P4R: Scaling Stateful Network Testing and Trace Replay with Nanosecond-level Accuracy
Resumo
As network speeds transition to 100 Gbps and beyond, traditional software-based traffic generators face significant performance and accuracy bottlenecks due to CPU and PCIe limitations. While programmable switch-based testers have emerged to provide line-rate throughput, most current solutions are either limited to stateless traffic generation or rely on simplified stateful models, such as “stop-and-wait” mechanisms with static one-packet windows. This paper presents an evolved version of P4R (P4 Replay), an open-source framework designed for high-fidelity stateful network testing on programmable ASICs. P4R overcomes previous design constraints by introducing a dynamic window management system for TCP connections, enabling more realistic flow emulation compared to fixed-window architectures. Furthermore, P4R implements a dual-mode trace replay engine capable of reproducing pre-captured PCAP files with nanosecond-level timing accuracy or user-defined throughput. Supporting client, server, and a unique internal self-testing mode, P4R allows for the evaluation of complex P4 applications and external network functions at line-rate. We demonstrate that P4R bridges the gap between synthetic traffic and realistic network experimentation, providing the community with a versatile and precise tool for modern networking research.
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