QA
Beginner LevelSystem Design & Architecture

What is a Content Delivery Network (CDN) and how does Edge Caching reduce latency?

❓ Interview Prompt: Explain Content Delivery Networks (CDNs), Points of Presence (PoPs), edge caching, origin shield, and cache invalidation strategies.

A Content Delivery Network (CDN) is a geographically distributed network of Point of Presence (PoP) edge servers that cache static assets (images, JS, CSS, video chunks) close to end users:

Benefits & Mechanics:

1
Latency Reduction: Serves assets from an edge node located 10ms away instead of fetching from an origin server 200ms away.
2
Origin Offloading: Reduces bandwidth and CPU load on origin web servers by up to 90%.
3
DDoS Protection: Absorbs volumetric Layer 3/4 network attacks at the edge.

Code Implementation Example

markdown
CDN Edge Routing Workflow:

User in Tokyo ──> [Tokyo CDN Edge PoP] ──(Cache Hit! 5ms)──> Returns Static Asset
                       │
                 (Cache Miss)
                       │
                       ▼
            [Origin Server in US-East]
💡CDN Edge PoP caching static assets near global users.
🎯 Interview Key Takeaway

Deploy CDNs to cache static media and API responses at edge PoPs globally, reducing user latency and shielding origin servers.

#System Design#CDN#Edge Caching#Latency#Beginner
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