juniorCDN
Explain the 'Origin Server'.
Updated Apr 28, 2026
Short answer
The origin server is the source of truth where the original versions of web files are stored.
Deep explanation
CDN architecture involves a network of proxy servers. When a user requests content, the DNS routes them to the nearest Edge server. This minimizes the physical distance data travels (the 'last mile'), reducing round-trip time (RTT). Key protocols like TCP and TLS are terminated at the edge, further speeding up the handshake process.
Real-world example
A user in Tokyo accessing a website hosted in New York. Without a CDN, the request travels across the ocean. With a CDN, the user gets the image from a Tokyo-based edge server.
Common mistakes
- Thinking a CDN replaces a web host
- it actually acts as a performance layer on top of it.
Follow-up questions
- How does DNS-based routing work in CDNs?
- Can static and dynamic content both be served via CDN?