Optimizing Anycast Performance: A Comparative Study of Root DNS and CDN Latency

Abstract

Anycast is a critical technology enabling efficient content delivery across the internet, particularly for services like DNS and Content Delivery Networks (CDNs). This study investigates latency and path inflation challenges faced by these services, examining whether the significant investments in anycast infrastructure have truly optimized user performance. Using a global dataset comprising RIPE Atlas probes, recursive resolver traffic, and proprietary CDN latency traces, our experiments reveal that root DNS latency contributes less than 1% to overall page load time due to effective caching (average latency: 8 ms/page). In contrast, CDNs exhibit a 30–120 ms latency reduction when deploying additional anycast sites. Despite path inflation (observed in 20% of CDN users), CDNs achieve better user performance due to strategic deployment. Our findings highlight the need for application-specific anycast optimization.