Problem Statement

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CDN Network - Problem Statement

Overview

Design a global Content Delivery Network (CDN) similar to CloudFront, Akamai, or Cloudflare that delivers content from edge locations closest to users, reducing latency and improving performance for websites, APIs, and streaming services worldwide.

Functional Requirements

Content Delivery

  • Static Content: Images, CSS, JavaScript, fonts, documents
  • Dynamic Content: API responses, personalized pages
  • Video Streaming: Live and on-demand video delivery
  • Software Distribution: Large file downloads
  • SSL/TLS Termination: HTTPS at edge locations
  • HTTP/2 and HTTP/3: Modern protocol support

Edge Features

  • Caching: Intelligent caching at edge locations
  • Compression: Gzip, Brotli compression
  • Image Optimization: Resize, format conversion, quality adjustment
  • Minification: CSS/JS minification
  • Edge Computing: Run code at edge (serverless functions)
  • Request Routing: Intelligent routing to optimal origin

Geographic Distribution

  • Global POPs: 100+ edge locations worldwide
  • GeoDNS: Route users to nearest edge
  • Anycast: Single IP, multiple locations
  • Regional Caching: Multi-tier caching hierarchy
  • Origin Shield: Protect origin from traffic spikes

Non-Functional Requirements

Performance

  • Latency: <50ms to nearest edge
  • Throughput: 100Gbps+ per edge location
  • Cache Hit Rate: >90% for static content
  • Time to First Byte: <100ms
  • Global Coverage: <100ms latency for 95% of users

Scalability

  • Traffic: Handle 10M+ requests per second globally
  • Bandwidth: 100Tbps+ aggregate bandwidth
  • Storage: Petabytes of cached content
  • Concurrent Users: Billions of users
  • DDoS Protection: Mitigate multi-Tbps attacks

Reliability

  • Availability: 99.99% uptime
  • Failover: Automatic failover to healthy edges
  • Origin Protection: Shield origin from failures
  • Graceful Degradation: Serve stale on origin failure

Success Metrics

  • Latency Reduction: 50-70% improvement
  • Origin Offload: 90%+ traffic served from edge
  • Cache Hit Rate: >90%
  • Availability: 99.99%+
  • Cost Savings: 60% reduction in origin bandwidth costs

This problem statement establishes the foundation for designing a production-grade global CDN network.