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Basic foilset Session Management in Web Collaboratory Systems

Given by Tom Jurga at Defense of 5 CIS Master's Theses on Dec 15 1997. Foils prepared April 13 98
Outside Index Summary of Material

Session Management in TANGO System - about 30 minutes
  • Interleaved with the demonstration of TANGO capabilities
  • Basic architecture of Tango, Communication protocol
  • Detailed discussion of control application in Tango
Other Session Management mechanisms - about 10 minutes
Questions - 10 minutes

Table of Contents for full HTML of Session Management in Web Collaboratory Systems

 Denote Foils where Image Critical
Denote Foils where HTML is sufficient
1 Session Management in Web Collaboratory Systems
2 Presentation on Tango Client
3 Terms
4 TANGO System
5 TANGO System - Components
6 TANGO System - Components
7 TANGO System - Architecture
8 TANGO System - Technologies
9 TANGO System - Applications
10 TANGO System - Session Model
11 TANGO System - Session Model
12 TANGO System - Session model example
13 TANGO - Session Management mechanism
14 TANGO - Session Management actions
15 TANGO System - Communication Protocol
16 TANGO System - Communication Protocol
17 Control Application
18 Control Application - Architecture
19 Control Application - Functions
20 Control Application - Functions
21 Control Application - 1st version
22 Control Application - 1st version
23 Control Application - 2nd version
24 Control Application - 2nd version
25 Control Application - Customizability
26 Other Web Collaboratory Systems JCT
27 Other Web Collaboratory Systems NCSA Habanero
28 Other Web Collaboratory Systems Caltech Infospheres
29 Other Web Collaboratory Systems InVerse
30 Session Management - Summary
31 Session Model - Summary

Outside Index Summary of Material

HTML version of Basic Foils prepared April 13 98

Foil 1 Session Management in Web Collaboratory Systems

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Tomasz Jurga
NPAC
Syracuse University
Master Thesis
HTML version of Basic Foils prepared April 13 98

Foil 2 Presentation on Tango Client

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Session Management in TANGO System - about 30 minutes
  • Interleaved with the demonstration of TANGO capabilities
  • Basic architecture of Tango, Communication protocol
  • Detailed discussion of control application in Tango
Other Session Management mechanisms - about 10 minutes
Questions - 10 minutes
HTML version of Basic Foils prepared April 13 98

Foil 3 Terms

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Web Collaboratory System
  • Web infrastructure is pervasive and inexpensive
  • Web software is a truly open and extensible system
  • Web browser is rapidly becoming a socially acceptable human-computer interface
Session
  • Group of applications working together
Session Management
  • Set of actions that can be performed to change the state of a session, control the behavior of applications, or display information about session...
HTML version of Basic Foils prepared April 13 98

Foil 4 TANGO System

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
What is it?
  • Technically, it is a multiparty, multi-session, multiplatform, multimedia collaboratory system
  • It is also a software integration framework
  • It is fused with Web infrastructure
  • It provides dozens of multimedia collaboratory tools
  • It does not require any expensive infrastructure beyond a standard PC or Unix workstation and a browser
HTML version of Basic Foils prepared April 13 98

Foil 5 TANGO System - Components

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Local Daemons
  • maintain two-way communication between user applications, applets and the Central Server
  • launching local applications
  • implemented as a Plug-In in Netscape browser
Central Server
  • main communication element: routing of messages
  • maintains the system state data (participants, applications, sessions, etc.)
HTML version of Basic Foils prepared April 13 98

Foil 6 TANGO System - Components

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Local Applications
  • standalone programs written in any programming language
Java Applets
  • user applications written in the Java language
  • downloaded through the network from an HTTP server, and executed in a Netscape environment
Control Application
  • specialized Java applet which acts as the Session Management tool in TANGO and as the Graphical User Interface to the system
HTML version of Basic Foils prepared April 13 98

Foil 7 TANGO System - Architecture

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
HTML version of Basic Foils prepared April 13 98

Foil 8 TANGO System - Technologies

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Web Technologies used
  • Java - major system components are written in Java language
  • Plug-In Technology - to bypass Netscape security constraints, namely applet inability to open socket connection to anywhere. TANGO Plug-In overcomes this constraint, and enables communication with any Internet location
  • Netscape LiveConnect - communication between Java applets and TANGO Plug-In
HTML version of Basic Foils prepared April 13 98

