CRIS System Documentation

______________________________________________________________________________

                       An Introduction to SLIP and TIA
______________________________________________________________________________



Table of Contents
=================

1.0  What Is This Document?
2.0  A Brief Explanation of the Internet
     2.1  A short history lesson
     2,2  Packet switching, protocols, and other strange stuff
     2.3  Did you ever wonder...
3.0  What is SLIP?
     3.1  A technical overview
     3.2  What does SLIP do for me?
     3.3  How do I use SLIP on my system?
4.0  What is TIA?
     4.1  Another technical overview
     4.2  What does TIA do for me?
     4.3  How do I use TIA on my system?
5.0  Using TIA on CRIS
     5.1  Where is TIA?
     5.2  Connecting to TIA from the Internet Area
     5.3  Connecting to TIA when you log in (faster)
     5.4  What do I do now?
     5.5  Disconnecting from TIA
6.0  Where Do I Go From Here?
     6.1  Finding software (e.g., Mosaic, FTP, Telnet, etc.)
     6.2  Getting help and ideas
7.0  Conclusion



                         1.0  What Is This Document?
______________________________________________________________________________

     This is a guide for users who want even stronger access to the Internet
than the Internet Area provides directly.  Normally, users call CRIS and enter
the Internet Area, and use it as a jumping-off point to explore the Internet.
With SLIP and TIA, you can use CRIS to connect your computer to the Internet
literally.  You will be able to run such programs as telnet, FTP, and most
excitingly, Mosaic, directly on your computer.

     This document explains what SLIP and TIA are.  It also describes how you
can use TIA in the Internet Area to establish a SLIP connection directly to
your machine.

     Lastly, it points you to the software you will need to use the SLIP/TIA
interface, and to instructions for downloading and installing that software on
your computer.



                  2.0  A Brief Explanation of the Internet
______________________________________________________________________________

     This section covers a brief history of the Internet, a dizzying
explanation of what "packet switching" is, and reveals why you can't just
"plug in" to the Internet.  At least, not until now.



2.1  A short history lesson
---------------------------

     During the 1960's, the United States Government began experimenting with
ways of connecting distant computers via telephone lines.  This project was
funded at first by the Department of Defense Advanced Research Projects Agency
(ARPA).  Originally, it connected only a handful of computers at governmnent
research sites.  The purpose was to provide ways of allowing researchers and
the military to communicate information quickly.

     This computer network employed a new idea in data communication.  The
Department of Defense was trying to find a system which could withstand a
nuclear attack by being able to reroute information in different ways if parts
of the network were destroyed.  The new idea, called "packet switching," is
still used today.

     Packet switching breaks outgoing data up into small pieces.  Each piece
is stamped with the name of its destination, much as a piece of mail is
addressed.  Then these pieces are sent onto the network.  The machines on the
network pass them from place to place until they reach their destination.
Then the packets are reassembled again.

     This is how the modern Internet works.  That original system designed by
ARPA rapidly began to be used for other purposes, such as electronic mail and
conferencing, and as more people became attached and saw new ways of using the
network, it grew.  The Department of Defense never foresaw the potential uses
of the Internet as it exists today, nor could they have predicted it given the
rapid changes in technology over the last thirty years.

     The original ARPA network contained at most a few hundred computers.  It
is currently estimated that as many as 25,000,000 people worldwide are
connected to the Internet in one form or another via more than 1,000,000
machines.



2.2  Packet switching, protocols, and other strange stuff
---------------------------------------------------------

     All communication between these people uses the packet switching
principle.  However, there are many different ways of breaking data up and
labelling the packets.  These different methods are called "protocols."  The
fundamental protocol for data communications on the Internet is the
Transmission Control Protocol or Internet Protocol, usually called "TCP/IP".

     There are also different ways to send and receive these data packets,
also called "protocols."  There are two important ones for connecting personal
computers to the Internet.  One is "PPP," the Point-to-Point Protocol, and the
other is "SLIP," the Serial Line Internet Protocol.

     Here's an analogy for what the protocols do.  Think of your data as a
long letter to Great Aunt Matilda, too long to fit into one envelope.  TCP/IP
tells you how to divide up your letter into different envelopes.  SLIP tells
you how to send and receive those envelopes once you're at the post office.
Once Aunt Matilda gets those envelopes, TCP/IP tells her how to put the letter
back together again.

