pending changes for TOE support

[David Christensen]

> >> + * The TOE API assumes that the tcp offload engine can offload the
> >> + * the entire connection from set up to teardown, with 
> some provision
> >> + * being made to allowing the software stack to handle 
> time wait. If
> >> + * the device does not meet these criteria, it is the 
> driver's responsibility
> >> + * to overload the functions that it needs to in 
> tcp_usrreqs and make
> >> + * its own calls to tcp_output if it needs to do so.
> >>
> >> While I'm familiar with TCP, I'm less familiar with the 
> scope of what cards
> >> support for TOE.  Do we know of any cards that are less 
> capable than the
> >> chelsio card in this respect, or are they all sort of 
> on-par on that front?
> >> I.e., do we think the above eventuality is likely?
> > 
> > I don't have any way of knowing. I think it is probably safe to say
> > that any vendors that don't meet that criteria now will in 
> the future
> > as transistor density increases.
> 
> There are cards (or at least I've heard talk of this) that do partial
> TCP offload - that is the connection setup and teardown are handled by
> the operating system and that only data transfer is offloaded.  I'm in
> the wrong country to chase down details on this ;(

You are referring to Microsoft Chimney architecture which would be
supported by all TOE adapters that operate under Windows (our 
NetXtreme II controllers included).  There are IP issues related to
a chimney style implementation that would likely preclude their use
under FreeBSD including passing TCP state information between the
host OS and the controller among them.

Dave