Foil 9 TANGO System - Applications

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
TANGO system is arbitrarily extensible via set of APIs
  • Java applets
  • Java applications
  • JavaScript (collaborative web pages!)
  • C/C++
  • LISP (GNU software)
HTML version of Basic Foils prepared April 13 98

Foil 10 TANGO System - Session Model

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
A session is a group of application instances currently working together in a collaborative mode
All applications belonging to the same session exchange information and share behavior
How a particular application operates in the collaborative mode depends on the characteristics of this application type
HTML version of Basic Foils prepared April 13 98

Foil 11 TANGO System - Session Model

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
The modes of participation in a session:
  • the Master - has special privileges of controlling the application behavior and/or controlling access of other users to this session
  • the Slaves - all other participants
  • the Owner - the creator of the session
Master can be transferred to another participant
Ownership can not be transferred
HTML version of Basic Foils prepared April 13 98

Foil 12 TANGO System - Session model example

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
User A involved in two Chat sessions:
  • Sess 1: users C and D participate
  • Sess 2: user B participates
Master/slave logic:
  • transparent in case of Chat, namely application doesn't distinguish between master and slave
  • but TANGO still remembers who is M/S
Sess 1
Sess 2
A
B
C
D
HTML version of Basic Foils prepared April 13 98

Foil 13 TANGO - Session Management mechanism

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Displaying the accurate and consistent information about all established sessions on the Graphical User Interface panel on all machines
Generating a Session Management action, which may change the state of a session
7 Session Management actions in TANGO
HTML version of Basic Foils prepared April 13 98

Foil 14 TANGO - Session Management actions

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
"core" actions:
  • Creating a session
  • Joining an existing session
  • Launching an application remotely
  • Leaving a session
  • Closing an application remotely
"floor control" actions
  • Requesting the master mode
  • Granting the master mode
HTML version of Basic Foils prepared April 13 98

Foil 15 TANGO System - Communication Protocol

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Enables exchange of messages between the applications.
There is a following procedure of sending a message:
  • An application communicates with the Local Daemon by the use of method invocation and passes it the message that is to be sent
  • The Daemon encapsulates the message in a table of bytes and forwards it to the Central Server (TCP/IP connection)
HTML version of Basic Foils prepared April 13 98

Foil 16 TANGO System - Communication Protocol

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
The Central Server forwards the message to the addressee, i.e. to another Local Daemon, or to a group of Local Daemons
The communication protocol consists of several messages. They can be divided into two groups:
  • Application messages - exchanged among collaborating applications
  • Control messages - sent by Control Application after generating a Session Management action
HTML version of Basic Foils prepared April 13 98

Foil 17 Control Application

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Graphical User Interface to the TANGO system
Session Management tool providing the necessary functionality to control the behavior of other applications integrated with the system
Source of different information (e.g. user name, host name) for other TANGO applications
Place in TANGO
  • Java applet(s), runs under Netscape browser, downloaded from HTTP server to each client
  • communicates with the Server via Plug-In
HTML version of Basic Foils prepared April 13 98

Foil 18 Control Application - Architecture

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
HTML version of Basic Foils prepared April 13 98

Foil 19 Control Application - Functions

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Log in/out
Internal TANGO Mail
Session Management actions
  • create a session by launching an application locally
  • join an existing session
  • launch an application remotely
  • close a local application
  • close a remote application
  • become a master of a session
  • grant master mode to another TANGO user
HTML version of Basic Foils prepared April 13 98

Foil 20 Control Application - Functions

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Control Application displays the following lists:
  • TYPES - list of available TANGO application types
  • USERS - list of all users logged into the TANGO system, contains:
    • User name
    • Host name
  • SESSIONS - list of all sessions established in TANGO, contains:
    • Information about the type
    • The name of the master of a session
    • The other participants (slaves) names
HTML version of Basic Foils prepared April 13 98

Foil 21 Control Application - 1st version

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Several Java applets located on one Web page
Communication among applets by use of interfaces
The design influenced by:
  • time constraints
  • requirements from the funding agency
  • lack of programming experience in Java
HTML version of Basic Foils prepared April 13 98

