Design a Content Delivery Network (CDN)

Functional Requirements:

• Efficiently deliver static content (e.g., images, videos, CSS/JS files) to users across different geographic locations.
• Cache content at edge servers to reduce latency and offload origin servers.
• Route user requests to the nearest or best-performing edge server.
• Support cache invalidation or content update when the origin content changes.
• Provide basic monitoring and logging for traffic and cache statistics.

Non-Functional Requirements:

• Low latency and high throughput for content delivery.
• High availability and reliability, minimizing downtime.
• Scalability to handle increasing traffic and content volume.
• Security: protect against common attacks (e.g., DDoS), support HTTPS.
• Cost-effective operation, optimizing for bandwidth and infrastructure usage.