🚀 go-pugleaf

> ...some basic questions about TCP/IP running over RS232?

The first question is "what do you mean by RS-232"?  Strictly speaking,
RS-232 refers only to the physical and electrical characteristics of a
serial line.  Are you referring to asynchronous or synchronous lines?

> 1) does anyone have TCP/IP running over RS232 under BSD4.[123] or
> SYS V.[02]?

Neither 4.1BSD nor System V have any form of networking that comes
"standard".  There are a couple of implementations of TCP/IP over
asynchronous serial lines for 4.2BSD and 4.3BSD.  The most popular (and,
from what I know, best) one is Rick Adams' implementation.  It is compatible
at the link level with 3Com's UNET.  The latter used to be available from
3Com; it could be dropped into 4.1BSD and has been modified to work on
System III (and probably System V).  However, I don't think they offer it
any more.

> 2) if you have got TCP/IP running over RS232, what hardware are you using?
>    what software are you using? were there any *major* problems in getting
>    it all to work?

Rick's code works on most (if not all) asynchronous multiplexer boards for
VAXes and, I believe, on the Sun asynchronous multiplexer.  (It probably
works on the CCI Power 6/32 and is, I believe, being adopted by other
manufacturers.  I don't know which manufacturers offer it as part of their
standard UNIX; Sun does not.) It pretty much drops in and goes, once you've
modified the 4.2BSD IP code to permit multiple interfaces to share the same
network number (Rick's code comes with those modifications).  I can't speak
for 4.3, but I believe it works there as well.

> 3) does anyone know what differences there are between BSD4.1, BSD4.2 and
>    BSD4.3 as far as TCP/IP networking over RS232 is concerned? more to the 
>    point, does anyone know if it works under all of these flavours?

It works very differently between 4.1BSD and 4.[23]BSD, since 4.[23]BSD has
networking built in and 4.1BSD doesn't.  Rick's code won't work under 4.1,
since 4.1 doesn't have the 4.[23] networking code, but it should talk to
a 4.1 system running UNET.

> 4) i heard that it was not possible to configure more than one serial line
>    per machine, so things like star networks are out. is this true, has
>    anyone out there done it?

This is completely untrue.  We used Rick's code at CCI and used a VAX
running 4.2 as the hub of a star network; we used CCI machines running UNET
as the hub of other stars.

> 5) i also heard that it is not possible to run TCP/IP and users on the same
>    RS232 card. is it true that the device that you use to support TCP/IP
>    over RS232 has to be used for this purpose exclusively?

This is also untrue; the particular asynchronous *line* which is used for IP
cannot be used for anything else (obviously), but the other ports on the
multiplexer card can be so used, either with Rick's code or UNET.

> 7) are there any useful documents on how to do it, or any useful references?

Ask Rick Adams about where to get his code; his email address is seismo!rick
("seismo" is "seismo.CSS.GOV" on the ARPANET, and is a USENET backbone site
and so has a fair bit of UUCP connectivity; the best European path is
probably through "mcvax").

	Guy Harris