point-to-point networks for PIs?

[Mark Bartelt]

One of the people in our group has a pair of 4D20s, one in his office
and one at home (nice home computer, eh?).  He's getting rather tired
of lugging things back and forth via cartridge tape, so we're looking
for alternatives.

One can obtain a point-to-point leased line from TPC for a reasonable
cost (well, how reasonable depends on the type of line), but we need
to find out what sort of PI hardware/software support we can get.

What we'd like to do is run the line at 56kb (or possibly 19.2 if the
cost of the 56kb line is too prohibitive), using some type of plug-in
synchronous (or async?) serial board in the SGI boxes.  Unfortunately,
our salesguy says that SGI doesn't provide anything along these lines.
So it looks as if we'll need to look at third-party vendors.

Does anybody have a recommendation (or non-recommendation, for that
matter) for who we should be talking to?  We'd clearly want someone
who not only sells the board, but also provides a (working) device
driver that we could configure into the kernel.  What about modems?
Anybody have any favourites?  (I think that if you get a 56kb line
from Bell Canada, cost of the modems is bundled in, so this question
may be irrelevant.)

Once the hardware and driver are in place, how about network support?
I presume that what we'd want to do is use PPP (or maybe SLIP?) to
run the point-to-point connection, and run gated in the office-end
PI, which is also connected to our ethernet.  Would all this be both
necessary and sufficient to provide all the capabilities we'd want
(e.g. telnet/ftp, plus NFS mounts (yeah, we *know* it'd be slow!))?

Theories about what might/mightn't work are welcomed, but what we'd
really like is to hear from someone who's actually done this.

As usual, thanks in advance.

Mark Bartelt                                           416/978-5619
Canadian Institute for                        mark at cita.toronto.edu
Theoretical Astrophysics                      mark at cita.utoronto.ca