Why it matters

Every fast website uses a CDN. Understanding architecture enables debugging cache issues and picking the right CDN features.

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The architecture

PoPs: datacenters distributed globally. Each has HTTP servers + caches.

Routing: user routed to nearest PoP via Anycast (same IP announced from multiple locations) or GeoDNS.

CDN architectureOriginsource of truthPoPs globalcache + serveAnycast / GeoDNSroute to nearestCache hit ratio + edge compute + DDoS protection are key CDN value-adds
CDN structure.
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How it works end to end

Cache hit ratio: fraction of requests served from cache. Higher = better cost + latency.

Cache invalidation: URL purge or tag-based invalidation.

Edge compute: run code at PoP (Cloudflare Workers, Fastly Compute@Edge). Sub-millisecond response.

DDoS protection: distribute attack traffic across many PoPs.