200-901 Practice Test 5 — 25 Questions

Question 1

You are a network automation engineer using the Cisco DNA Center REST API to retrieve health scores for all sites in your network. You call the 'GET /dna/intent/api/v1/site-health' endpoint with parameters to filter by time range. The response returns only the first 20 sites out of a total of 150 sites. You notice that the response includes a 'totalRecords' field showing 150, but only 20 objects are in the 'response' array. You recall that the API documentation mentions pagination support. To avoid manually looping through all pages, you want to implement a robust solution that efficiently retrieves all site health data. Which approach should you take?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Use the 'nextPageUri' field provided in the response to iterate through all pages until no more pages are available.. The Cisco DNA Center REST API implements pagination using a 'nextPageUri' field in the response, which provides the direct URL to the next page of results. By following this field iteratively until it is null or absent, you can efficiently retrieve all 150 site health records without manually constructing pagination parameters or looping through page numbers, ensuring a robust and maintainable solution.

Answer

Change the endpoint to 'GET /dna/intent/api/v1/network-device' which returns all devices without pagination.

Answer

Export the site health data using the 'POST /dna/intent/api/v1/site-health/export' endpoint.

Answer

Increase the 'pageSize' parameter to 150 to retrieve all records in a single request.

Question 2

Which THREE of the following are common design patterns for microservices? (Choose three.)

Accepted Answer

Circuit Breaker. The Circuit Breaker pattern (B) is a common microservices design pattern that prevents cascading failures by monitoring for failures and opening a circuit to stop requests to a failing service, allowing it to recover. It is widely implemented in frameworks like Netflix Hystrix or Resilience4j, where states (closed, open, half-open) control request flow and timeout thresholds.

Answer

Chain of Responsibility

Answer

Singleton

Question 3

When designing a REST API endpoint to update a network device's configuration, which HTTP method should be used?

Accepted Answer

PUT. PUT is the correct HTTP method for updating a network device's configuration because it is idempotent and replaces the entire resource at the specified URI. In RESTful design, PUT is used to update or create a resource when the client sends a full representation of the resource, which aligns with replacing the entire device configuration.

Answer

POST

Answer

DELETE

Answer

PATCH

Question 4

A developer needs to ensure that microservice A can securely communicate with microservice B over HTTPS within a Kubernetes cluster. What is the simplest approach?

Accepted Answer

Create a Kubernetes Service of type ClusterIP for microservice B and configure microservice A to use HTTPS with the service DNS name.. Using a ClusterIP Service for microservice B provides a stable DNS name within the cluster, allowing microservice A to communicate over HTTPS without exposing the service externally. This approach leverages Kubernetes' internal service discovery and can be paired with a service mesh or mutual TLS (mTLS) for secure communication, meeting the requirement for simplicity and security.

Answer

Use a Kubernetes Ingress resource with TLS termination for microservice B.

Answer

Expose microservice B via a LoadBalancer Service and use HTTPS from microservice A.

Answer

Connect directly using the pod IP of microservice B over HTTP.

Question 5

A developer is designing a microservices architecture for a network monitoring application. Which of the following is a key advantage of microservices over a monolithic architecture?

Accepted Answer

Independent deployability and scalability of services. Microservices architecture enables each service to be deployed, updated, and scaled independently without affecting other services. This is a key advantage over monolithic architectures, where any change requires rebuilding and redeploying the entire application. For a network monitoring application, independent scalability allows resource-intensive services (e.g., packet capture) to scale separately from lightweight services (e.g., alerting).

Answer

Lower latency due to in-process communication

Answer

Easier to maintain as a single codebase

Answer

Simpler inter-service communication

Question 6

Refer to the exhibit. A network engineer runs a script that queries the Cisco DNA Center site health API. The response shows Branch1 with a healthScore of 10. What is the most likely action to improve Branch1's health?

Accepted Answer

Investigate the network devices and connectivity at Branch1.. A healthScore of 10 on a scale of 0–100 indicates severe degradation, typically caused by network device failures, link flaps, or connectivity loss. Investigating the network devices and connectivity at Branch1 is the correct first step to identify and resolve the root cause, such as a down switch or a routing issue.

Answer

Increase the number of clients at Branch1.

Answer

Check the API authentication token.

Answer

Use a different API version.

Question 7

A network engineer is writing a Python script to interact with Cisco DNA Center. After successfully authenticating and receiving a token, what header must be included in subsequent API requests?

