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Basic foilset Message Routing and State Management in Collaborative Environments

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

Introduction
Collaboration Models
Collaboration Architectures
Tango2 System
Tango2 Server
Conclusions

Table of Contents for full HTML of Message Routing and State Management in Collaborative Environments

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1 Message Routing and State Management in Collaborative Environments
2 Content
3 Introduction
4 Introduction
5 Introduction
6 Collaboration Models
7 Asynchronous Collaboration
8 Synchronous Collaboration
9 Other Collaboration Models
10 Collaboration Architectures
11 Centralized Architecture
12 Server Network Architecture
13 Fully Distributed Architecture
14 Other Solutions
15 Tango2 - Overview
16 Tango2 - Architecture
17 Tango2 - State Management
18 Tango2 - State Management
19 Tango2 - Message Distribution
20 Tango2 Server
21 Tango2 Server - Architecture
22 Tango2 Server - Architecture
23 Tango2 Server - Message Flow
24 Tango2 Server - Message Flow
25 Conclusions
26 Conclusions

Outside Index Summary of Material

HTML version of Basic Foils prepared April 13 98

Foil 1 Message Routing and State Management in Collaborative Environments

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Lukasz Beca
NPAC
Syracuse University
HTML version of Basic Foils prepared April 13 98

Foil 2 Content

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Introduction
Collaboration Models
Collaboration Architectures
Tango2 System
Tango2 Server
Conclusions
HTML version of Basic Foils prepared April 13 98

Foil 3 Introduction

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Internet - basis for construction of the collaborative environments
Applications of the collaborative systems:
  • group work
  • distant learning
  • scientific collaboration
  • videoconferencing
HTML version of Basic Foils prepared April 13 98

Foil 4 Introduction

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Message routing
  • definition of the communication channels in the system
  • description of data transferred using the communication channels
    • control data
    • application data
HTML version of Basic Foils prepared April 13 98

Foil 5 Introduction

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
State management
  • maintaining and modification of the data essential for the proper operation of the system
  • state components
    • state of the collaboration framework
    • shared content state
    • application shared state
  • state update distribution
HTML version of Basic Foils prepared April 13 98

Foil 6 Collaboration Models

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Asynchronous collaboration
  • exchange of information without simultaneous contact with the system
  • collaborative session without defined time boundaries
  • one-to-many and one-to-one patterns
Synchronous collaboration
  • simultaneous presence of the users required
  • collaboration session time boundaries well defined
  • collaborative awareness
Other models
HTML version of Basic Foils prepared April 13 98

Foil 7 Asynchronous Collaboration

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Persistency of the state
Adding new data instead of modification
State update: polling and notification
Reliability of the communication channels
No strict time requirements for message delivery
HTML version of Basic Foils prepared April 13 98

Foil 8 Synchronous Collaboration

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Dynamic state
Different models of collaborative sessions
State distribution
  • synchronization
  • consistency
Shared state - mean of communication between applications
State changes distribution - notification
Time constraints imposed on the message delivery
Different requirements for communication channels parameters
  • quality of service
  • communication modes
HTML version of Basic Foils prepared April 13 98

Foil 9 Other Collaboration Models

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Combined functions of the synchronous and asynchronous systems
Session recording
Synchronous collaboration on the shared content
Application state saving
HTML version of Basic Foils prepared April 13 98

Foil 10 Collaboration Architectures

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Centralized
  • client-server
  • all clients connected to the central server
Server Networks
  • set of interconnected servers
  • members of the community served by local server
Fully Distributed
  • peer-to-peer
Other Solutions
HTML version of Basic Foils prepared April 13 98

Foil 11 Centralized Architecture

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
State stored in one place
Synchronization and consistency easily maintained
Shared objects and shared content
Clients connected directly to the server
Messages routed by the central server
Scalability problems
HTML version of Basic Foils prepared April 13 98

Foil 12 Server Network Architecture

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Changes of the state may occur on different servers
System state distribution
  • spanning tree configuration
  • flooding
  • server-server communication protocol
Patterns of communication
  • client-server-client
  • client-net of servers-client
Message route determination
HTML version of Basic Foils prepared April 13 98

Foil 13 Fully Distributed Architecture

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Distributed state
Problems with maintaining state consistency
Limited collaboration functionality
Session establishment
Multicast services
Best scalability
Smallest delay in message distribution
HTML version of Basic Foils prepared April 13 98

Foil 14 Other Solutions

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Hybrid solutions e.g. combining client-server and peer-to-peer architectures
  • client-server model for control and reliable application communication
  • peer-to-peer model for real-time application data distribution
Application content provided by HTTP servers
HTML version of Basic Foils prepared April 13 98

Foil 15 Tango2 - Overview

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Framework for building collaborative environments using WWW technologies
Functionality
  • support for communities and rooms
  • session management
  • event passing
  • shared variables and locks
  • session logging
  • system administration
  • access control
  • failure detection
HTML version of Basic Foils prepared April 13 98

Foil 16 Tango2 - Architecture

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
HTML version of Basic Foils prepared April 13 98

Foil 17 Tango2 - State Management

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
System state components
  • Server
    • Application settings
    • Rooms
      • Sessions
      • Users
      • Applications
      • Shared Locks
      • Shared Variables
      • Operations
    • Demon
      • Copy of the room state
HTML version of Basic Foils prepared April 13 98

Foil 18 Tango2 - State Management

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
State Modification
  • User Actions
    • room level actions
    • session level actions
  • Application Actions
  • Server Actions
  • Administrator Actions
  • Failure Detection
HTML version of Basic Foils prepared April 13 98

Foil 19 Tango2 - Message Distribution

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Types of messages
  • control messages
  • application event messages
  • application shared state messages
Channels of communication
  • server broadcast
  • room broadcast
  • session broadcast
  • unicast
HTML version of Basic Foils prepared April 13 98

Foil 20 Tango2 Server

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
One of the main elements of the Tango2 system
Provides services for several rooms
Functions
  • session management
  • event passing
  • shared variables and locks
  • communication channels
  • failure detection
Controlled by the administration interface
HTML version of Basic Foils prepared April 13 98

Foil 21 Tango2 Server - Architecture

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
HTML version of Basic Foils prepared April 13 98

Foil 22 Tango2 Server - Architecture

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
HTML version of Basic Foils prepared April 13 98

Foil 23 Tango2 Server - Message Flow

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Incoming messages
HTML version of Basic Foils prepared April 13 98

Foil 24 Tango2 Server - Message Flow

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Outgoing messages
HTML version of Basic Foils prepared April 13 98

Foil 25 Conclusions

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
The requirements imposed on state management and message routing depend on:
  • collaboration model
  • collaboration architecture
The most flexible solution:
  • centralized collaboration framework management
  • distributed application data delivery
HTML version of Basic Foils prepared April 13 98

Foil 26 Conclusions

From Message Routing and State Management in Collaborative Environments Defense of 5 CIS Master's Theses -- Dec 15 1997. *
Full HTML Index
Tango2 system
  • enables construction of the customized collaborative environments
  • collaborative applications have access to several types of communication and synchronization mechanisms
  • synchronous and asynchronous collaboration is supported
  • state management and reliable communication handled by the Tango2 server
  • content provided by the HTTP servers
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