Build Limitless Network with Smart Switch

Author: Prince, SONiC Team, Microsoft Collection: 2023 Global Summit - Networking

Summary

Microsoft proposes a Smart Switch architecture that integrates a 12.8 terabit switching ASIC with 8 DPUs into a single 2RU chassis, creating a powerful disaggregated network appliance for data center deployments. The Smart Switch augments traditional SmartNIC capabilities by pooling DPU resources at the switch level, enabling SDN policy offloading from server-side VFP (Virtual Filtering Platform) to DASH-enabled DPUs hosted within the switch. This approach delivers lower power, lower latency, and higher throughput compared to per-server SmartNIC deployments.

The presentation focuses heavily on high availability (HA) as a critical feature for Smart Switch deployments. The HA design uses ENI-level (Elastic Network Interface) active/standby pairing across DPUs on different Smart Switches, with flow synchronization ensuring existing connections survive DPU failures. The NPU detects DPU failures in fractions of a second using BFD offloading and can redirect traffic via VXLAN tunnels to remote DPUs. SONiC runs on both the NPU and DPU sides, with a stripped-down version on the DPU to conserve memory for connection tracking.