CDN API Gateway & Rate Limiting 4

Question 1

An API gateway must handle 10,000 requests per second but the origin can only process 1,000 RPS. Which pattern should the gateway use to buffer the excess traffic?

Accepted Answer

Request queuing with backpressure

Answer

Request queuing with backpressure buffers excess requests and signals upstream clients to slow down, protecting the origin from overload.

Question 2

Which OAuth 2.0 grant type is most appropriate for server-to-server CDN API authentication without a human user?

Accepted Answer

Client Credentials

Answer

The Client Credentials grant allows a service to authenticate directly with the authorization server using its own credentials, with no user interaction required.

Question 3

A sliding window rate limiter differs from a fixed window rate limiter in that it:

Accepted Answer

Prevents burst exploitation at window boundaries

Answer

A sliding window calculates the request count over the last N seconds continuously, preventing clients from exploiting the reset moment of fixed windows.

Question 4

What is 'API versioning' and why is it important in a CDN API gateway deployment?

Accepted Answer

Allowing backward-compatible evolution of the API without breaking existing clients

Answer

API versioning lets providers evolve the API contract while existing clients continue to use older versions without disruption.

Question 5

A CDN provider needs to expose a single API endpoint that aggregates data from five internal microservices. Which API gateway pattern accomplishes this?

Accepted Answer

API composition / aggregation

Answer

API composition aggregates responses from multiple backend microservices into a single client-facing response, reducing client round trips.

(CDN) Content Delivery Network Certification Practice Test

(CDN) Content Delivery Network Certification Practice Test

CDN API Gateway & Rate Limiting 4