CDN

Problem

Your website is hosted in Vienna. A user in Sydney downloads a 20 MB image. Every request crossing half the planet increases latency and repeatedly consumes origin capacity.

Solution — Content Delivery Network

Cache content at geographically distributed edge locations.

Vienna origin
      ↓
CDN edges
  ↙   ↓   ↘
US   EU   Australia

Users retrieve suitable content from a nearby edge when cached there.

Core idea: a CDN moves cacheable content closer to users.