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Question 121
A developer is building a REST API using the Cisco DNA Center platform. The API needs to authenticate requests using OAuth 2.0. Which grant type should be used for server-to-server communication without user interaction?
A) Authorization Code grant
B) Implicit grant
C) Client Credentials grant
D) Resource Owner Password Credentials grant
Answer: C
Explanation:
The correct answer is C) Client Credentials grant. The Client Credentials grant is specifically designed for server-to-server communication where the client directly authenticates using its own credentials without requiring user involvement. In this flow, the client sends its client ID and client secret to the authorization server, which returns an access token. This grant type is ideal for applications accessing protected resources on behalf of themselves rather than on behalf of a user. It’s commonly used in microservices, background jobs, and automated processes interacting with Cisco DNA Center APIs.
Option A) is incorrect because Authorization Code grant requires user interaction and is designed for user authentication in web applications. Option B) is incorrect because Implicit grant is outdated and unsuitable for server-to-server communication. Option D) is incorrect because Resource Owner Password Credentials grant requires user credentials and isn’t appropriate for server-to-server scenarios. The Client Credentials grant provides a secure, efficient method for applications to authenticate directly with the Cisco DNA Center platform without user involvement, making it the industry standard for API-to-API communication.
Question 122
A developer is working with Cisco Meraki APIs to manage network devices. The API returns a large dataset with pagination. How should the developer handle pagination efficiently?
A) Fetch all data in a single request regardless of size
B) Implement cursor-based pagination using next page tokens from API responses
C) Manually calculate offsets and limits for each request
D) Fetch data in random page numbers
Answer: B
Explanation:
The correct answer is B) Implement cursor-based pagination using next page tokens from API responses. Cursor-based pagination is the most efficient method for handling large datasets. The API returns a token or URL pointing to the next page of results, allowing the client to fetch data sequentially without calculating offsets. This approach prevents issues like skipped records that can occur with offset-based pagination when data changes between requests. Meraki APIs provide pagination tokens that developers should use to traverse results accurately and efficiently.
Option A) is incorrect because fetching all data simultaneously causes memory issues and poor performance with large datasets. Option C) is incorrect because manual offset calculations are error-prone and inefficient compared to cursor-based methods. Option D) is incorrect because random page fetching produces incomplete and inconsistent results. Cursor-based pagination is the recommended approach in modern REST APIs and ensures reliable, efficient data retrieval from the Cisco Meraki platform.
Question 123
A developer is integrating with Cisco Webex Teams API to send messages to a space. The developer needs to handle rate limiting imposed by the API. What is the best approach?
A) Ignore rate limits and retry immediately upon failure
B) Implement exponential backoff and monitor rate limit headers in responses
C) Send all requests simultaneously to maximize throughput
D) Use a fixed delay between every request
Answer: B
Explanation:
The correct answer is B) Implement exponential backoff and monitor rate limit headers in responses. Rate limiting protects APIs from abuse and ensures fair resource distribution. Exponential backoff involves retrying failed requests with progressively longer delays (e.g., 1 second, 2 seconds, 4 seconds), reducing server load during congestion. Cisco Webex Teams API includes rate limit headers indicating remaining requests and reset times. Monitoring these headers allows applications to proactively adjust request rates before hitting limits, improving reliability and efficiency.
Option A) is incorrect because immediate retries violate rate limits and worsen congestion. Option C) is incorrect because simultaneous requests overwhelm the API and guarantee rate limit violations. Option D) is incorrect because fixed delays are inefficient and don’t adapt to actual rate limit conditions. Exponential backoff combined with header monitoring is the industry standard for handling rate limits in production applications, ensuring robust and respectful API integration.
Question 124
A developer is building an application that uses Cisco ACI (Application Centric Infrastructure) APIs. The application needs to monitor network policies in real-time. Which Cisco ACI feature should be used?
A) Polling the API every 5 seconds
B) WebSocket connections for real-time updates
C) Subscribe to event notifications using Cisco ACI subscriptions
D) Schedule batch queries every hour
Answer: C
Explanation:
The correct answer is C) Subscribe to event notifications using Cisco ACI subscriptions. Cisco ACI supports event-driven subscriptions where applications receive immediate notifications when network policies change, eliminating the need for constant polling. Subscriptions are more efficient than polling, consuming fewer resources and providing real-time visibility. Developers can subscribe to specific managed objects like policies, interfaces, or endpoints, receiving only relevant updates. This approach scales better and reduces latency compared to traditional polling mechanisms.
