The design points of a CDN multi-level cache architecture focus on optimizing content delivery efficiency, reducing latency, and improving scalability. Here are the key aspects:
-
Hierarchical Cache Layers:
- Edge Cache (First Level): Deployed at the closest points to end-users (e.g., POPs), storing frequently accessed content to minimize latency.
- Intermediate Cache (Second Level): Located between edge nodes and origin servers, reducing load on origins by caching less frequently accessed but still reusable content.
- Origin Cache (Third Level): The source of truth, where dynamic or uncached content is generated or retrieved.
-
Cache Invalidation & Freshness:
- Use TTL (Time-To-Live) policies to manage cache expiration.
- Implement purge mechanisms to invalidate stale content when updates occur.
-
Load Balancing & Traffic Distribution:
- Distribute requests intelligently across cache layers to prevent hotspots.
- Use DNS-based or Anycast routing for optimal path selection.
-
Scalability & Redundancy:
- Design for horizontal scaling to handle traffic spikes.
- Ensure redundancy at each layer to avoid single points of failure.
-
Content Preloading & Prefetching:
- Proactively cache popular content during off-peak hours.
- Predictively fetch content based on user behavior patterns.
Example: A video streaming platform uses a multi-level CDN cache:
- Edge caches store the most popular videos.
- Intermediate caches hold less popular but still frequently accessed content.
- The origin server streams new or uncached videos.
For such scenarios, Tencent Cloud CDN provides a robust multi-level caching solution with features like intelligent routing, dynamic content acceleration, and real-time cache purging to ensure high performance and reliability.