TurboNet: Faithfully Emulating Networks with Programmable Switches

Faithfully emulating networks is critical for verifying the correctness and effectiveness of new networking-related designs. Existing network experiment platforms either cannot faithfully emulate functionality and performance of production networks or cannot scale well because of cost limitations. In this paper, we propose TurboNet, a new network emulator that leverages one programmable switch to enable faithful emulation of both network data plane and control plane. For data plane emulation, we present a series of key designs such as port mapper, queue mapper, and delayed queue to emulate network topologies and performance metrics with high flexibility and accuracy. For control plane emulation, we support static routing configurations, distributed routing agents, and the centralized routing controller. Meanwhile, we provide API for operators to simplify network emulation tasks. We implement TurboNet on a Tofino switch. The evaluation results show that: (1) TurboNet can flexibly emulate various topologies such as the 8-ary fat-tree on the data plane and support about 200 BGP agents with 25% CPU usage on the control plane; (2) TurboNet can accurately emulate different network performance metrics, including 400Gbps line-rate background traffic injection, as small as 10 link loss, and microsecond-level to millisecond-level link delay.