Content Distribution & Caching Flashcards

Which cache eviction policy removes the item that has not been accessed for the longest period of time?

Answer: Least Recently Used (LRU)

LRU evicts the item whose last access time is the oldest, making it ideal for workloads with temporal locality.

A CDN edge node receives a request for a resource with 'Cache-Control: no-store'. What must the CDN do?

Answer: Not store any part of the request or response

'no-store' is the strictest directive, instructing the CDN to never persist any part of the transaction.

What is 'cache warming' in the context of CDN operations?

Answer: Pre-populating edge caches with content before user requests arrive

Cache warming proactively pushes content to edge nodes to avoid cold-start latency spikes when traffic begins.

Which HTTP header does a CDN use to indicate that a cached response is stale but still being served while a background revalidation occurs?

Answer: Warning: 110

HTTP Warning code 110 ('Response is Stale') signals that the CDN is serving a stale cached response.

A media company serves video segments of varying popularity. Which caching strategy best handles a long-tail content distribution?

Answer: Use tiered caching with a large regional cache behind edge nodes

Tiered caching allows long-tail content to be fetched once to a regional parent cache and then served to multiple edge nodes.

What does the 's-maxage' directive in a Cache-Control header specifically control?

Answer: Maximum age for shared caches such as CDN edge nodes

's-maxage' overrides 'max-age' specifically for shared/proxy caches, allowing different TTLs for CDN vs. browser.

When a CDN edge node returns an HTTP 304 Not Modified response to a browser, what has occurred?

Answer: The CDN confirmed the browser's cached copy is still valid

A 304 tells the browser its cached version matches the current version, so no body is transmitted, saving bandwidth.