CDN (Content Delivery Network)
Difficulty: Easy | Topic #5
What to Learn
How CDNs cache and serve static assets from edge nodes, cache-control headers, origin shield, dynamic vs static content, CDN invalidation strategies.
Resources
- Hello Interview: Networking Essentials ↗
- ByteByteGo: What Is A CDN? How Does It Work? ↗
- InterviewPen: How a CDN Works ↗
Covered by Problems
| Problem | Difficulty | Link |
|---|---|---|
| File Storage/Dropbox | Easy | → |
| Photo Sharing (Instagram) | Medium | → |
| Video Streaming (YouTube) | Medium | → |
Key Concepts to Master
- Edge PoP topology and how content reaches the edge
- Cache-control and Surrogate-Control headers
- Origin shield to protect origin from cache misses
- Push vs pull CDN models
- CDN invalidation (path-based, tag-based) and its cost