Stratum CAKE — ns-3 vs native Linux cross-stack validation dataset

Two like-for-like measurements validating the CAKE client of Stratum (a QoS substrate for the ns-3 network simulator) against the original Linux kernel implementation, sch_cake. In each, both stacks are configured or driven identically and the simulator is compared to the kernel on real hardware. host-isolation-fairness (measured 2026-06-13): CAKE triple-isolate host-fair share under closed-loop TCP at the (4-flow, 1-flow) split (100 Mbit, RTT ~40 ms). With both stacks matched (4 MB socket buffers, segmentation offload off), native Linux gives the many-flow host a 0.533 share and deterministic ns-3 gives 0.647; injecting the hardware interrupt/softirq timing jitter the simulator lacks drives its share down to bracket the Linux value (a seed ensemble around 0.55, floor near 0.52). autorate-ingress (measured 2026-06-17): CAKE autorate-ingress capacity estimation on a 10-to-20 Mbit/s stepping train fed identically to both stacks. ns-3 and Linux agree on the inferred capacity to about 1.5% and re-adapt with the same window-close cadence; the ~1 s post-step lag is a property of the workload, not CAKE (bursty traffic re-adapts in ~0.2 s on real Linux). Ground truth is the Linux kernel (net/sched/sch_cake.c); the ns-3 reference points are reproducible from the public Stratum substrate (github.com/digitalities/stratum-ns3). Data, notes, and figures: CC BY 4.0; harness scripts: GPL-2.0-only.