Accepted Answer

In the Authorization header as Bearer. Cisco DNA Center uses token-based authentication following the OAuth 2.0 framework. After obtaining a token via the /dna/system/api/v1/auth/token endpoint, the token must be included in the Authorization header using the Bearer scheme (e.g., 'Authorization: Bearer <token>') for all subsequent API requests to prove the client's identity and authorization.

Answer

In a custom header

Answer

In the URL query string

Answer

In the request body

Question 8

A Python script sends the above REST API request to a Cisco Catalyst 9000 switch running IOS XE. The response is a 400 Bad Request. Which field is most likely missing from the JSON payload?

Accepted Answer

interface. The REST API request is targeting the creation of a network interface on a Cisco Catalyst 9000 switch running IOS XE. The 400 Bad Request indicates a missing required field in the JSON payload. According to the Cisco IOS XE REST API documentation for the `/api/v1/interface` endpoint, the `interface` field (which specifies the interface name, e.g., 'GigabitEthernet1/0/1') is mandatory when creating a new interface. Without it, the API cannot determine which interface to configure, resulting in a 400 error.

Answer

vlanId

Answer

description

Answer

name

Question 9

Which TWO statements about REST API design best practices are true? (Choose two.)

Accepted Answer

Use nouns for resource endpoints, e.g., /devices instead of /getDevices. RESTful APIs use nouns to represent resources (e.g., /devices) rather than verbs (e.g., /getDevices). This aligns with the uniform interface constraint of REST, where the HTTP method (GET, POST, etc.) defines the action, and the URI identifies the resource. Using nouns keeps the API intuitive, consistent, and scalable.

Answer

Avoid API versioning to keep the API simple

Answer

Include the HTTP method in the URI path, e.g., /getDevices

Answer

Always use file-based transfer for large payloads

Question 10

A developer is designing an API that needs to support rate limiting per API key. The application is deployed on multiple instances. Which approach ensures consistent rate limiting across all instances?

Accepted Answer

Use a distributed cache like Redis. A distributed cache like Redis provides a shared, atomic counter that all application instances can read and increment, ensuring consistent rate limiting across a multi-instance deployment. Redis supports atomic operations like INCR and EXPIRE, which are essential for implementing sliding window or token bucket algorithms without race conditions.

Answer

Use a local in-memory counter

Answer

Use a file-based lock

Answer

Use environment variables

Question 11

Which THREE of the following are characteristics of the UDP protocol?

Accepted Answer

Used by DNS and DHCP. UDP is a connectionless transport layer protocol that provides minimal overhead, making it ideal for applications like DNS and DHCP that require fast, lightweight communication. DNS uses UDP for queries (port 53) and DHCP uses UDP for client-server exchanges (ports 67/68) because they can tolerate occasional packet loss and benefit from the reduced latency.

Answer

Connection-oriented

Answer

Reliable delivery

Question 12

A developer is designing a REST API that requires pagination. Which two pagination methods are commonly used? (Choose two.)

Accepted Answer

Offset/limit pagination. Offset/limit (page number/size) and cursor-based (use a token or cursor to navigate) are common. Link headers (RFC 5988) are also used but are not a pagination method themselves; they convey links. B-tree and hash-based are not typical.

Answer

B-tree pagination

Answer

Link header pagination

Answer

Hash-based pagination

Question 13

Drag and drop the steps to configure a Cisco IOS device for NETCONF access into the correct order.

Accepted Answer

Configure SSH, then create a local user, then enable NETCONF, then verify. NETCONF requires enabling the service, SSH configuration, user creation, and verification.

Answer

Enable NETCONF, then configure SSH, then create a local user, then verify

Answer

Create a local user, then enable NETCONF, then configure SSH, then verify

Answer

Configure SSH, then create a local user, then verify, then enable NETCONF

Question 14

A network automation engineer is tasked with creating a Python script to automatically back up the running configuration of all IOS XE devices in a data center using the Cisco IOS XE REST API. The engineer has credentials for each device and knows the IP addresses. The script uses the requests library and sends a GET request to https://<device-ip>/restconf/data/Cisco-IOS-XE-native:native?content=config. The script runs successfully for some devices but fails with a 401 Unauthorized error for others. The engineer confirms the credentials are correct and the devices are reachable. The working devices are running IOS XE 16.9, while the failing ones are running IOS XE 16.6. The engineer checks the API documentation and finds that RESTCONF is enabled on all devices. However, the engineer notices that the failing devices require a different authentication method. What should the engineer do to fix the authentication for the IOS XE 16.6 devices?

