[2250] in Commercialization & Privatization of the Internet
SLIPing Questions and Answers
daemon@ATHENA.MIT.EDU (Brian Lloyd)
Sun Feb 2 23:42:23 1992
Date: Sun, 2 Feb 92 20:35:51 PST
From: brian@lloyd.com (Brian Lloyd)
To: bzs@world.std.com
Cc: vjs@rhyolite.wpd.sgi.com, com-priv@psi.com
In-Reply-To: Barry Shein's message of Sun, 2 Feb 92 13:29:03 -0500 <9202021829.AA17068@world.std.com>
Reply-To: brian@lloyd.com
Date: Sun, 2 Feb 92 13:29:03 -0500
From: bzs@world.std.com (Barry Shein)
Or do we now have 32 SLIP lines going into that classroom? And what's
the cost of *that*???
No more than that cost of 32 dumb dial-up lines and probably less
because you can run more than one person on one of those links. In my
experience you can run three or four telnet sessions over a single
V.32/V.42/V.42bis link without significant impact on the users. Now
the cost to 32 users drops precipitously because now you only need 8
modems and phone lines.
Performance of a SLIP or PPP link (I prefer PPP myself but I am
prejudiced) can be indistinguishable from a standard
character-at-a-time terminal if you use VJ header compression. Most
terminal servers now offer SLIP service and most will offer PPP
service. The use of PPP can automate the configuration process
because the "terminal" does not need to know its address ahead of
time. Therefore you have a relatively simple software package that
offers IP services over the link.
As for the impact on the terminal servers, my experience leads me to
believe that running SLIP on a link actually requires fewer system
resources than running a dumb terminal over the link. If you have a
dumb terminal you have to cook all the characters, process the TELNET
options, etc. Routing IP datagrams (especially at dial-up speeds) is
cake by comparison.
Now one last reason to run IP over the dial-up links: it's all the
same now. No longer do you have to deal with different kinds of
dial-up services; you have only one. And that service is very similar
to your other services (56K, T1, etc.). This CAN reduce your
administration costs.
So Barry, the terminal server approach is not necessarily the best.
Doing dial-up IP is not so hard and it is getting easier all the time.
It is certainly within the capabilities of most rational adult humans
to set up a properly designed dial-up IP link assuming that they are
given the necessary information in a complete and clear manner. Heck,
most people seem to think that PCs are easy. (Have you every mucked
about with TSRs and loadable drivers and other "user friendly" PC
programs?) Certainly configuring a one-user PC to talk SLIP or PPP is
no harder to deal with. Therefore, if the school or library has
trouble with that, they probably are unable to get their PC to do
anything anyway and IP/SLIP/PPP is the least of their problems.
Brian Lloyd, WB6RQN Lloyd & Associates
Principal and Network Architect 3420 Sudbury Road
brian@lloyd.com Cameron Park, CA 95682
voice (916) 676-1147 -or- (415) 725-1392
