austin@cs.widener.edu (Jeff Austin) (12/08/90)
A few days ago, I posted an article about the feasibility of
establishing a VAX-to-PC connection using TCP/IP protocol. The
connection was to be maintained over serial dialed line, much
like DEC's DECnet-DOS using Asynchronous DDCMP. Nevertheless,
I received MANY replies, and the common solution was to use SLIP
protocol. Here's a summary:
TCP/IP can be run over serial lines (both dialed and
direct) by using the SLIP protocol. SLIP is an acronym
for Serial Line Internet Protocol - an IP protocol that
was designed for asynchronous terminal lines. So, for
the VAX-to-PC solution, one would need SLIP software on
the VAX host AND a PC-based package. To configure the
circuit, the VAX must load the driver for SLIP and start
it on a specific terminal port (or ports). Nevertheless,
SLIP ports are also configured with an appropriate IP
address. Once the ports are ready, the PC user simply
connects to the VAX SLIP port (either via a dial modem
or direct connect) and then starts the PC SLIP software.
After SLIP "waves it's magic wand" (and a few seconds
pass by), the circuit will be active. Then, the applic-
ations part of TCP (TELNET, FTP, PING, etc) can be
run over the line. Pretty neat, eh?
Now, there are several vendors that can be used for the
SLIP drivers. The two I looked into were The Wollongong
Group's "WIN/TCP for VMS" package and FTP Software's
"PC-TCP" package for MS-DOS, both configured with the
SLIP drivers. However, I'm sure other vendors support
SLIP as well! For those of us who don't like to pay
for software, I have received responses for PD versions.
On SIMTEL, in pd3:<misc.ka9q>, you may find something.
Also, NCSA TELNET should have SLIP capability and
the Universitys of Maryland and Wisconsin offer TCP/IP
packages that support SLIP. Might have to pay a little.
Carnegie-Mellon also has a package.
So, for anyone who wants their PC to talk to a VAX
over telephone (or hard-wired) non-ethernet lines, SLIP
is the way to go. Just find the MS-DOS SLIP and a
suitable VMS SLIP package and do it! Oh yeah, remember
that SLIP is not just a MS-DOS to VMS package! It
also (actually more commonly) supports PC-to-UNIX
circuits. I'd imagine that wierd things like MAC-to-UNIX
are equally possible via SLIP (assuming you can find
the right software).
Many thanks to Bill, Ian, Frances, Eric, Michael, and
Reginald!
Jeff
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| Jeff Austin - Widener University, Chester PA | The Computer Rule of Thumb: |
| austin@tattoo.cs.widener.edu | "When in doubt, reboot!" |
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