Accepted Answer

Modify the script to use HTTP Basic Authentication and disable CSRF check on the device.. IOS XE 16.6 requires HTTP Basic Authentication with the 'Authorization' header, and the RESTCONF API on these older versions also requires disabling the CSRF (Cross-Site Request Forgery) check. The engineer must modify the script to include the 'requests.auth.HTTPBasicAuth' and set the 'X-CSRF-Token' header to 'false' or disable CSRF on the device. This resolves the 401 error while still using RESTCONF.

Answer

Switch from HTTPS to HTTP for the failing devices.

Answer

Use the NETCONF protocol instead of RESTCONF for all devices.

Answer

Change the URL to use the Cisco IOS XE CLI-based API instead of RESTCONF.

Question 15

Refer to the exhibit. The Docker image built from this Dockerfile is larger than expected. Which optimization should be recommended?

Accepted Answer

Use a multi-stage build.. Multi-stage builds allow you to use multiple FROM statements in your Dockerfile. You can compile or install dependencies in an intermediate stage using a full-featured base image, then copy only the necessary artifacts (e.g., compiled code, libraries) into a final, minimal runtime image. This dramatically reduces the final image size by discarding build tools, temporary files, and unnecessary layers from the earlier stages.

Answer

Use a smaller base image like python:3.9-alpine.

Answer

Combine RUN and COPY layers to reduce layers.

Answer

Remove the EXPOSE instruction.

Question 16

A DevOps engineer wants to automate the configuration of network devices using Ansible. Which file format is commonly used for Ansible playbooks?

Accepted Answer

YAML. Ansible playbooks are written in YAML (YAML Ain't Markup Language) because YAML is human-readable, supports complex data structures like lists and dictionaries, and is designed for configuration files. YAML's indentation-based syntax aligns with Ansible's declarative automation model, making it the default and recommended format for defining tasks, variables, and handlers in playbooks.

Answer

INI

Answer

XML

Answer

JSON

Question 17

A Python script using the Cisco Meraki SDK fails with 'APIError: 429 Too Many Requests'. What action should the developer take?

Accepted Answer

Add a retry mechanism with exponential backoff. The HTTP 429 status code indicates rate limiting has been exceeded. The Meraki API enforces rate limits to protect its infrastructure, and the SDK's built-in retry mechanism with exponential backoff is the correct way to handle this, as it automatically waits increasing intervals between retries, respecting the Retry-After header if present.

Answer

Increase the timeout value

Answer

Change the HTTP method to POST

Answer

Use a different API key

Question 18

A developer is deploying a microservice to a Kubernetes cluster. The application needs to read a database password securely without hardcoding it in the image. Which Kubernetes resource should be used?

Accepted Answer

Secret. (Secret) is correct because Kubernetes Secrets are specifically designed to store sensitive data such as database passwords, API keys, and certificates. They can be mounted as files or injected as environment variables into pods, ensuring the password is never hardcoded in the container image. Secrets are base64-encoded and can be encrypted at rest using etcd encryption or external KMS providers, providing a secure mechanism for managing credentials.

Answer

ConfigMap

Answer

ServiceAccount

Answer

PersistentVolume

Question 19

A developer is working on a Python script that performs CRUD operations on devices via a REST API. Which HTTP method should be used to update an existing device's configuration partially?

Accepted Answer

PATCH. PATCH is used for partial updates, PUT for full replacement.

Answer

POST

Answer

DELETE

Answer

PUT

Question 20

A Python script uses the Cisco Webex API to list all rooms. The response includes pagination via the 'Link' header with 'rel="next"'. What is the correct way to retrieve the next page of rooms?

Accepted Answer

Parse the 'Link' header for the URL with 'rel="next"' and send a GET request to that URL.. The Webex API uses HTTP Link headers for pagination, as specified in RFC 5988. The 'Link' header contains a URL with 'rel="next"' that points directly to the next page of results. To retrieve the next page, you must parse this header, extract the URL, and send a GET request to that URL. This is the standard approach for cursor-based or token-based pagination, which is common in RESTful APIs that avoid offset-based pagination for consistency.

Answer

Increment a page counter and append '?page=2' to the original URL.

Answer

Use the total count returned in the response to calculate the offset.

Answer

Send a POST request to the same endpoint with the 'cursor' parameter.