SLIP
2007-12-25 8:20:00
I have to get X sessions running over modems between PCs (MS Windows) and
SPARCs. Since we currently run PC-NFS on ethernet internally, SLIP seems
natural; however:
o SLIP is rumored to only run up to 9600 baud or so on the Sun side.
o I seem to remember other transports having been mentioned that were
more robust..
===========================================================================
Suggestions and comments on SLIP or other transports:
From: blymn@mulga.awadi.com.AU (Brett Lymn)
> o SLIP is rumored to only run up to 9600 baud or so on the Sun side.
>
Suns have a problem with their on-board serial ports, they do not have
input flow control lines. Hence they can have the input buffer
overrun. We have had a sun running a fixed slip link at up to 38400,
there were some silo overflow errors but it seemed to work fine.
If you get a terminal server or an sbus serial card that had input
flow control then you should not have any problems.
> o I seem to remember other transports having been mentioned that were
> more robust..
>
PPP will perform error checking on packets at a much lower layer than
slip which means it wins if the number of bad packets you get is high.
PPP also has some advantages when you are using dial-up lines. The
downer with it is that there is not a PPP driver for PC-NFS, there is
a SLIP driver though.
---
From: David Fetrow <fetrow@biostat.washington.edu>
If all you want is Xsessions, SLIP is rediculous. There are optimized
serial-line Xwindows protocols (NCD has one, X11r6 will have a standard one
that everyone will use, etc.) that will drive Xwindows a lot faster. Combined
with a PC-centric X11 windows manager and local fonts; it can get almost
snappy. Note that it doesn't speed things up on these to use on-the-fly
compression since that's already in the protocol.
If you still want SLIP there are some things that can go faster. SLIPPER
and CSLIPPER are packet drivers that can go faster. Combined with Geoff Arnolds
packet driver shim (which makes a SLIPPER-style packetdriver look like a SUN
PC-NFS driver) you should be able to go quite quickly. In this case the
higherspeed modems (that use on-the-fly-copmpression) will go faster.
It's all available from the real archives or even ftp.biostat.washington.edu
(via anonymous ftp) in /pub/msdos/network.setups
---
From: Jim Lick <jim@pi-chan.ucsb.edu>
> o SLIP is rumored to only run up to 9600 baud or so on the Sun side.
Bzzt. Can run at any speed the serial port can (usually up to 38400).
> o I seem to remember other transports having been mentioned that were
> more robust..
More robust, but SLIP is still good for the job. SLIP with VJ header
compression (aka CSLIP) is even better.
---
From: mikem@ll.mit.edu (Michael J Maciolek)
Don't believe the rumors. SLIP runs easily at 19200, and even at 38400, you'll
only drop bits occasionally (and IP error detection/correction will make up for
that) if you happen to be generating a lot of higher priority interrupts (like
heavy disk i/o).
If you could actually sustain 38.4kbps, your X performance might be adequate
most of the time (except for bitmaps, which would still be pretty bad). But
you'll need a very fast modem to sustain 38.4k.
My recommendation is to try SLIP with a null-modem cable first, and see how
it performs. Set your line speed to 19.2k - it'll give you an idea of how
fast you'd run with a v.32bis/v.42bis modem.
---
From: bert@penril.com (Bert Robbins)
I have attempted to use PC-NFS' SLIP capability and found that
when connected via a null modem cable, as defined by Sun, it
works great at 9600 baud. But, when attempting to use PC-NFS'
SLIP over modems it is very slow and looses pakets.
I also had a problem when using modems with in.routed where the
routes were not being added properly and were disapearing at
random.
And, yes PC-NFS only allows you to enter 4 digits for the line
speed, so you can only go as high as 9600.
---
From: blenherr@analytics.abb.com (Bill Lenherr)
I have been fighting with a PC-NFS 5.0 SLIP installation for some
time now. I am trying to SLIP my 486 at home into the 690mp here
at the plant. I have gotten it to work if I connect in interactive
mode and su before initiating slattach but this is not good enough.
As you mentioned, the connection also appears very slow even though
it is a 9600 baud V.32bis error correcting connection. I wanted to
run SLIP and to get NFS and then as required run NCD's PC-Xview to
run X applications. This is just too slow for that as I have it
installed ! My next venture might be trying PC-Xview Remote which
claims 10 times the compression and can do higher speeds. This eliminates
using NFS though ! I am also keeping my eye open for ISDN boards
for PC's since we have ISDN available.Let me know what you do and
feel free to throw questions this way.
---
From: grevemes%ccmail@TACOM-EMH1.Army.Mil
I used to run slip on a sun3 at 38400. Currently I am running PPP at
24Kbps. (Actually the connnection to the modem is fixed at 38.4K and the
modem is running at 24K).
If you want to run the connection faster than 38.4K (the fastest supported
speed on stock sun serial ports), you have to get the High-Speed Serial
Interface (HSI) board. This board costs roughly $1200. I haven't bought
one yet.
