From: dorner@pequod.cso.uiuc.edu (Steve Dorner)
Newsgroups: comp.sys.mac.comm
Subject: MacSLIP and VersaTerm SLIP, a Mini-Review
Date: 8 May 92 14:16:23 GMT
Reply-To: s-dorner@uiuc.edu (Steve Dorner)
Organization: University of Illinois at Urbana-Champaign


INTRODUCTION

After a long wait, I've finally seen two SLIP LAP's for MacTCP.  One is
MacSLIP by Rick Watson, and the other is VersaTerm SLIP by Lonnie Abelbeck.
The former is yet to be released, while the latter is available by
purchasing or upgrading the VersaTerm terminal emulator.
*** MacSlip is now released.  See the announcement after this message.

Before I go on to compare the two products, I want to give you the good
news.  Both products are easy to install and setup, and both work just
fine.  You're unlikely to go wrong with either product.  While the products
are quite different, most of the differences are matters of taste rather
than function.

I've been using MacSLIP for a couple of months.  I find it quite nice for
Eudora, Fetch, and the like.  My modems (2400 baud MNP-5) are too slow for
SLIP to be useful for terminal emulation, at least with my dialins, which
don't do compressed SLIP.  I've only used VersaTerm SLIP a few times,
though I plan an extended test sometime soon.  I've encountered no problems
with it in my limited testing.
*** I have used Versaterm Slip a lot.  I had problems with the transmit 
timer.  I recomend you turn it off by setting it to 0.  Otherwise it 
works great.

WHAT IS a "MacTCP SLIP LAP"?

It's an extension that allows MacTCP to work over a phone line, allowing
you to use any MacTCP application over your modem, if you have the right
dialins.

INSTALLATION

MacSLIP consists of two parts.  The SLIP LAP itself, a CDEV (slipcdev)
that's used to configure the LAP.  To install, you drag the LAP and the
CDEV onto your system folder (system 7).  It also comes with a NetStat
application that's useful if you like looking at TCP statistics.

VersaTerm SLIP consists of three parts.  There is the SLIP LAP, a CDEV with
no user configuration items in it, and an application (VersaTerm AdminSLIP)
that does the configuration.  These various pieces are all installed by an
installer script, which also installs MacTCP.  Of course, there's other
stuff with VersaTerm SLIP, too, like VersaTerm :-).

Comment: I didn't like the fact that VersaTerm SLIP installer installs its
own copy of MacTCP; I think I'd rather drag the files by hand (which is
possible).

CONFIGURATION

Once you've installed either product, you reboot.  Then you open the MacTCP
control panel, and select the LAP you want.  MacSLIP gives you just one
choice, "SLIP".  VersaTerm SLIP presents you with three different LAP's:
"SLIP (Modem)", "SLIP (Printer)", and "SLIP (Other)".  If you choose "SLIP
(Other)", you may specify the port in the VersaTerm AdminSLIP application.
*** this is not true for the software I tested.  It had only one SLIP
choice, you pick the serial port in the AdminSlip App.

You then configure MacTCP properly for your SLIP connection.  Either
product allows you to use Server or Manual addressing.  Another reboot is
done after you configure MacTCP.

To finish configuring MacSLIP, you open the slipcdev CDEV, where you can
set the serial port parameters, MTU, compression, logging and script
options.  The latter three are most interesting.

MacSLIP has three settings for CSLIP (compressed slip); Never, Automatic,
and Always.  Never means it will not use compressed SLIP, and always means
it will.  "Automatic" means that MacSLIP will use compressed SLIP if it
receives a compressed packet from the other end.

MacSLIP allows you to log the execution of your scripts, as well as the
opening and closing of the SLIP LAP.  This has proven to be very useful.
*** Versaterm Slip on the other hand has a simple terminal emulator
which allows you to see what happened during the Login Script.  You can
then continue interactively, something that MacSlip does not support.
On the other hand MacSlip's scripting facility is vastly superior to
Versaterm's facility

Finally, MacSLIP has a pretty reasonable scripting language built into it,
with variables, loops, timers, subroutines, etc.  It's hard to imagine a
dialin situation it couldn't handle.  On the other hand, it does take a
little work to write a script.

VersaTerm SLIP takes a different approach.  It has several several
configuration screens.  The inital screen lets you select a setup (you can
have different named setups).  A button takes you to the configuration
screen for the setup you've selected.

This next screen lets you specify serial port settings, phone number, MTU,
Compression, and to override some MacTCP parameters.  Compression is either
on or off; there is no "Automatic" setting.  It also contains a button for
configuring a modem, and one for a script.  The modem configuration allows
you to specify some strings to be sent to your modem before the connection
is attempted, and has a list of modems with preset strings.

