A CDN's job is to put a copy of your content near every viewer so the request never has to cross the world. The major players in 2026 — Akamai, Cloudflare, Fastly, AWS CloudFront, Google Cloud CDN, Edgio (formerly Limelight + Verizon), CDN77 — each operate hundreds of POPs in dozens of countries. When a viewer requests https://example.com/segment.m4s, DNS routes the request to the nearest POP, which either serves a cached copy or fetches it once from origin and caches it for everyone else.
For streaming the relevant CDN behaviours are: caching of immutable segments (TTL = years for VOD, seconds for live manifests), origin shielding (a regional cache layer in front of true origin), edge logic (signed-URL verification, geo-blocking, header manipulation), and multi-region routing. A well-tuned CDN keeps cache hit ratio above 95 % for VOD and 85 % for live, meaning fewer than 1 in 7 requests reach origin even during peak live events.
CDN cost is the largest operating expense of a streaming service after content licensing. At 2026 enterprise rates, a few cents per GB summed across petabytes per month becomes the line item every CFO scrutinises. This is why multi-CDN setups exist — to play vendors off each other for pricing — and why CDN selection logic (content steering, real-time CDN switching) is a serious engineering investment for any tier-1 OTT.
