Overview

• CDN is a distributed network of servers that can efficiently deliver web content to users.
• CDNs store cached content on edge servers in point-of-presence (POP) locations that are close to end users, to minimize latency.
• Azure CDN offers developers a global solution for rapidly delivering high-bandwidth content to users by caching their content at strategically placed physical nodes across the world.
• Azure CDN can also accelerate dynamic content, which cannot be cached, by leveraging various network optimizations using CDN POPs.
  • For example, route optimization to bypass Border Gateway Protocol (BGP).

Workflow

1. A user requests a file (asset) by using a URL (<endpoint>.azureedge.net).
   • This name can be an endpoint host name or a custom domain.
2. If no edge servers in the POP have the file in their cache, the POP requests the file from the origin server.
   • The origin server can be an Azure Web App, Azure Cloud Service, Azure Storage, or any public web server.
3. The origin server returns the file to an edge server in the POP.
4. An edge server in the POP caches the file and returns the file to the original requestor.
   • The file is cached on the edge server in the POP until the time-to-live (TTL) specified by its HTTP headers expires.
5. Additional users can then request the same file using the same URL and can also be directed to the same POP.
6. If the TTL for the file hasn't expired, the POP edge server returns the file directly from the cache.

Azure CDN Features

• Dynamic Sites
• Caching Rules
• **HTTPS Custom Domains**
• File Compression
• Geo-Filtering
• Diagnostics Logs