     Great, you think.  So what?

     Almost all of this process is invisible to you, the user.  Billions of
packets of data are floating around on the Internet, and it's transparent to
you.   Programs like FTP, Telnet, and Mosaic, that operate on the Internet,
use a bewildering variety of protocols (FTP, HTTP, ICMP, SMTP, and so on) to
do the voodoo that they do.  Why should you care?



2.3  Did you ever wonder...
---------------------------

     The Internet is an enormous network of computers.  They are all
communicating to one another all the time, with a constantly-changing
configuration.  Why couldn't you just plug your computer in to the Internet
directly?

     Of course, with CRIS you do have access to the Internet.  You can log in,
go to the Internet Area, and from there you can use Telnet, FTP, Lynx, Pine,
and a whole host of other programs.  But why can't you just run them on your
own computer?  Why do you have to run them at CRIS at all?

     The reason is that, when you dial up with your modem, the kind of
connection you establish isn't capable of dealing with things like TCP/IP or
SLIP.  It's a plain, old-fashioned text connection.  If you want to be able to
use Internet features directly on your machine, it needs to be able to talk to
the machines at CRIS using a protocol like SLIP or PPP.

     Up until now, this has been a very difficult problem to solve.  Many IBMs
and Macintoshes are connected in various dedicated networks, and they are then
networked directly into the Internet.  So there are programs like Mosaic or
Telnet for your Macintosh or your IBM.  But those programs assume that your
machine is already hooked into the Internet.  And under normal circumstances,
the user with a modem can't plug in directly.

     Until now, that is.

     Now, CRIS can help you plug in directly, allowing you access to such
programs as Mosaic in all of its multimedia glory.  Or you can FTP files
directly to your machine.  Or you can read news, or Telnet...there's a very
long list of possibilities.

     With the appropriate software on your computer (software we make
available to you), you can connect to the Internet Area as usual.  Then with
TIA, you can convert that regular old, plain modem connection into a network
connection that uses SLIP.  And then, in a very real sense, your computer
becomes part of the Internet for as long as you're connected to CRIS.

     So much for the motivational material.  In the next sections we'll
describe how SLIP and TIA work, and the steps needed to use TIA with your
system.



                             3.0  What is SLIP?
______________________________________________________________________________

     This section briefly discusses what SLIP is, what it has to do with your
computer, and what is involved in getting it running on your system.


3.1  A technical overview
-------------------------

     As we described above, SLIP stands for "Serial Line Internet Protocol."
A protocol is just a set of rules for allowing machines to talk to one
another.  It is one of several protocols that are used to send information
across the Internet.

     The phrase "serial line" refers to the kind of communications line the
information is being sent along.  A serial line is one that only sends or
receives one bit of information at a time.  The most important kind of serial
line is a regular telephone connection.  (In contrast, parallel lines can send
or receive multiple bits at once.)

     A good analogy for a serial line is an old-style telegraph system, with
an operator at either end of the wire.  Each operator can tap out information
but only one can be sending at any time, and can only send one letter at a
time.  This is the kind of system that your telephone line uses.  SLIP was
designed to connect Internet machines across such serial lines.



3.2  What does SLIP do for me?
------------------------------

     Because there are a large number of Macintosh and IBM computers connected
to the Internet, there are a variety of Internet programs available for those
machines.  For example, there are versions of Mosaic for both the Macintosh
and the IBM.  Similarly, there are programs for FTP, Telnet, versions of Pine,
Elm, newsreaders, and the like.

     These programs actually do run on your computer.  They are not running on
some remote machine.  When you go to the Internet Area in CRIS and use Telnet,
say, you are running the Telnet program (that's all Telnet is, a program) on a
machine located at CRIS headquarters.

     In contrast, once you have established a SLIP connection to your
computer, you can run a program on your own machine to do the same thing.  So
instead of running Telnet in the Internet Area, you would run some kind of
Telnet program right on your Macintosh or IBM, just as you would run games,
word processors, or any other application.  Your machine does all the work --
it sends the data, receives it, and processes it.  All CRIS does is relay your
information to and from the Internet.

