Offloading Cloud Network Services at Production Scale with SONiC DASH SmartSwitch
Abstract
To support stateful cloud network services, Microsoft Azure has operated several generations of offloading solutions over the past decade. While these systems improved performance, operating them at hyperscale revealed three persistent lessons: (i) overly flexible programming models hinder hardware acceleration, (ii) appliance-style DPU pools inflate physical footprint and complicate deployment, and (iii) vendor-specific SDKs slow down service iteration. We present SONiC DASH SmartSwitch that addresses these lessons with three key designs: (1) the DASH pipeline as an immutable and hardware-friendly programming model; (2) the uni-box SmartSwitch that converges NPU and DPU resources within a single T1 switch; and (3) a community-driven development model with P4 behavior specifications. SONiC DASH SmartSwitch has been deployed in Microsoft Azure at scale. It achieves 1.53Tbps throughput, 19.2M CPS, and 256M concurrent connections for network services, while improving power efficiency by ~1.8× and space efficiency by ~2.7× compared to the previous generation.