The Stellar Transformation: From Interconnection Networks to Datacenter Networks

TL;DR

This paper introduces the stellar transformation, a method to convert well-studied interconnection network topologies into new, efficient dual-port server-centric datacenter network topologies, significantly expanding design options.

Contribution

The paper presents a generic transformation technique that creates new datacenter topologies from existing interconnection networks, along with routing algorithms and performance evaluations.

Findings

GQ* outperforms FiConn and DPillar in throughput and latency

The transformation yields networks with good load balancing and fault tolerance

Substantial improvements over existing datacenter network topologies

Abstract

The first dual-port server-centric datacenter network, FiConn, was introduced in 2009 and there are several others now in existence; however, the pool of topologies to choose from remains small. We propose a new generic construction, the stellar transformation, that dramatically increases the size of this pool by facilitating the transformation of well-studied topologies from interconnection networks, along with their networking properties and routing algorithms, into viable dual-port server-centric datacenter network topologies. We demonstrate that under our transformation, numerous interconnection networks yield datacenter network topologies with potentially good, and easily computable, baseline properties. We instantiate our construction so as to apply it to generalized hypercubes and obtain the datacenter networks GQ*. Our construction automatically yields routing algorithms for GQ* and we empirically compare GQ* (and its routing algorithms) with the established datacenter networks FiConn and DPillar (and their routing algorithms); this comparison is with respect to network throughput, latency, load balancing, fault-tolerance, and cost to build, and is with regard to all-to-all, many all-to-all, butterfly, and random traffic patterns. We find that GQ* outperforms both FiConn and DPillar (sometimes significantly so) and that there is substantial scope for our stellar transformation to yield new dual-port server-centric datacenter networks that are a considerable improvement on existing ones.