Introduction to a CDN

A CDN combines distributed delivery locations with routing and cache policy. Define which requests it can serve locally, when it must contact the origin, and how it handles changes before evaluating its latency and availability benefits.

A content delivery network (CDN) is a distributed system of servers strategically placed across various geographic locations to improve the speed and reliability of online content delivery. Instead of relying on a single origin server, a CDN uses a network of proxy servers positioned closer to the end users.

These proxy servers operate at the network edge and are often referred to as edge servers. By caching content near users, edge servers reduce latency, conserve bandwidth, and protect the origin server from traffic spikes.

Serving a reusable response from an edge location can shorten the delivery path and reduce origin work. Dynamic or personalized responses need explicit cache rules and may still require origin processing. Edge proximity does not guarantee sufficient bandwidth on every link to the user.

Note: A cache and a CDN serve different purposes. A cache stores frequently accessed data closer to the application or user to reduce latency and backend load. A CDN distributes content across geographically dispersed edge servers to reduce network latency for end users.