Something like a thermostat or a smart fridge – have you seen any? If so, please share with a video or two.
It doesn’t have as much to do with where the network stack is running, but that they’re leveraging hardware offloading. Their CPUs generally aren’t powerfull enough to switch packets at gigabit speeds let alone on many interfaces at gigabit or multi-gig speeds. Its by leveraging ASICs and maybe even some using FPGAs for hardware offload that they can switch packets at line rate. I understand how they do it, I still just find it kind of weird and cool.
I didn’t list HDDs as someone else had mentioned that already. I was just listing a few devices that weren’t mentioned in other comments yet.
Both really, you can’t fully offload to hardware if your kernel still requires an interrupt to pass the payload. That hardware most likely has userspace drivers.