Expanding across time to deliver bandwidth efficiency and low latency

TL;DR

Opera is a dynamic datacenter network that combines expander-graph properties with time-varying circuits to achieve low latency and high bandwidth efficiency, supporting modern application demands.

Contribution

This paper introduces Opera, a reconfigurable network design that maintains expander properties over time to optimize both latency and bandwidth in datacenter environments.

Findings

Supports low-latency traffic with flow completion times similar to static topologies.

Delivers up to 4x the bandwidth for all-to-all traffic.

Supports 60% higher load for datacenter workloads.

Abstract

Datacenters need networks that support both low-latency and high-bandwidth packet delivery to meet the stringent requirements of modern applications. We present Opera, a dynamic network that delivers latency-sensitive traffic quickly by relying on multi-hop forwarding in the same way as expander-graph-based approaches, but provides near-optimal bandwidth for bulk flows through direct forwarding over time-varying source-to-destination circuits. The key to Opera's design is the rapid and deterministic reconfiguration of the network, piece-by-piece, such that at any moment in time the network implements an expander graph, yet, integrated across time, the network provides bandwidth-efficient single-hop paths between all racks. We show that Opera supports low-latency traffic with flow completion times comparable to cost-equivalent static topologies, while delivering up to 4x the bandwidth for all-to-all traffic and supporting 60% higher load for published datacenter workloads.