Introduction CDN bandwidth costs can spike unexpectedly due to traffic surges, misconfigured caching, or abuse. Without proper monitoring and controls, these spikes result in significant billing surprises.

Symptoms - CDN bill 2-10x higher than usual - Bandwidth usage graph showing sudden spike - Specific files or endpoints consuming disproportionate bandwidth - Traffic from unexpected geographic regions - Bot traffic inflating bandwidth usage

Common Causes - Large file download going viral - Caching disabled for popular content - Hotlinking from external websites - Bot or scraper traffic - DDoS attack consuming bandwidth

Step-by-Step Fix 1. **Analyze bandwidth usage': ```bash # CloudFront aws cloudfront get-distribution --id E123 # Check CloudWatch for BytesDownloaded metric ```

  1. 1.**Implement bandwidth controls':
  2. 2.- Set up cost alerts
  3. 3.- Enable CDN cost anomaly detection
  4. 4.- Implement request rate limiting
  5. 5.- Block known bot User-Agents
  6. 6.**Optimize caching for popular content':
  7. 7.Increase TTL for static assets and enable compression.

Prevention - Set up CDN cost alerts at 50%, 80%, 100% of budget - Monitor bandwidth usage daily - Implement request rate limiting - Use CDN usage reports for trend analysis - Set up automatic scaling limits where available