<html>
<head>
<title>GAEN</title>
</head>
<body text="#FFFFFF" bgcolor="#000000"
link="#C0C0C0" vlink="#C0C000">
<hr>
<h1>GAEN - An Advanced Concurrent Teleconferencing System</h1>
<h2><a href="http://www.infoiasi.ro/~busaco">Sabin Corneliu Buraga</a></h2>
<p align=right>(<i>"Symposium on Automatic Control and Computer Science -
SACCS'98 Proceedings"</i> - November 1998, Iasi)</p>
<hr>
<h4>Abstract:</h4>
<ul>
GAEN is an advanced concurrent teleconferencing system which facilitate easy
and real-time communications between multiple persons. In fact, GAEN is a
network of talkers based on Internet TCP/IP protocols suite (implemented
with sockets). GAEN system is based on NUTS original program written by Neil
Robertson. After two years of experiments and work, it accumulates many
important and useful additions: GSL script internal language, a minimal shell,
response to events, support for natural talk: voice tones, socials and macros.
GAEN is implemented in standard C language under UNIX and it is distributed
freely on Internet. There are many operational GAEN talkers used by
students, researchers and other persons. In the present, GAEN systems are
running on Linux PC machines and they became very popular in
in the academical environments.
</ul>
<h4>Keywords: teleconference, concurrency, UNIX, event-driven talker,
Internet, scripts</h4>
<h2>General presentation</h2>
<p align=justify>
Like any other Internet services, GAEN uses the TCP/IP protocols, implemented
with BSD sockets. The most important GAEN services are:
<ul>
<li> <b>support for real-time and concurrent communications</b> between a variable
number of persons, with facilities like private messages, multiple
conferencing (private or public) rooms, an users ranks (levels) based system
<li><b> electronic mail</b>: sending and receiving of electronic messages (texts)
between the users and talkers via GAEN systems
<li><b> remote procedures calls</b>: an user can call commands which will be executed
on the GAEN host machine
<li> <b>GAEN network</b>: multiple GAEN systems can be interconnected respecting a
special protocol
</ul>
<p align=justify>
GAEN's philosophy is simple: in fact GAEN is a server (daemon) which provide
easy to use and powerful commands to facilitate the conversation between users
connected to talker via clients, like telnet programs.
GAEN needs three open ports: the main port and the auxiliary port (for the
administrators) are using to connect users to this teleconferencing service
and a netlink port is used
for connections between similar GAEN systems. GAEN provides its own
communication protocol used by interconnected talkers. This protocol is based
on a message passing interface (via netlink ports).
GAEN has conferencing rooms and dimensions (collections) of rooms and gives
to each user the possibility to execute a set of commands/actions such as
.say, .think, .tell, .whisper, .smail etc. to express common natural human
behaviour or to move to another room or dimension and so on (all commands
are prefixed by a period).
Of course, an user can talk to a particular person or a group of persons and
he/she can use customizable macros or a built-in set of macros and social
commands (e.g. shake hands, smiles, huggles, kisses etc.).
<h2>Connecting</h2>
<p align=justify>
The users have a free access, but after connecting they must use .set
to complete their personal information (real name, age, gender, e-mail address,
country).
<p align=justify>
Also, the users can enter a profile with additional information. To connect,
the users must use telnet and they must type the talker's address followed
by a port (e.g. telnet vela.uaic.ro 7000).
<p align=justify>
At the connecting time, the user must type a name and a password (each user
has an account, very similar with UNIX accounts). To avoid the
hackers attacks, we use a sophisticated and efficient system to deny insecure
(easy to guess and too simple) passwords. The users have the possibility to
change their own passwords. The talker's administrators can change other users'
passwords, too.
<p align=justify>
Following the society model, each user has a level (GUEST, SOUL, ...,
SPIRIT, SAINT, GOD). The number of levels is nine, but it can be modified.
For each level, there are some commands available to use. Of course, a higher
level offers more commands and posibilities than an inferior one.
<p align=justify>
In addition, each user has a short description, some status flags (colour,
muzzled, visibility, banned, ignoring other users and so on). Some flags and
other information (total login time, last login time, last connecting site)
are stored in files. For superior levels, an user has one or more clones
(to hear the conversation in multiple rooms).