Option A) is incorrect because frequent polling consumes excessive bandwidth and API quota. Option B) is incorrect because Cisco ACI doesn’t primarily use WebSockets for notifications. Option D) is incorrect because hourly batch queries miss important real-time changes in network policies. Event subscriptions are the recommended Cisco ACI feature for real-time monitoring, enabling efficient, responsive applications that react immediately to network changes.
Question 125
A developer is implementing error handling for a Cisco DNA Center API integration. The API returns a 429 status code. What does this indicate and how should the application respond?
A) The request is malformed; retry immediately with corrected syntax
B) Authentication failed; re-authenticate and retry the request
C) Rate limit exceeded; implement backoff and retry after the specified delay
D) The resource was not found; skip this request
Answer: C
Explanation:
The correct answer is C) Rate limit exceeded; implement backoff and retry after the specified delay. HTTP 429 (Too Many Requests) indicates the client has exceeded the API’s rate limit. The server typically includes a Retry-After header specifying how long to wait before retrying. Applications should implement exponential backoff, respect the Retry-After header, and queue subsequent requests appropriately. Attempting immediate retries violates the rate limit further and may result in temporary blocking.
Option A) is incorrect because 429 doesn’t indicate malformed requests; the issue is rate limiting, not syntax. Option B) is incorrect because 429 doesn’t indicate authentication failure; that would be 401 or 403. Option D) is incorrect because 429 is temporary and requests should be retried, unlike 404 which indicates permanent resource absence. Proper 429 handling demonstrates understanding of HTTP semantics and is essential for building reliable integrations with rate-limited APIs.
Question 126
A developer needs to create a webhook integration with Cisco Webex Events API to receive real-time notifications. What is the most critical security consideration?
A) Webhooks should accept requests from any IP address
B) Validate webhook signatures and use HTTPS endpoints
C) Store webhook secrets in plain text for easy access
D) Disable SSL certificate verification for faster processing
Answer: B
Explanation:
The correct answer is B) Validate webhook signatures and use HTTPS endpoints. Webhook security is paramount because the application receives sensitive data from external sources. Cisco APIs include signature validation mechanisms where each webhook includes a signature header that should be verified using the shared secret. This ensures the webhook actually originated from Cisco and wasn’t forged. HTTPS encryption protects data in transit. Together, these measures prevent unauthorized access, man-in-the-middle attacks, and webhook spoofing.
Option A) is incorrect because accepting requests from any IP creates security vulnerabilities. Option C) is incorrect because storing secrets in plain text exposes them to compromise. Option D) is incorrect because disabling SSL verification removes crucial security protections. Signature validation and HTTPS are fundamental security practices that protect applications from malicious actors attempting to inject false data through webhook manipulation.
Question 127
A developer is using the Cisco Meraki Dashboard API to retrieve network device information. The API response is in JSON format. How should the developer parse this response efficiently?
A) Manually parse JSON strings character by character
B) Use built-in JSON parsing libraries provided by the programming language
C) Convert JSON to XML before parsing
D) Store raw JSON strings without parsing
Answer: B
Explanation:
The correct answer is B) Use built-in JSON parsing libraries provided by the programming language. Most modern programming languages include built-in JSON parsing libraries (e.g., json in Python, JSON.parse in JavaScript, gson in Java) that efficiently deserialize JSON into native data structures. These libraries handle edge cases, encoding issues, and validation automatically. Using built-in parsers is faster, more reliable, and requires less code than manual parsing. It also reduces the risk of parsing errors and security vulnerabilities.
Option A) is incorrect because manual character-by-character parsing is inefficient, error-prone, and unnecessary. Option C) is incorrect because converting JSON to XML adds unnecessary complexity and overhead. Option D) is incorrect because storing unparsed JSON strings prevents accessing structured data. Built-in JSON parsing libraries are the standard approach in professional development and should always be used for handling API responses.
Question 128
A developer is building a microservice that calls multiple Cisco platform APIs sequentially. The calls experience high latency. Which approach would improve performance?
A) Serialize all API calls to ensure sequential execution
B) Implement asynchronous/concurrent API calls using threading or async-await
C) Increase the API timeout values significantly
D) Make API calls less frequently
Answer: B
Explanation:
The correct answer is B) Implement asynchronous/concurrent API calls using threading or async-await. When multiple independent API calls are made sequentially, the total latency equals the sum of individual response times. Asynchronous or concurrent execution allows the application to initiate multiple requests simultaneously and wait for all responses in parallel, reducing total latency significantly. Modern languages provide async-await syntax or threading libraries to implement concurrency elegantly. This approach maximizes resource utilization and improves overall application responsiveness.
