I would assume that the TCP state would be part of the "networking service" that is isolated from my application. As such, I'm assuming the more complicated si

I would assume that the TCP state would be part of the "networking service" that is isolated from my application. As such, I'm assuming the more complicated situation there. That said, I don't make too big of a defense of networking being a bad choice. At large, that is literally where you have to do distributed computing anyway; so, agreed a lot of it will be covered for a lot of applications. I was trying to stick to the examples others chose as I'm not really trying to "gotcha" to anyone. My main point was honestly more about how similar that is to how we are today. If you were in a microkernel, is it any easier? Because that is the original goal post here. I do further question why you'd want to do that for every subsystem interaction, and if you really want to have to redo all kernel context swaps and local message passes if something went wrong locally.