Abstract
This paper presents link 'em, an open source link emulation bridge for reproducible networking research. While reproducibility is one keystone of good research, most available link emulators are lacking crucial features or are prohibitively expensive. Link 'em is a Raspberry Pi-based layer-2 bridge that runs an extended version of netem in conjunction with a trace database to achieve reproducible link emulation. By invoking our novel packet loss module, which builds upon sagemath and NetfilterQueue, more sophisticated packet loss models can be used in addition to netem's existing ones. The proposed demonstration verifies the achieved reproducibility. This is done by showing the effects of a model-based link emulation via netem and a trace-based emulation using our link 'em bridge on a video live stream, compared to a pre-captured reference stream.