). The json=data parameter automatically converts the data dictionary to a JSON-formatted string and sets the appropriate headers.

Checking the Response Status Code:

The script checks if the status_code of the response is not equal to 201. A status code of 201 indicates that the request was successful and a resource was created.

If the status code is not 201, an ApiError is raised with a message that includes the status code.

Processing the JSON Response:

The response.json() method is used to parse the JSON response into a Python dictionary.

The script iterates over the items in the JSON response and prints the id and summary of each item.

References:

Cisco DevNet Associate Certification Guide, Sections on interacting with REST APIs using Python

Official documentation for the Requests library: Requests: HTTP for Humans

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 applicationhttps://www.dumpspedia.com/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'.

synchronous: Code execution must wait for an API call to return before continuing.

asynchronous: Code execution does not need to wait for an API call to return before continuing.

REST: Data is called indirectly using generic HTTP methods such as GET, POST, PUT, and DELETE.

RPC: Calls to request a service from a remote server must execute the same way as a request to the local system.

Comprehensive Detailed Step by Step Explanation with References

Synchronous:

Explanation: In a synchronous API call, the client must wait for the server to process the request and return a response before it can proceed with further execution.

Mapping: "Code execution must wait for an API call to return before continuing."

Asynchronous:

Explanation: In an asynchronous API call, the client can continue processing other tasks while waiting for the server to respond. This improves the efficiency and responsiveness of the application.

Mapping: "Code execution does not need to wait for an API call to return before continuing."

REST (Representational State Transfer):

Explanation: REST is an architectural style for designing networked applications. It relies on a stateless, client-server communication protocol, typically HTTP. RESTful APIs use standard HTTP methods (GET, POST, PUT, DELETE) to perform operations on resources.

Mapping: "Data is called indirectly using generic HTTP methods such as GET, POST, PUT, and DELETE."

RPC (Remote Procedure Call):

Explanation: RPC is a protocol that one program can use to request a service from a program located on another computer in a network. The calls are made in the same way as a local function call.

Mapping: "Calls to request a service from a remote server must execute the same way as a request to the local system."

References:

Cisco DevNet Associate Certification Guide, Sections on API styles and their characteristics

Official Cisco documentation on RESTful and RPC APIs

General programming resources on synchronous vs. asynchronous API calls

Therefore, the correct mapping is:

synchronous → "Code execution must wait for an API call to return before continuing."

asynchronous → "Code execution does not need to wait for an API call to return before continuing."

REST → "Data is called indirectly using generic HTTP methods such as GET, POST, PUT, and DELETE."

RPC → "Calls to request a service from a remote server must execute the same way as a request to the local system."

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.

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.

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 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

The packet capture shows that the packets are arriving at Server B and that the server responds, indicating that Server B is reachable and the API service is running. However, since the developer cannot access the API, the most likely cause is that the return traffic on port 443 (HTTPS) is being blocked on the incoming interface of Firewall B. This means that although Server B is responding, the responses are not getting back to the developer's client because they are being blocked by the firewall.

An Ethernet switch operates at the Data Link layer (Layer 2) of the OSI model. Its primary function is to forward frames between devices based on their MAC (Media Access Control) addresses. When a frame arrives at the switch, the switch reads the destination MAC address and forwards the frame to the appropriate port that connects to the device with that MAC address.

MAC Address Table: Switches maintain a MAC address table that maps each MAC address to a specific port. This table is built dynamically as the switch learns the MAC addresses of devices connected to its ports.

Frame Switching: By using the MAC address table, the switch can efficiently switch frames only to the destination port, which reduces unnecessary traffic on other ports and improves network performance.

References:

Cisco DevNet Associate Certification Guide

Cisco Ethernet Switch Operation

An HTTP 502 Bad Gateway error indicates that the server acting as a gateway or proxy received an invalid response from the upstream server. This suggests there may be an issue with the configuration or availability of the server behind the load balancer.

HTTP 502 Error: This error occurs when the load balancer or gateway receives an invalid response from the backend server.

Server Configuration: The issue is likely due to misconfiguration or problems with the backend server that needs to be resolved.

Option A is correct as it identifies that the issue lies with the server configuration behind the load balancer.

Model-driven programmability refers to the use of a consistent data model to manage and automate network devices. Key capabilities include:

Single Data Model Across the Network: Ensures uniformity and consistency in how data is represented and managed across different network devices and platforms.

Automation and Scalability: Facilitates automated network configurations and operations, enabling scalability.

Interoperability: Using standardized models (like YANG) allows for interoperability between different network devices and management tools.

Abstracted API Interfaces: Provides abstracted and consistent APIs that can be used across multiple devices, reducing the complexity of network automation scripts.

References:

Cisco Model-Driven Programmability