Content Delivery Network

Concepts

Geographically distributed network of proxy servers and their data centers.

Functionalities

Serve content from locations closer to the user.

Pros

High availability.
Better performance.

Cons

CDN costs could be significant.
Content might be stale.
CDNs require changing URLs for static content to point to the CDN.

Types

Push
- You upload new content from your server to CDN when the content is new or changed.
Pull
- CDN grabs new content from your server to itself when the first user requests the content.