AWS Replaces 30-Year-Old Fat-Tree Network Design With Flat Random Graph Architecture

Amazon Web Services has developed a new data center networking system called the Resilient Network Graph (RNG), replacing the decades-old hierarchical 'fat-tree' model that has dominated cloud infrastructure. The traditional fat-tree architecture routes data through multiple layers of switches, creating bottlenecks that can strand up to 60% of network capacity. RNG uses random graph theory to connect routers directly, eliminating intermediate aggregation and spine layers that added latency and consumed power. The shift results in 69% fewer networking devices, up to 33% higher throughput, 40% lower power consumption, and cost savings ranging from 9% to 45%. AWS principal applied scientist Giacomo Bernardi noted that while the concept existed in academia, practical deployment was previously blocked by unmanageable cabling complexity and insufficient switch memory.