BurstBalancer: Do Less, Better Balance for Large-Scale Data Center Traffic

Abstract

Layer-3 load balancing is a key topic in the networking field. It is well acknowledged that flowlet is the most promising solution because of its good trade-off between load balance and packet reordering. However we find its one significant limitation: it makes the forwarding paths of flows unpredictable. To address this limitation this paper presents BurstBalancer a simple yet efficient load balancing system with a sketch named BalanceSketch. Our design philosophy is <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">doing less changes</i> to keep the forwarding path of most flows fixed which guides the design of BalanceSketch and our balance operations. We have fully implemented BurstBalancer in a small-scale testbed built with Tofino switches and conducted both large-scale event-level (NS-2) and ESL (electronic system level) simulations. Our results show that BurstBalancer achieves 5% <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 35% smaller FCT than LetFlow in symmetric topology and up to 30× smaller FCT in asymmetric topology while 58× fewer flows suffer from path changing. All related codes are open-sourced at GitHub