CDN

CDN (Content Delivery Network) is a distributed server network that optimizes web content delivery.

What is CDN?

CDN is a geographically distributed server network that stores and delivers web content from locations close to users.

Main Features

Distribution

  • Distributed servers: Servers in multiple locations
  • Cache: Content caching
  • Proximity: Delivery from nearby locations
  • Redundancy: Server redundancy

Optimization

  • Compression: Content compression
  • Minification: Code minification
  • Image optimization: Image optimization
  • HTTP/2: HTTP/2 support

Security

  • DDoS Protection: DDoS protection
  • SSL/TLS: SSL/TLS certificates
  • WAF: Web Application Firewall
  • Bot Protection: Bot protection

Benefits

Performance

  • Reduced latency: Lower latency
  • Speed: Faster load times
  • Availability: Higher availability
  • Scalability: Automatic scalability

Costs

  • Bandwidth reduction: Lower bandwidth usage
  • Server reduction: Lower server requirements
  • Efficiency: Higher efficiency
  • ROI: Better return on investment

User Experience

  • Fast loading: Pages that load faster
  • Availability: Higher availability
  • Consistency: Consistent experience
  • Mobile: Mobile optimization

CDN Types

By Purpose

  • Web: CDN for websites
  • Video: CDN for video
  • Applications: CDN for applications
  • API: CDN for APIs

By Model

  • Public: Public CDN
  • Private: Private CDN
  • Hybrid: Hybrid CDN
  • Edge: Edge CDN

Providers

Enterprise

  • Cloudflare: Cloudflare CDN
  • AWS CloudFront: Amazon CloudFront
  • Azure CDN: Microsoft Azure CDN
  • Google Cloud CDN: Google Cloud CDN

Specialized

  • Akamai: Akamai CDN
  • Fastly: Fastly CDN
  • MaxCDN: MaxCDN
  • KeyCDN: KeyCDN

Open Source

  • Varnish: Varnish Cache
  • Nginx: Nginx
  • Apache: Apache HTTP Server
  • Squid: Squid Proxy

Implementation

Phase 1: Analysis

  • Content: Analyze content
  • Audience: Analyze audience
  • Performance: Evaluate current performance
  • Requirements: Define requirements

Phase 2: Selection

  • Providers: Evaluate providers
  • Features: Compare features
  • Costs: Evaluate costs
  • Support: Evaluate support

Phase 3: Configuration

  • Configuration: Configure CDN
  • DNS: Configure DNS
  • SSL: Configure SSL
  • Cache: Configure cache

Phase 4: Optimization

  • Monitoring: Monitor performance
  • Adjustments: Adjust configuration
  • Optimization: Optimize content
  • Improvement: Continuous improvement

Configuration

DNS

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; DNS configuration for CDN
www.example.com.    CNAME   cdn.example.com.
cdn.example.com.     CNAME   d1234567890.cloudfront.net.

Headers

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# Cache headers
Cache-Control: public, max-age=31536000
Expires: Thu, 31 Dec 2025 23:59:59 GMT
ETag: "abc123"
Last-Modified: Wed, 21 Oct 2024 07:28:00 GMT

SSL

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# SSL configuration for CDN
server {
    listen 443 ssl;
    server_name example.com;
    
    ssl_certificate /path/to/certificate.crt;
    ssl_certificate_key /path/to/private.key;
    
    location / {
        proxy_pass http://backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

Best Practices

Configuration

  • Cache: Configure cache appropriately
  • Headers: Configure headers correctly
  • SSL: Implement SSL
  • Monitoring: Configure monitoring

Optimization

  • Content: Optimize content
  • Images: Optimize images
  • Code: Minify code
  • Compression: Enable compression

Monitoring

  • Performance: Monitor performance
  • Availability: Monitor availability
  • Errors: Monitor errors
  • Metrics: Analyze metrics

References