Interview Question Solved
The Answer is CDN
Why does a user in Australia experience 600ms latency while a user in India sees 80ms? It's physics. The solution is a Content Delivery Network.
play_circle Launch Simulator
Why does a user in Australia experience 600ms latency while a user in India sees 80ms? It's physics. The solution is a Content Delivery Network.
play_circle Launch SimulatorSimulates a user visiting for the second time. Content is served from the edge.
The Speed of Light: Even light takes time to travel. The distance between Sydney and Delhi is approximately 10,400 km. In fiber optic cables, light travels slower than in a vacuum (~200,000 km/s).
Network Hops: The internet isn't a direct wire. Your data jumps through dozens of routers, switches, and sub-sea cables. Each "hop" adds processing delay.
Round Trip Time (RTT): To load a page, you send a request (1 trip) and get a response (2 trips).
10,000km x 2 + processing ≈ 600ms.
The CDN stores copies of "static" files (images, CSS, JS) on servers all over the world.
Points of Presence (PoPs) are data centers located near users. Sydney has its own PoP.
If the content is in the Sydney PoP (Cache Hit), the request travels 10km instead of 10,000km.
| Metric | Without CDN | With CDN |
|---|---|---|
| Latency (RTT) | ~600ms | ~80ms |
| Hop Count | 20+ Hops | 2-5 Hops |
| Reliability | Vulnerable to sea cable cuts | Highly Redundant |