---
=============================================================================
and on X servers:
From: David Fetrow <fetrow@biostat.washington.edu>
If all you want is Xsessions, SLIP is rediculous. There are optimized
serial-line Xwindows protocols (NCD has one, X11r6 will have a standard one
that everyone will use, etc.) that will drive Xwindows a lot faster. Combined
with a PC-centric X11 windows manager and local fonts; it can get almost
snappy. Note that it doesn't speed things up on these to use on-the-fly
compression since that's already in the protocol.
---
From: bilkerla@pluto.crd.ge.com (Lawrence A. Bilker)
you may want to check out PC-Xview and PC-Xremote for the PC. Its pretty fast
and supports up to 19.2K. You don't need any special modems since the software
on the two ends does compression/error checking for you. The package includes
host software for almost any platform. PC-Xview comes from NCD. Their
technical support is good too.
---
From: rg@issi.com (Ron Gilmer)
Jim, I use PCXView and PCXremote fom NCR which I purchased from Cindy at
UNIX CENTRAL. Seems like the price was $199.00.
It will connect at 14,400 modulation and 19,200 dte.
I run the twm window manager and find the speed acceptable but not lightning.
If You need further info let me know.
---
From: dougj@iplab.health.ufl.edu (Doug Jones)
Who's x-windows are you using on the Windows side
We use NCD PC-Xview fro dos and windows, you can get a nifty product
called xremote and xremote host.
It sets up the serial connection, starts the compressed protocol and
the x-server software.
You can use any serial speed up to 56Kb
On the Mac side we use Exodus, and a Mac-PPP driver for MacTCP
I got the driver from sumix-aim.stanford.edu. And the ppp software for the
sun from ftp.morningstar.com
Hope this helps.
---
From: shevett@sparc.bighouse.unipress.com (Dave Shevett)
Whee! This one's easy :) - XRemote from Visionware will do it. Run
Xvision (a very robust Xserver for MSwindows), with the Xremote add-on
products. Whatcha do is run a little utility called 'visionlink', that
dials into your sparc, and then you run 'xinitremote'. 'xinitremote'
talks back across the link to your Xserver and starts up an Xterm
(or whatever you want).
The link is compressed, and doesn't have the overhead of SLIP (you're not
moving TCPIP packets - it's using NCD's protocol, which is much more
efficient).
Okay, i'm biased cuz our company sells the product. It's not a PD
solution, but we have many customers running it happily. We've run it
over 19.2kb modems and it runs pretty damned well...
---
From: Craig Kruck <kruckc@hitachi.hitachi.com>
If you are looking for X emulation packages which run on the pc remotely
(over modems) there are a couple of vendors which produce such applications.
Both Hummingbird (exceed/Xpress) and NCD (PC-Xview) have PC X applications that
run over the ethernet (tcp/ip) and over phone lines. I'm in the process of
testing the Hummingbird product and I have heard NCD has a new release. The
last time I played with PC-Xview I got mixed results. As long as you are not
dealing with graphic intensive applications, performance is acceptable. But if
your applications deal with lots of graphics, watch out! You're users will not
be happy campers.
---
From: kbs@huey.mis.semi.harris.com (Ken Stoddart)
I'll assume from your message that you are only interested in using
remote X-clients and that you do not intend to perform file transfers
etc.
We've started to used PC-Xview X-window software by NCD. NCD sells
PC-Xremote, their own serial line protocol that runs at whatever speed
your modems support. This software is tuned to get the maximum
throughput on transmission of X-window commands (it strips off
unnecessary baggage etc.). NCD is also claiming that the xremote
protocol is going to be included in X11R6 since it is fast becoming a
serial X standard (due to the improved throughput etc.).
I evaluated PC-Xview from home over a 14400 carrier modem and had acceptable
use of X from Microsoft Windows 3.1. It will never be as 'peppy' as sitting
at the graphics head, but it was usable. It supported both the olwm and
OpenWindows 3.0 tools, but the overhead made their use unsatisfactory. When
I run pure X, say using twm, and standard x-tools, it worked fine.
NCD is about to release PC-Xware for Windows in the next few weeks. This
is a full 32-bit implementation which promises better performance on 32-bit
PC's.
---
From: nlf@aluxpo.att.com
look at Serial Express from Hummingbird.
look at Xremote protocol from either PC Xview (from NCD) or Xvision
They all work. They are all significantly faster than SLIP.
>From what I've heard from others the Xvision is a little more robust
for graphics than the current PC Xview and the Serial Express protocol
is about twice as fast as the Xremote protocol.
---
From: Roland Hamblin EOS <rolandh@eos.co.uk>
Since you are already running PC-NFS, how about running PC-Xview for you X
sessions?
---
Our effort is still underway at a reasonable priority. We'll be looking at
the X packages to see what works and I'll furthur summarize on the results.
Hummingbird will be first, since it is rumored to support telnet as well.
Thanks to all for the responses.
Jim
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