The script configuration allows you to write simple scripts.  The idea is
that you send something, then wait some period of time for some other
string to appear, then send something else, etc..  One interesting feature
is that you can have the script read your IP address from the text sent you
by your dialin host; this would be useful for dialins where your IP address
varies from one connection to the next.
*** This feature is required for SLIP servers that assign the IP address
dynamically (either they pick it from a list or it is determined by
which modem in a telephone rotary you happen to get), and the SLIP
server does not support BOOTP.
*** this feature is important to me.  It turns out that MacSlip now
supports this function.  The current version has an odd bug, but the
readme file explains what you need to do to get this to work.  I use
it and its fine


Comments:
The configuration process for VersaTerm SLIP is pretty involved, with many
screens and subscreens.  I found it a little confusing to navigate.  On the
plus side, most of the screens are pretty easy to handle, and it's not hard
to get things up and running.
*** In my opinion Versaterm is oriented to the casual user.  I found it
easier to set it up and get it running because there was no learning
of a scripting language involved, and the interactive terminal emulator
allowed me to step through the process and determine what strings to wait
for etc.  In other words Versaterm is designed for NON-programmers.
On the other hand the connection scripts are VERY limited
and cannot handle more than about 4(or 5) steps.  This was Just enough
for me.

The configuration of MacSLIP is much more concentrated, and to my mind less
confusing.  However, you do have to write a connection script, which may be
daunting for some users.  The author tells me that he will be providing
some sample scripts which many users will be able to use more or less as
is.
*** also there is not facility to step through the process manually.
You can do it with BUY/NCSA Telnet 2.4.19 (and I think NCSA Telnet 2.5).

It should be noted that neither package requires you to use a script; you
can setup your SLIP connection with a terminal emulator, and then switch on
SLIP.  VersaTerm SLIP even includes a mini-emulator right in the VersaTerm
AdminSLIP application.  This is fine for casual use, but I'd recommend
getting a script going as soon as possible.

USE

As I said before, both packages work fine.  I have only 2400 baud MNP-5
modems, so performance for me wasn't great.  Here are some quick benchmarks,
done on my Q700, with Multitech 224E modem into a Cisco terminal server
(which does not do compressed SLIP):

                                  MacSLIP    VersaTerm SLIP
Fetch 45K MacBinaryII Upload:     161 cps    219 cps
Fetch 45K MacBinaryII Download:   308 cps    216 cps

PLEASE: these were all single runs; I'm not sure they mean much of
anything.  MacSLIP was using an MTU of 1500, whereas VersaTerm SLIP an MTU
of 1006 (the largest it allows).
*** Versaterm Slip now allows 1500 byte MTU sizes.  The poor performance
of Versaterm Slip download can be improved by setting the retransmit
timer to 0.  My experience (including line traces) indicates that Versaterm
Slip deleted acknowledges when the timer is non-zero.  I consider this a
bug but they author isn't interested in fixing this since a new version
of MacTcp should make this timer unneccessary.  On the other hand the
superior upload perforamance is probably due to this timer.  With
the timer set to zero, I find that downloads (and therfore most interactive
things MacX especially) are about 10-20% slower in MacSlip for reasons
I have not uncovered yet.

Both of these packages are a joy to use with Eudora. If you've ever had
trouble with corrupt attachments over modems, you want one of these.
*** Strongly agreed.  

Given the relative wimp factor of my modems, I find SLIP unacceptable for
interactive use (eg, NCSA Telnet).  However, at higher speeds they should
work just fine.
*** Given my 14,400 Baud SupraFax, I find interactive performance
relatively good.  I use compression, so the total round trip time
is quite high.  This means that character echo is about one second, but
typeahead works well, and screen redraws go quickly.  I use MacX with
SLIP and find the performance quite acceptable.  

CONCLUSIONS

Either package will serve you well.  VersaTerm SLIP is available now,
bundled with VersaTerm; if you need a terminal emulator and the other
goodies that come with VersaTerm, you could do much worse than to buy it.
*** I really like the FTP SERVER.  It is a CDev, and I leave it running
on my MAC at work.  Then I can FTP file directly from my home MAC to/from
my work MAC.

MacSLIP is not yet available; release is planned for the end of May. 
People with complicated dialins, or wishing to try multiple phone numbers
automatically, may prefer MacSLIP on that basis.  I'm also very fond of
MacSLIP's log, which has been helpful in tracking problems on our dialin
modems.
*** MacSlip is avialble.... see announcement later on...

PRICING

VersaTerm SLIP comes with VersaTerm 4.6.2, which goes for about $90
mail-order, and includes an FTP server and client, MacTCP, a Telnet
connection tool, and a time server and client.  Educational institutions
are eligible for a reduced price arrangement.
*** Many vendors only track the first two numbers IE 4.6 .  You may end
up buying 4.6.1 which does not have SLIP.  Just call then up and they
will send you an updated floppy, for no charge, via US Mail.  You should
allow an extra week for this though.

MacSLIP is $49.95.  Site licenses will be available for a reasonable price.
Contact macslip@utexas.edu for more information.
*** No longer true.  Send info requests to    info@hydepark.com .
Also see attached announcement.

DISCLAIMERS

I have no financial interest in either product.
*** Nor do I.

This review is not intended to be The Last Word on anything; it's just some
thoughts based on my limited experience with the two products.  More could
be said about either one.
*** Ditto.

SLIP is of limited utility unless you have something to SLIP with.  Before
you invest in SLIP, be sure your friendly neighborhood dialins support it.
-- 
Steve Dorner, U of Illinois Computing Services Office
Internet: s-dorner@uiuc.edu  UUCP: uunet!uiucuxc!uiuc.edu!s-dorner


*** Mark Isfeld    msi@nsd.3com.com