Option A) is incorrect because serialization intentionally increases latency by executing calls one after another. Option C) is incorrect because increasing timeouts doesn’t reduce actual latency; it just allows longer waits. Option D) is incorrect because reducing call frequency doesn’t solve the underlying performance issue. Concurrent API calls are essential for building responsive applications that efficiently interact with multiple Cisco platform APIs.
Question 129
A developer is working with Cisco DNA Center northbound APIs. The API documentation specifies request and response schemas. How should the developer validate incoming API data?
A) Skip validation to improve response speed
B) Validate data against the documented schema before processing
C) Assume all data is correct without verification
D) Validate only if errors occur during processing
Answer: B
Explanation:
The correct answer is B) Validate data against the documented schema before processing. Schema validation ensures data integrity and catches errors early. By validating incoming data against the documented schema, developers prevent processing invalid or malicious data that could cause application failures or security issues. Many tools and libraries provide automatic schema validation. This defensive programming practice improves reliability, security, and user experience by catching problems before they propagate through the application.
Option A) is incorrect because skipping validation allows corrupt data to cause downstream failures. Option C) is incorrect because trusting unverified data introduces security vulnerabilities and stability issues. Option D) is incorrect because discovering errors during processing is inefficient and may cause partial state corruption. Schema validation is a best practice that ensures robust, secure applications handling Cisco DNA Center API responses.
Question 130
A developer is implementing environment-specific configurations for a Cisco platform integration. The application runs in development, staging, and production environments. How should credentials and endpoints be managed?
A) Hardcode all credentials and endpoints in the source code
B) Use environment variables and configuration files specific to each environment
C) Store credentials in version control systems
D) Use the same credentials for all environments
Answer: B
Explanation:
The correct answer is B) Use environment variables and configuration files specific to each environment. Environment-specific configuration management separates code from deployment-specific values. Environment variables store sensitive credentials securely without embedding them in code, while configuration files manage non-sensitive parameters like API endpoints. This approach enables the same codebase to run across different environments with appropriate credentials and endpoints. Tools like environment variable managers, Docker secrets, and Kubernetes ConfigMaps facilitate this pattern in modern deployments.
Option A) is incorrect because hardcoding exposes credentials to anyone with code access. Option C) is incorrect because version control systems store credentials permanently in history. Option D) is incorrect because using identical credentials across environments creates security risks and potential cross-environment data leaks. Environment-based configuration management is essential for secure, scalable application deployments.
Question 131
A developer is designing an API client library for Cisco Webex APIs. The library should handle network timeouts gracefully. What is the best approach?
A) Let timeouts crash the application immediately
B) Implement configurable timeouts with retry logic and fallback mechanisms
C) Use infinite timeouts to guarantee completion
D) Ignore timeout errors silently
Answer: B
Explanation:
The correct answer is B) Implement configurable timeouts with retry logic and fallback mechanisms. Configurable timeouts allow applications to adapt to different network conditions. When timeouts occur, retry logic with exponential backoff can recover transient failures. Fallback mechanisms provide alternative behavior when requests ultimately fail, improving user experience. This approach balances reliability with responsiveness, ensuring applications handle network issues gracefully without hanging indefinitely or crashing prematurely.
Option A) is incorrect because immediate crashes provide poor user experience. Option C) is incorrect because infinite timeouts cause applications to hang indefinitely. Option D) is incorrect because silently ignoring errors masks problems and causes data inconsistencies. Implementing robust timeout handling with retries and fallbacks demonstrates production-grade thinking and ensures reliable API integrations.
Question 132
A developer is integrating with multiple Cisco APIs that have different authentication mechanisms. One uses API keys, another uses OAuth 2.0. How should authentication be implemented?
A) Create separate client libraries for each authentication type
B) Implement a single unified authentication layer supporting multiple mechanisms
C) Hardcode each authentication method directly in API calls
D) Use only the most common authentication method
Answer: B
Explanation:
The correct answer is B) Implement a single unified authentication layer supporting multiple mechanisms. A unified authentication layer abstracts different authentication mechanisms behind a common interface, simplifying integration and maintenance. This approach follows the adapter pattern, allowing applications to seamlessly work with multiple Cisco APIs without duplicating authentication logic. The layer handles authentication details, token management, and refresh automatically, making the rest of the application unaware of specific authentication mechanisms.