Foil 22 Control Application - 1st version

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Very simple and unattractive graphical design
Unintuitive Session Management mechanism - generating any action requires 2 or 3 mouse clicks
No support and no guidance from Control Application for Session Management
Most new users totally confused when using this application
HTML version of Basic Foils prepared April 13 98

Foil 23 Control Application - 2nd version

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
More time for the design and implementation
Improvement goals:
  • Improvement in functionality - make it more intelligent so that it could guide a user when managing session
  • Improvement in the feel and look of the Graphical User Interface – make it visually attractive for potential users by:
    • making it more user-friendly
    • changing applications names (text) into graphical icons
    • adding visually attractive images into the background
HTML version of Basic Foils prepared April 13 98

Foil 24 Control Application - 2nd version

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Improved Session Management mechanism
  • buttons enabled when a session is selected. Their choice depends on the participation mode
  • Remote Close operation added
  • A window with the list of available users pops up for Remote Open, Remote Close, Grant Master operations
Improved GUI - Symantec package used
Full compatibility between the 1st and the 2nd versions of Control Application
HTML version of Basic Foils prepared April 13 98

Foil 25 Control Application - Customizability

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
TANGO - no flexible customizability mechanism
TANGOsim - example of how much effort was necessary to customize CA for 4 Command and Control Applications
TANGO 2 - fully customizable by:
  • Room paradigm
  • Applications customizability
  • Lock mechanism
HTML version of Basic Foils prepared April 13 98

Foil 26 Other Web Collaboratory Systems JCT

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
JCT - The Java Collaborator Toolset of Old Dominion University
AWT of the JDK is replaced by a custom collaboratory toolkit to provide event and data sharing
Advantage: simplicity of application porting.
Too restrictive approach: JCT is shared X written in Java
One session per application type allowed
HTML version of Basic Foils prepared April 13 98

Foil 27 Other Web Collaboratory Systems NCSA Habanero

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Habanero collaboratory modules are Java applications: no software downloadability, but independent from unstable Web browsers and their performance limitations
Habanero session model resembles TANGO 2 room paradigm:
  • defined as a meeting where any number of different types of applications can be opened
  • No automatic sending of update information about current sessions, however, it is done in case of information about participants
  • launching an application of a certain type within a session causes remote opening for all the participants in a session.
  • there is a floor control mechanism similar to the lock mechanism in TANGO 2 system.
  • save a session definition or state and to reconstruct it later.
HTML version of Basic Foils prepared April 13 98

Foil 28 Other Web Collaboratory Systems Caltech Infospheres

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
The system built with use of Java and supports peer-to-peer (no floor control) communication among processes spread across a network
Applications (dapplets) can exist without being linked to any session
Creating a session means establishing a temporary network of dapplets of any type
A dapplet can participate in many different sessions
Due to a loose integration between a dapplet and a session, this scheme of communication is very generic and flexible
HTML version of Basic Foils prepared April 13 98

Foil 29 Other Web Collaboratory Systems InVerse

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
The InVerse communications infrastructure receives data from applications and disseminates it over the network to the InVerse server and/or to appropriate destination client hosts.
Scalable infrastructure: may adapt itself to the available network bandwidth, observed network latency, availability of IP multicast routing, and installed security firewalls around user hosts.
A user can define a group of receivers (Individual, Private, Public etc) for a particular piece of data coming from his/her application.
Reliable or unreliable sending of data
Data Security - the system allows applications to establish secure communication sessions, data may be encrypted before sending
Session Management tools less powerful (no remote operations)
HTML version of Basic Foils prepared April 13 98

Foil 30 Session Management - Summary

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Session model:
  • multi/single type sessions
  • single/many sessions per application type
  • applications connected to one, many or none session
Session Management Actions:
  • Creating a session
  • Joining / Leaving a session
HTML version of Basic Foils prepared April 13 98

Foil 31 Session Model - Summary

From Session Management in Web Collaboratory Systems Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Opening / Closing of an application remotely
Floor Control mechanism
Sending the update information about the state of sessions to the users
Customizability of Session Management tools
Saving the state / the definition of a session
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