The best one seems to have been the 3Com stack, which
puts IP in the
kernel and TCP in a daemon. By the way, this implementation is also
where SLIP seems to have originated.
As much as I love all the nostalgia, and as cool as SLIP was, if I never
have to experience the pain of trying to run TCP/IP over a modem again,
I'll be happy. For me, SLIP was just not worth it. Too much overhead
when bandwidth was too precious. A dial up terminal emulator was a
better answer in my experience.
Don't get me wrong, SLIP was cool. Modems were slow.