     The advantage of this approach is that you can, for example, FTP programs
directly down to your computer, instead of FTPing them to your CRIS account
and then downloading them from CRIS to your computer.  Or you can store your
mail on your own machine directly.

     With SLIP, you can also run several different Internet programs at once.
So, for example, you could Telnet in one window, have an FTP session
downloading files in a second, and run Mosaic in a third.  For users who want
to get the most out of the Internet, this is a fantastic advantage.

     Perhaps the most exciting advantage is that you can run Mosaic on your
computer.  Mosaic is the most popular browser of the World Wide Web.  It is a
multimedia program that displays graphics, plays sounds, shows movies, and
displays texts from across the Internet in a variety of fonts and colors.

     Normally, all CRIS users can run the Lynx program, which is also a World
Wide Web browser, but one that can only display text.  Mosaic offers you the
full range of Internet multimedia capabilities.

     As you can see, there are many advantages of using SLIP.  What are the
disadvantages?  None.  You can always choose to use the Internet Area just the
same way as you always did.  And whenever you want the power of a SLIP
connection, you have it immediately at your fingertips.



3.3  How do I use SLIP on my system?
------------------------------------

     Depending on whether you have a Macintosh or an IBM computer, there are
different basic SLIP packages available.  Of course, just having a program to
handle your SLIP connection isn't very exciting.  You will also want to
download programs for things like FTP, Telnet, or Mosaic.

     CRIS makes all of these packages available on its system.  In order to
find out which is the right software for you, and how to download, install,
and use that software, see the following guides:

     For Macintosh users, see "Using SLIP on the Macintosh."  For IBM users,
see "Using SLIP on the IBM."  These documents will explain just what you need
in order to make your system ready to take advantage of TIA on CRIS.  They go
step-by-step with you to install the software you'll need, and they also help
you install the Mosaic package, so you can begin to use the Internet quickly
and easily.  You can get them from the TIA forum on the Information Service,
and they are also available in the Internet Help System.



                              4.0  What is TIA?
______________________________________________________________________________

     This section explains what the TIA system is, and gives a brief
description of how it works.  It also details how to find out what you need on
your own computer to make TIA work for you.


4.1  Another technical overview
-------------------------------

     The CRIS Internet Area provides CRIS users with the ability to explore
and use the Internet.  However, it does this at second-hand.  You first log in
to CRIS, and then from the CRIS system you run Internet applications such as
Telnet or FTP.

     In the past, it has been difficult for most people to connect directly to
the Internet.  In order to interface directly with the Internet over a dial-in
telephone line, your system must be able to communicate with a serial line
protocol, such as SLIP or PPP.  Many of the applications designed for the
Macintosh or the IBM that use these protocols simply assume that you are
already connected to the network.  Very few programs exist to start up SLIP or
PPP connections.

     Even if you have the right programs, you still have to have access to a
remote system that will receive your SLIP or PPP packets and send them out to
the Internet, as well as sending packets back to your computer correctly. With
the TIA package, the CRIS Internet Area can do this for you very simply and
easily.

     "The Internet Adapter," or TIA, is a program designed to convert an
ordinary dial-in connection into a SLIP-like communications line.  In order to
use it, you dial CRIS normally.  Then you go to the Internet Area where the
TIA software is found.  Then, whenever you like, you can activate TIA, and
from then on you can run SLIP applications directly on your home computer.



4.2  What does TIA do for me?
-----------------------------

     The practical effect of using TIA is that you can now quickly and easily
run Internet application programs on your computer.  There is a wide variety
of software already developed for the Macintosh and the IBM to be used on the
Internet.  This software was designed to be used on computers that had direct
connections to the Internet.  Through CRIS and TIA, your computer now has that
ability.

     In particular, there are Macintosh and IBM (for the most part, Microsoft
Windows) applications for Telnet, FTP, newsgroup reading, electronic mail, and
the like.  Also, the extremely-popular multimedia program Mosaic is available
only via a SLIP or PPP connection.  With Mosaic, you can explore the Internet
with full-color graphics, animation, and sounds.

     In short, TIA allows you to run your favorite Internet applications
directly from your computer, instead of having to go to the CRIS system to run
them there.

