#🧱 Building Block: Content Delivery Network (CDN)

#Overview

A CDN is a geographically distributed group of servers that work together to provide fast delivery of Internet content.

#Key Concepts

• Edge Locations: Data centers located close to users to reduce latency.
• Push CDN: Content is pushed to the CDN when updated on the origin.
• Pull CDN: CDN fetches content from the origin on the first request (more common).
• TTL (Time To Live): Defines how long content remains cached at the edge.

#Benefits

• Reduced Latency: Bringing content closer to users (lower RTT).
• Reduced Bandwidth Costs: Offloading traffic from the origin server.
• DDoS Protection: Absorbing large-scale attacks at the edge.

#When to Use

• Static Assets: Images, CSS, JS, videos.
• Global Audience: When users are spread across different geographical regions.

#Trade-offs

• Pros: Significant performance boost, increased reliability.
• Cons: Cache invalidation is hard, potentially stale content, cost.