<p align=justify>
Like in UNIX environments, there are commands to list all connected users
(.who and .people), their status and profiles (.status and .examine), their
remote host address etc. We written a command to get the real identity (the
account and the real name) of the user, if it's possible.
<p align=justify>
Also, the talker provides a robuste system to send and receive mail from
local or remote (from another linked talker) users. The users may have a
number of restrictions (concerning the execution of certain commands: to get
help, to review the room conversation, to be promoted or to create clones
etc.) and a number of run commands files (a sort of scripts) which contain
GAEN commands. These commands files can be executed by user (with .run) or
when an event occurs.
<h2>Rooms</h2>
<p align=justify>
Each room has a description, a short topic of conversation, the messages
board, a review buffer of the conversation, an access: public or private and
a state of visibility: hidden or not. Each room has links to another rooms
or to an external talker. The rooms' names and descriptions are loaded from
configuration files at the boot time. We don't need to recompile the sources
to modify the rooms links, dimensions or descriptions of rooms. We can
specify a default topic for each room (all of these information are stored in
text files and loaded at the booting time).
<h2>Administration</h2>
<p align=justify>
A GAEN system has one or more administrators ('superior' users of highest
level). Powerful commands assure the clever management of users: promotions
and demotions, the possibility to ban/unban sites and users or to delete users
using certain criteria, allowing users to use some facilities etc. Also, the
administrators can view and modify the internal parameters of the talker
using certain commands or changing the configuration files. The superior
users can consult the talker log files, too.
<h2>Original concepts and development</h2>
<p align=justify>
The list of all original and advanced implemented concepts is long.
We'll enumerate only the most important of them:
<ul>
<li><b> GSL (GAEN Simple Language)</b>
<ul><p align=justify>
GAEN includes a high-level scripting programming language which
offer run commands files executed by the logged on users, user private
variables, test (.if) and cycle (.for) statements. Using the flexible
.if command we can test the presence of an user, some status flags of an
user or talker's flags etc. It's possible to iterate the execution of a
command using .for and .execute commands.
</ul>
<li><b> gsh (GAEN SHell)</b>
<ul><p align=justify>
A minimal set of UNIX operating system commands is available: ls,
more, tail, grep, mkdir, cd, chmod, who, last, cp, mv etc.
</ul>
<li><b> events</b>
<ul><p align=justify>
Some actions of the users generate an event: log-in, log-out, shout,
broadcast of an important message and so on. For each event, the users are
able to associate a command to be executed when that event will occur.
</ul>
<li><b> user's environment</b>
<ul><p align=justify>
The possibility to save/restore some user information flags (such as
ignoring all tells flag, ignoring sending of pictures, the tone of the voice
etc.) in a special file.
</ul>
<li><b> internal hosts file</b>
<ul><p align=justify>
To avoid the waiting of response from name servers to obtain host
name of a connected user, we have the facility to consult an internal file
with IPs and host names (in the present, the hosts file counts more than 300
entries).
</ul>
<li><b> fun</b>
<ul>
<li>three interesting popular games: Hangman (two (Romanian and
English) dictionaries of more than 7000 words each), Puzzle and Paintball
<li>prayers, guessing, kill fun methods
<li>quotes
<li>greetings at pre/post login time
<li>ASCII pictures
<li>renaming users and substitution of true level/site
<li>blackhole simulation
</ul>
</ul>
<h2>Examples</h2>
<p align=justify>
Some examples of commands files using GSL and gsh facilities will
follow:
<oL>
<li>This script file is useful to delete all users without profiles:
<pre>
.set =} userfiles
.gsh scan } .if !entpro { : .delete {
</pre>
<p align=justify>
The .gsh scan command scans all entries of a directory (in this
case, the directory name is stored in a variable).
<li> A script to send mail only to users who are not playing Puzzle:
<pre>
.arun 0 .if !puzzle { : .smail { You don't like to play Puzzle?
.for 0 users
</pre>
<li> A backup utility script to save the user(s) files to another location:
<pre>
.arun 1 .note This script expects in { the user name
.arun 1 .set =} {
.arun 1 .note Copy in } variable because { is modified by .gsh scan
.arun 1 .gsh scan userfiles .run 2
.arun 2 .note Copy the filename stored in { into backup directory...