     Also, with a SLIP connection instead of an ordinary dial-in connection,
your system can have multiple "sessions" running at once.  A "session" is a
particular activity on the Internet, such as Telnet, FTP, or Mosaic.  SLIP
supports having several programs all operating at the same time -- so you
could, for example, be in Telnet in one window, downloading a file with FTP in
another window, and running Mosaic in a third.  For heavy users of the
Internet, this feature alone makes TIA both worthwhile and an incredible
advantage over the old ways of accessing the Internet.



4.3  How do I use TIA on my system?
-----------------------------------

     We need to clarify a little here.  TIA is a program which operates on the
machines at CRIS headquarters.  What TIA does is to tell the CRIS machines to
send and receive communications with your computer using SLIP, rather than a
regular dial-in connection.  TIA is not a program on your computer. You do not
download TIA.  You only run it in the Internet Area, the same way you would
run Telnet, Lynx, Pine, or any other Internet Area program.

     In order to use TIA, however, you need to have SLIP software on your own
computer.  Once the CRIS machine is sending and receiving with SLIP, your
computer has to be able to transmit and receive also.  Ordinary communications
programs, such as Terminal, Procomm, or VersaTerm, do not understand SLIP.
You will need to use different software to manage your SLIP connection.

     This document does not get into the details of how to find SLIP software
for your system.  For information on SLIP software (CRIS provides you with a
variety of different packages and applications), see the documents "Using SLIP
on the Macintosh" and "Using SLIP on the IBM."  They are available in the TIA
forum in the CRIS Information System, and for Internet Area users, they can be
accessed through the Internet Help System.



                           5.0  Using TIA on CRIS
______________________________________________________________________________

     This section is the heart of this Introduction.  It explains how to get
to TIA, how to run it, and how to deactivate TIA when you are done using it.


5.1  Where is TIA?
------------------

     As described above, TIA is simply a program in the Internet Area, one of
many there.  There are two different ways you can access TIA on CRIS.  One is
by going to the Internet Area and running TIA there.  The other is directly
when you log into CRIS.

     In order to run TIA from the Internet Area, you must first go there. To
go to the Internet Area when you first log in to CRIS, choose option 3,
"Cybershuttle to Internet," from the first menu.  Then from the Internet menu,
choose option 5, "Enter the Internet Gateway".

     From anywhere in the Information System, you can also get there simply by
typing "/GO INET" and choosing option 5.

     When you take either of these routes, you will see a message like

Building Link... Connected.

Welcome, Doylep (Doylep@cris.com), to The CRIS Internet Area!
Last login: Wed Oct 19 16:18:01. Using host voyager.cris.com.

After you see the list of important notices, you will be placed at the
CRC Internet Area (INET) prompt:

CRCINET 1> _

     and from here you will be able to run TIA (or any other Internet Area
program, for that matter).

     If you want to run TIA from the login prompt, you simply indicate at
login time that you're only connecting to CRIS to use TIA.  Then CRIS will
activate TIA as soon as you've given your name and password.  Below, we
explain how to connect to TIA via either method.



5.2  Connecting to TIA from the Internet Area
---------------------------------------------

     In order to activate TIA, you first need to be at the prompt in the
Internet Area, which looks like this:

     CRCINET 1> _

     At the prompt, all you need to do to run TIA is type "tia".  Notice that
it must be in all lowercase letters.  Here's how it looks when you run TIA:

CRCINET 1> tia


The Internet Adapter (tm) 1.04 for SunOS
Copyright (c) 1994 Cyberspace Development, Inc.
Host License

Ready to start your SLIP software.

     Once you see this message, CRIS has switched over to sending/receiving
with your computer using SLIP.  At this point you will want to switch over
from your ordinary terminal program to whatever SLIP software you want to use.
See the "Using SLIP" guides for details on how to do this.



5.3  Connecting to TIA from login (faster)
------------------------------------------

     A much easier way to use TIA is to connect to it when you first log in to
CRIS.  This way, rather than being given any menu options, your SLIP
connection will be enabled as soon as you have verified your name and
password.

     To tell CRIS that you want to go directly to TIA, all you have to do is
add the word"slip" to the end of your name when you log in to the system.
Then CRIS will take you directly to TIA.

     Here's how it would look:

Enter your username or type 'new' if new user: doylep@slip
Password: ********

The Internet Adapter (tm) 1.03 for SunOS
Copyright (c) 1994 Cyberspace Development, Inc.
Host License

Ready to start your SLIP software.

