DPDS: A DPDK-Based Packet Delayer and Spacer

2026-06-16

AI Summary

This work addresses the challenge in network link emulation where variable delay often introduces excessive latency or packet reordering. To mitigate these issues, the authors propose an adaptive delay correlation mechanism based on DPDK that dynamically adjusts inter-packet delays. The approach effectively avoids both over-delay and packet reordering while simultaneously supporting bandwidth limitation, traffic shaping, rate limiting, and two distinct packet loss models. Experimental results demonstrate that the system achieves zero-packet-loss throughput of 95 Gbit/s under constant delay and 85 Gbit/s with 3 ms jitter on hardware, significantly outperforming NetEm and MoonEm. The study also provides practical configuration guidelines for the critical half-life parameter governing the adaptive behavior.

Abstract

In this paper we tackle the problem of adding varying delay to packets for link emulation. Naive approaches either add more delay than desired or cause packet reordering, both of which are undesirable. We develop adaptive delay correlation, which adds positively correlated delays to packets efficiently. It takes a mean delay and standard deviation (jitter) as input, as well as a half-life period to control the delay dynamics. We investigate the accuracy and dynamics of the resulting packet delays with and without bandwidth limitation. As a result we give a recommendation for the configuration of the half-life period. We implement adaptive delay correlation in a DPDK-based packet delayer and spacer (DPDS), investigate its performance on hardware, and compare it with the widely used link emulator NetEm and the recently developed DPDK-based emulator MoonEm. DPDS outperforms both of them with a zero-loss throughput of 95 Gbit/s for constant delay and, with spacing enabled, 85 Gbit/s for varying delay with 3 ms jitter. Further, DPDS supports packet reordering with zero-loss throughputs of 73 Gbit/s and 58 Gbit/s for constant and varying delay, respectively, as well as policing and two packet loss models.

Problem

• packet delay
• link emulation
• packet reordering
• jitter
• network emulation

Innovation

• adaptive delay correlation
• DPDK
• packet delayer
• link emulation
• jitter control