CDN Network - Architecture
Global Architecture
┌─────────────────────────────────────────────────────────┐
│ Users (Global) │
└────────────────────┬────────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ GeoDNS / Anycast Routing │
│ - Route to nearest edge location │
│ - Health-based routing │
│ - Load balancing │
└────────────────────┬────────────────────────────────────┘
│
┌────────────┼────────────┬────────────┐
▼ ▼ ▼ ▼
┌──────────┐ ┌──────────┐ ┌──────────┐ ┌──────────┐
│ Edge │ │ Edge │ │ Edge │ │ Edge │
│ US-East │ │ EU-West │ │ Asia- │ │ Other │
│ │ │ │ │ Pacific │ │ Regions │
│ Cache │ │ Cache │ │ Cache │ │ Cache │
│ + WAF │ │ + WAF │ │ + WAF │ │ + WAF │
└────┬─────┘ └────┬─────┘ └────┬─────┘ └────┬─────┘
│ │ │ │
└─────────────┴─────────────┴─────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ Origin Shield (Optional) │
│ - Collapse requests to origin │
│ - Additional caching layer │
└────────────────────┬────────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────────┐
│ Origin Servers │
│ - Web servers, application servers, storage │
└─────────────────────────────────────────────────────────┘Edge Location Components
- Load Balancer: Distribute traffic across edge servers
- Cache Servers: Store and serve cached content
- WAF: Web Application Firewall for security
- DDoS Protection: Mitigate attacks at edge
- SSL/TLS Termination: Handle HTTPS at edge
- Edge Computing: Run serverless functions
Request Flow
- User requests content
- GeoDNS routes to nearest edge
- Edge checks cache (hit → serve, miss → fetch from origin)
- Edge caches response
- Edge serves content to user
Caching Hierarchy
- L1 (Edge): Memory cache, <1ms latency
- L2 (Regional): SSD cache, <10ms latency
- L3 (Origin Shield): Protect origin, <50ms latency
- Origin: Source of truth, <100ms latency
Intelligent Routing
- GeoDNS: Route based on user location
- Anycast: Single IP, multiple locations
- Health Checks: Route around failures
- Performance-Based: Route to fastest edge
- Cost-Based: Optimize for cost
This architecture provides global content delivery with low latency and high availability.