.arun 2 .note ...if filename contains the username stored in }
.arun 2 .gsh cd userfiles
.arun 2 .if in{ } : .gsh cp { ../backup
.arun 2 .gsh cd ..
</pre>
<p align=justify>
We can run the commands file 1 only to backup the files of Sabin,
Mituc and Beavis:
<pre>
.for 1 Sabin Mituc Beavis
</pre>
<p align=justify>
To backup files of all connected users we just are writing:
<pre>
.for 1 users
</pre>
<p align=justify>
To run the script only for an user:
<pre>
.set ={ Lumi
.run 1
</pre>
<li> Some actions automatically executed when an event occurs:
<pre>
.event shout .run 7
.arun 7 .social shake *
.arun 7 .tell * I'm happy, but it's not necessary to shout too much!
.arun 7 .macro cga
</pre>
<p align=justify>
The * variable contains the name of user who commit an event and
.macro cga means a colorful 'Congratulations!' message.
</ol>
<h2>Users and distribution </h2>
<p align=justify>
Without users, GAEN cannot exists. Since august 1996, we are
continuing to experiment with some versions of GAEN. In the present, the
GAEN teleconferencing systems are running on the sites of 'A.I.Cuza'
University of Iasi, at the Faculty of Computer Science (<tt>fenrir.infoiasi.ro
3300</tt>)
and the Faculty of Geography and Geology (<tt>vela.uaic.ro 7000</tt>) and the sites of
'G.Asachi' Technical University of Iasi, at the Faculty of Automatic Control
and Computer Science (<tt>hal.cs.tuiasi.ro 7777</tt>) and the Faculty of
Electronics
and Telecommunications (<tt>zeta.etc.tuiasi.ro 7000</tt>). The enumerated
talkers
build the GAEN system network, very popular among students and professors.
<p align=justify>
The researchers of the Institute for Information Science - Iasi
branch are using a version of GAEN system, too (on <tt>iit.iit.tuiasi.ro
7000</tt>).
<p align=justify>
We do not have a strict control of number of installed GAEN systems
because the sources and the additional files are distributed freely on
Internet at this Web address:
<a
href="http://www.infoiasi.ro/~busaco/gaen/">http://www.infoiasi.ro/~busaco/gaen/</a>.
GAEN distribution package includes the
source files (more than 15000 lines of code) written in standard C for UNIX systems
(to compile them we are using the GNU C compilers), configuration, additional
(quotes, pictures etc.) and help files. The OS/2 version of GAEN is available
on request.
<p align=justify>
There are more than 700 frequent 15-50 aged users from Romania
(Iasi, Bucuresti, Craiova, Brasov, Cluj, Bacau, Galati, Suceava), United
States of America, Great Britain, Finland, Denmark, Moldova Republic,
Israel etc.
<p align=justify>
The current version of the teleconferencing system is GAEN Goya 12,
which includes the changed logs files notify facility. In the future, we
intend to develop an AI support tool to extract the conclusions from the
conversation lines based on some predefined keywords.
<h2>Slides</h2>
<ul>
<li><a href="slide1.html">Slide 1 - GAEN's services</a>
<li><a href="slide2.html">Slide 2 - Original concepts and development</a>
<li><a href="slide3.html">Slide 3 - Examples of GSL scripts using gsh
facilities</a>
<li><a href="slide4.html">Slide 4 - Capture of a OS/2 telnet session of GAEN</a>
</ul>
<h2>REFERENCES</h2>
<p align=justify>
[1] W.Richard Stevens, Advanced Programming in the UNIX Environments,
Addison-Wesley, 1992
<p align=justify>
[2] Marc J.Rochkind, Advanced UNIX Programming, Prentice-Hall, New Jersey,
1985
<p align=justify>
[3] K.Blakeslee, I.Sugarbread, The Evolution of Personal Computing and
Communication, IFIP, 1994
<p align=justify>
[4] Andrew S.Tanenbaum, Retele de calculatoare, Computer Press Agora,
Tg.Mures, 1997
<p align=justify>
[5] Charles L.Hedrick, Introduction to the Internet Protocols, CSFG, Rutgers
University, 1987
<p align=justify>
[6] Jean-Marie Rifflet, UNIX - 99 exercices corigees, Ediscience, Paris,
1996
<p>
<hr>
</body>
</html>
