From: rich@grebyn.com (Richard Lawrence)
Subject: Re: HELP: VAX to PC Communications questions?
Keywords: VAX VMS BRIDGE ROUTER
Organization: Grebyn Timesharing
Date: Wed, 23 Dec 1992 07:03:54 GMT

In article <BznHHv.A33@world.std.com> dlowe@world.std.com (Miller Lowe) writes:
>Here is the current cabeling picture;
>
>  <DEC halve deleted for brevity, where PC#1 is>
>  <-------+--------+------------------------+----------------->
>          |                                 |IPX = FEEDBFOO
>      /---+---\                       /-----+------\
>      | PC #2 |                       |  NetWare   |
>      \-------/                       |v3.11 Server| "MOTHRA"
>                                      \-----+------/
>                  IPX & TCP/IP              | IPX = FEEDBOFF
>   <-----------+----------------------------+------------------>
>               |           LAN 'C'                     Other Netware
>           /---+---\                                   Servers  -->
>           | PC #3 |                                   & LANs
>           \-------/
>
>I have connected PC #1 and logged into the NetWare Server MOTHRA
>with no problem and according to the terminal program (which has a
>LAT driver) documentatiom I should have no problem logging onto the
>VAX systems from PC#1 or PC#2.  I haven't installed the terminal
>program yet.

Yes, this should work fine.

>BIG QUESTION #1:
>----------------
>How do I get PC #3 to process DECNET packets through the NetWare
>server MOTHRA.  While MOTHRA will pass TCP/IP or IPX I do not think
>that it will pass DECNET even though it uses 802.3 Ethernet.

If the Novell server has two interfaces in it and is attached to both
nets, then I assume it is routing. If so, you have a problem. See
below.

>
>Must I put some sort of router attaching LAN 'B' and LAN 'C' that will
>route DECNET packets and keep the LANs withe their respective IPX names?
>I have put a PCbridge between them but as expected I get Router errors
>off of the MOTHRA internal router.

Gack. The only problem with this idea is the biggie: you can't route
LAT (no, I'm not kidding). It can only be bridged. There are a couple of
good reasons for this, but it often gives people headaches in a mixed
protocol environment. Keep in mind that LAT is a streaming protocol
designed for asynchronous devices with a very low timeout ceiling. Its
strong suite is NOT interopability with other protocols (but it does a
great job of being economical of network resources by such features as
combining multiple jobs/sessions in a single packet...)

>BIG QUESTION #2:
>----------------
>Is there a public domain routing program that will perform this with
>a PC like PCROUTE.  Speed is not really an issue at this time and I
>have lots of spare Western Digital/SMC 8003 family NICs.

There's none that I know of. I've often wondered why somebody doesn't do
some sort of tunneling system, but I guess the low timeout limits are a
factor.

>I would like to make the VAXen an available resource to all PC's on
>the network.  There are a couple more servers and Netware Routers off
>of the page that I did not bother to draw.

If you can't beat 'em, join 'em. VAXs have the ability to speak TCP/IP
with the best of them, of course. Or, you could see how feasible it is
to hook a terminal server (Xyplex comes to mind) up on the VAX side.

-- 
Rich Lawrence, Synoptics Systems Engineer  DOD#9630  rich@grebyn.com
     '92 Seca II "Yuri"  CI$:71101,2272  GEnie:R.LAWRENCE14
   216 years ago my government gave me certain inalienable rights.
     Since then, they've been trying to correct their mistake.