> Jacobson, V. 1992, "  Design Changes to the Kernel Network Architecture
> for 4.4BSD, 4.4BSD Class, Berkeley, Calif., May 1992.
>
> Possibly available as
> 	http://www.alkyltechnology.com/nbsd/vanjacobson1992.pdf

The PDF file is available again.

The short summary is that it's pity to use software initated interrupt
(netisr) to crank networking protocol stack.  It's now norm OS has
(appropriately scheduled) light weight threads to multiplex protocol
stack and network interface activities.  It's worth noting that Sequent
had muti-processor aware MT-safe TCP/IP procotol stack which was
a derivate from Spider System's STREAMS (IP procotol stack itself
was 4BSD.  PLS don't confused with Lachman/Interactive's or SVR4
STREAMS. They were a doomed product...)

Toru Nishimura/ALKYL Technology