Content Delivery Networks (CDN)

A CDN is a global network of "Edge" servers. Its job is to move content as close to the user as possible. Think of it like a local convenience store: instead of driving across the country to a central warehouse for milk, you grab it from the corner store (The Edge). The catch? This works perfectly for non-changing goods (static images, CSS, JavaScript files). If you need something custom-made just for you (like viewing your bank statement), the store still has to call the central warehouse (The Origin) to fetch the real data.

Comparison: Hosting vs. CDN

Feature	Standard Web Hosting	CDN (Content Delivery Network)
Main Purpose	To store your files and database.	To distribute files globally.
IP Address	The "Real" IP of your server.	A "Proxy" IP near the user.
Performance	Varies by user location.	Consistent, low-latency worldwide.
Traffic Handling	Can crash if too many visit at once.	Absorbs massive traffic spikes.

The Lifecycle of a Request

1. User Request: A user in London wants to see viewip.org.
2. DNS Routing: Through Anycast, the request is sent to the nearest CDN Edge node in London.
3. Cache Check:
   • HIT: The Edge node already has the image/file. It serves it in 10ms.
   • MISS: The Edge node doesn't have it. It fetches it from the US Origin, serves the user, and saves a copy for the next person.