AWS Replaces Fat-Tree Data Center Networks with Random Graph Theory, Cutting Routers by 69%

Mathematicians proved in the early 1990s that randomly connecting routers produces the most efficient, resilient network topology. It took AWS roughly 30 years to turn that result into production infrastructure. The company disclosed that Resilient Network Graphs (RNG), a flat network architecture based on quasi-random graph theory, is now the default for most new non-GPU AWS data center builds globally.

In a paper posted to arXiv, Giacomo Bernardi (principal applied scientist at AWS), Ratul Mahajan (University of Washington, Amazon Scholar), and Seshadhri Comandur (UC Santa Cruz, Amazon Scholar) describe it as the first large-scale production deployment of expander-based network fabrics. The numbers: 69% fewer networking devices, up to 33% higher throughput, and a projected 40% reduction in network equipment power consumption.

To understand why this matters, start with what it replaces. Traditional data center networks use a fat-tree topology: servers connect to…