CDN Architecture & Components 4

Question 1

What is the purpose of 'Edge Side Includes' (ESI) in CDN architecture?

Accepted Answer

To assemble page fragments with different cache TTLs at the edge before delivery

Answer

ESI allows the CDN to cache page components independently and stitch them together at the edge, so personalized and cached sections coexist.

Question 2

Which TCP optimization technique do CDN edges commonly use to improve throughput for users with high-latency connections?

Accepted Answer

TCP Fast Open and larger initial congestion windows

Answer

TCP Fast Open and increased initial congestion windows reduce the number of round trips needed before the connection reaches full throughput.

Question 3

In a CDN context, what is 'edge compute' or 'serverless at the edge' primarily used for?

Accepted Answer

Executing lightweight request/response logic (e.g., A/B testing, auth, personalization) at PoPs

Answer

Edge compute platforms (e.g., Cloudflare Workers, Fastly Compute) run small scripts at PoPs to customize responses without a round trip to the origin.

Question 4

What does 'Cache-Control: s-maxage' specifically control in a CDN environment?

Accepted Answer

How long shared (proxy/CDN) caches may store a response, independently of browser cache TTL

Answer

s-maxage overrides max-age for shared caches like CDNs, letting operators set different CDN and browser TTLs in the same header.

Question 5

Which CDN feature allows operators to instantly remove a cached object from all edge nodes worldwide?

Accepted Answer

Surrogate-key / cache tag purging

Answer

Surrogate keys (or cache tags) group related objects so a single API call purges all tagged content across the entire CDN fleet instantly.

(CDN) Content Delivery Network Certification Practice Test

(CDN) Content Delivery Network Certification Practice Test

CDN Architecture & Components 4