CDN (Content Delivery Network)

A geographically distributed network of servers that delivers web content to users from the nearest location, improving speed and reliability.

What is a CDN?

A Content Delivery Network (CDN) is a distributed network of servers that delivers web content to users based on their geographic location. By caching content at edge locations worldwide, CDNs reduce latency and improve the user experience.

How CDNs Work

When a user requests content:

DNS directs the request to the nearest CDN edge server
If cached, the edge server delivers the content directly
If not cached, the edge retrieves it from the origin server
Content is cached at the edge for future requests

What CDNs Cache

Static assets (images, CSS, JavaScript)
Video and streaming content
Software downloads
API responses
Dynamic content (with proper configuration)

Benefits

Faster Load Times: Content served from nearby servers
Reduced Bandwidth Costs: Offloads traffic from origin
High Availability: Distributed infrastructure handles failures
DDoS Protection: Absorbs attack traffic across network
Global Reach: Consistent performance worldwide

Major CDN Providers

Cloudflare, Akamai, Amazon CloudFront, Fastly, Microsoft Azure CDN