Option A) is incorrect because separate libraries duplicate code and complicate dependency management. Option C) is incorrect because hardcoding spreads authentication logic throughout the codebase. Option D) is incorrect because ignoring supported authentication mechanisms limits flexibility. A unified authentication layer provides clean separation of concerns and maintainability, following SOLID principles.
Question 133
A developer needs to implement logging for API interactions with Cisco platforms. Which information should be logged for debugging while maintaining security?
A) Log all request and response data including credentials
B) Log request URLs, response status codes, and timestamps, but exclude sensitive data like credentials and tokens
C) Avoid logging to prevent performance impact
D) Log only error responses
Answer: B
Explanation:
The correct answer is B) Log request URLs, response status codes, and timestamps, but exclude sensitive data like credentials and tokens. Strategic logging provides debugging information without exposing sensitive data. Logging URLs helps trace execution paths, status codes indicate success or failure, and timestamps identify timing issues. However, credentials, access tokens, and personal information must never be logged as they could be exposed if logs are compromised. This balanced approach enables effective debugging while maintaining security and compliance requirements.
Option A) is incorrect because logging credentials creates severe security vulnerabilities. Option C) is incorrect because modern logging with efficient appenders has minimal performance impact. Option D) is incorrect because logging only errors misses important debugging information. Strategic logging is essential for production applications and must balance debugging needs with security concerns.
Question 134
A developer is building a Cisco DNA Center integration that processes network device events. Events arrive through webhooks asynchronously. How should the application handle event processing to ensure reliability?
A) Process events synchronously and block on each event
B) Use message queues to buffer events and process them asynchronously with acknowledgment
C) Discard events if processing is busy
D) Retry failed events indefinitely without limits
Answer: B
Explanation:
The correct answer is B) Use message queues to buffer events and process them asynchronously with acknowledgment. Message queues decouple event receipt from processing, allowing applications to acknowledge receipt immediately while processing events asynchronously. This prevents webhook timeouts and ensures no events are lost. Failed messages can be retried with backoff strategies, and dead-letter queues capture permanently failed messages for investigation. This architecture provides resilience, scalability, and reliability for event-driven systems.
Option A) is incorrect because synchronous processing causes timeouts and event loss during high load. Option C) is incorrect because discarding events loses data. Option D) is incorrect because infinite retries without limits cause resource exhaustion. Message-queue-based event processing is the standard approach for reliable, scalable event handling in distributed systems.
Question 135
A developer is implementing caching for frequently accessed Cisco Meraki API responses. What is the appropriate caching strategy?
A) Cache all API responses indefinitely
B) Implement cache with TTL (Time-To-Live) and cache invalidation mechanisms
C) Never cache API responses
D) Cache only failed responses
Answer: B
Explanation:
The correct answer is B) Implement cache with TTL and cache invalidation mechanisms. Caching reduces latency and API quota consumption, but stale data causes inconsistencies. TTL ensures cached data expires after a specified duration, automatically refreshing from the API. Cache invalidation mechanisms explicitly remove cache entries when data changes, maintaining consistency. Different data types warrant different TTLs; device lists might cache for hours while real-time metrics cache for seconds. This balanced approach optimizes performance while maintaining data freshness.
Option A) is incorrect because indefinite caching serves stale data and prevents visibility into changes. Option C) is incorrect because reasonable caching improves performance significantly. Option D) is incorrect because caching failures prevents recovery as conditions improve. TTL-based caching with invalidation is the industry standard for efficient, consistent data management.
Question 136
A developer is designing an API client that needs to handle HTTP redirects (3xx status codes). How should redirects be handled?
A) Treat all redirects as errors and fail the request
B) Automatically follow redirects up to a reasonable limit, preventing infinite redirect loops
C) Manually construct new requests for every redirect
D) Ignore redirects and continue with original requests
Answer: B
Explanation:
The correct answer is B) Automatically follow redirects up to a reasonable limit, preventing infinite redirect loops. HTTP clients should transparently follow redirects (typically up to 5-10) to simplify integrations. However, they must detect redirect loops to prevent infinite recursion. Most HTTP libraries handle this automatically, following 3xx responses according to HTTP specifications. Limiting redirect depth prevents attackers from creating malicious redirect chains that consume resources.
Option A) is incorrect because treating redirects as errors prevents legitimate requests when endpoints move. Option C) is incorrect because manual redirect handling is error-prone and unnecessary. Option D) is incorrect because ignoring redirects causes requests to fail. Automatic redirect following with loop detection is the standard HTTP client behavior that simplifies integration with dynamic endpoints.