     At this point CRIS is ready to handle your SLIP communications, and you
can begin running your SLIP software.  You don't need to enter the CRIS
menuing system at all.

     We recommend this approach, because it saves you the trouble of having to
go through the Internet Area to use TIA.  Also, you will find that your
connection is quicker, because CRIS doesn't have to send your data through the
Internet Area first; it can send it directly out to you.



5.4  What do I do now?
----------------------

     CRIS is now ready to communicate with you using SLIP.  Now you can run
whatever Internet applications you would like to use on your own machine, such
as Mosaic or FTP.  CRIS will maintain the SLIP connection until you
deliberately disconnect.

     IMPORTANT You must specifically deactivate TIA when you are done using
     it.  Otherwise, you will continue to be connected to CRIS, even if you
     have terminated all of your local Internet applications!

     Again, details on how to terminate your local SLIP connection and get
back into normal dial-up mode can be found in the "Using SLIP" guides.  They
are available in the Information System in the TIA forum, and they can be
accessed in the Internet Area from the Internet Help System.



5.5  Disconnecting from TIA
---------------------------

     All right.  At this point we assume that you have finished using whatever
Internet applications you wanted to run on your own computer.  Now you need to
deactivate TIA in order to get back to normal dial-in communications with
CRIS.

     In order to deactivate TIA, you need to send five Control-C characters
about a second apart to tell TIA that you are finished.  That is, you need to
hold down the Control key and press the C key five times in a row.  When you
do this, TIA terminates, and automatically disconnects you from the system.



                        6.0  Where Do I Go From Here?
______________________________________________________________________________

     This section gives you some pointers about where to turn for more
information, where to look for software packages, and how you can get help if
you are having problems.


6.1  Finding software (e.g., Mosaic, FTP, Telnet, etc.)
-------------------------------------------------------

     Knowing how to use TIA isn't useful unless you have application programs
to use it with.  CRIS keeps a large file archive of software for you to run
with SLIP and TIA.

     The documents "Using SLIP on the Macintosh" and "Using SLIP on the IBM"
are step-by-step guides to installing and using the software you'll need to
make your SLIP connection to CRIS.  They also cover installing some basic
Internet applications, to help get you started.  In addition to those, the
documents "Recommended SLIP Software for Your Macintosh" and "Recommended SLIP
Software for Your IBM" give detailed lists of all of the applications CRIS has
available for you and how you can access them.

     All of these documents are available on the Information System in the TIA
forum.  They are also all accessible in the Internet Help System in the
Internet Area.


 
6.2  Getting help and ideas
---------------------------

     As with all CRIS services, you can contact Customer Service either by
telephone, via e-mail, or on-line if you have questions about SLIP, TIA, or
how to install the software on your system.

     On-line help is available from 6 p.m. until midnight (EST) seven days a
week in Conference Eight on the Information System.  You can go directly to
this conference by typing "/GO HELP" or "/GO SERVICES" from anywhere in the
Information System area.

     In addition, you can call Customer Service, Monday through Friday, 9:30
a.m. until midnight (EST).  The telephone number is 1-800-745-CRIS.  You can
also send electronic mail with questions or comments to "custserv@cris.com" at
any time.

     To find out more about TIA, or to discuss TIA, SLIP, and the Internet
with other users, there is now a TIA forum on the Information System.  You can
"/GO TIA" from anywhere on the Information System to go directly to the TIA
forum.  It contains conversation, suggestions, and tips, as well as a file
library of documents and programs for using SLIP.

     On the Internet Area, you can find out more about SLIP and TIA by using
the Internet Help System.  Just type "ihelp" at the CRIS-INET prompt.  The
Help System will explain where to go for more information, including automatic
downloading of helpful documents.



                               7.0  Conclusion
______________________________________________________________________________

     This guide was intended to help explain what SLIP is, what the Internet
Adapter is, and how you can use them to connect your machine directly to the
Internet.  We hope that you are excited by the prospect of bringing programs
like FTP, Telnet, or Mosaic right to your computer.  With TIA, the process is
now fast, simple and easy.


     An Introduction to SLIP and TIA / CRIS / support@cris.com