Question 137
A developer is building a dashboard application that displays real-time data from Cisco Webex APIs. The application currently refreshes data every 30 seconds. How can efficiency be improved?
A) Increase refresh frequency to every 5 seconds for fresher data
B) Implement change detection or WebSocket connections to receive updates only when data changes
C) Stop refreshing to reduce API calls
D) Refresh less frequently, every 5 minutes
Answer: B
Explanation:
The correct answer is B) Implement change detection or WebSocket connections to receive updates only when data changes. Event-driven updates are more efficient than polling at fixed intervals. WebSocket connections or server-sent events allow the Cisco Webex API to push updates to the client whenever data changes, eliminating unnecessary API calls and reducing latency. Change detection mechanisms compare new and old data, updating only UI elements affected by changes. This approach consumes fewer resources, reduces API quota usage, and provides better user experience with fresher, more responsive data.
Option A) is incorrect because more frequent polling increases API quota consumption and server load. Option C) is incorrect because stopping updates entirely eliminates real-time capabilities. Option D) is incorrect because less frequent polling delays data visibility. Event-driven update mechanisms significantly improve efficiency and responsiveness compared to fixed-interval polling.
Question 138
A developer is implementing unit tests for code that calls Cisco platform APIs. How should external API dependencies be handled in tests?
A) Make actual API calls to external services during unit testing
B) Use mocks or stubs to simulate API responses without calling external services
C) Skip testing API integration code entirely
D) Use live credentials in test environments
Answer: B
Explanation:
The correct answer is B) Use mocks or stubs to simulate API responses without calling external services. Mocking isolates code under test from external dependencies, enabling fast, reliable, repeatable tests. Mocks simulate API responses, allowing developers to test various scenarios including error conditions without external service availability. This approach follows best practices for unit testing, ensuring tests remain deterministic and don’t depend on external service state or network conditions. Mocking frameworks like unittest.mock in Python or Jest in JavaScript facilitate this pattern.
Option A) is incorrect because actual API calls make tests slow, flaky, and dependent on external services. Option C) is incorrect because integration with external services requires testing. Option D) is incorrect because using live credentials in tests poses security risks. Mocking external dependencies is fundamental to writing effective, maintainable unit tests.
Question 139
A developer is documenting a REST API for other developers to consume. What is essential to include in API documentation?
A) Only list available endpoints without details
B) Include endpoint descriptions, request/response formats, authentication requirements, error codes, and usage examples
C) Assume developers know how to use all APIs
D) Document only successful scenarios
Answer: B
Explanation:
The correct answer is B) Include endpoint descriptions, request/response formats, authentication requirements, error codes, and usage examples. Comprehensive API documentation enables developers to integrate effectively. Endpoint descriptions explain functionality, request/response formats show data structures, authentication requirements clarify security mechanisms, error codes help developers handle failures, and usage examples accelerate implementation. Tools like Swagger/OpenAPI automate documentation generation and provide interactive testing interfaces. Well-documented APIs reduce integration time and support requests significantly.
Option A) is incorrect because minimal documentation forces developers to guess functionality and parameters. Option C) is incorrect because different developers have different experience levels. Option D) is incorrect because understanding error scenarios is crucial for robust implementations. Comprehensive documentation following OpenAPI standards is essential for professional, usable APIs.
Question 140
A developer is migrating an application from a deprecated Cisco API version to a newer version. How should this migration be managed to avoid service disruption?
A) Immediately switch all requests to the new API version
B) Run both API versions in parallel, gradually migrating traffic while monitoring for differences
C) Keep using the deprecated version indefinitely
D) Switch at a random time without planning
Answer: B
Explanation:
The correct answer is B) Run both API versions in parallel, gradually migrating traffic while monitoring for differences. Parallel operation allows teams to validate the new API’s behavior before complete migration. Gradually increasing traffic to the new version identifies compatibility issues early, enabling fixes before complete cutover. Monitoring detects differences in responses that might affect downstream systems. This approach minimizes service disruption and rollback risk. Feature flags can control which API version is used, enabling quick rollbacks if issues arise.
Option A) is incorrect because immediate switching risks widespread failures if undiscovered incompatibilities exist. Option C) is incorrect because deprecated versions eventually become unavailable. Option D) is incorrect because unplanned migrations guarantee disruption and failures. Gradual parallel migration is the standard approach for managing version transitions in production systems with minimal risk.
