Proposal of DIS Project Net Meeting System

Project Participants R 高茂原R 高茂原 R 饒訓豪R 饒訓豪 R 李建興R 李建興 R 莊美娟R 莊美娟

Motivation and Goals MotivationMotivation Goals:Goals: We will try to develop a net meeting system. Users at different physical locations can join the meeting via the net. They can discuss by sending messages, exchange screenshots, and drawing diagrams without the limitation of distances. We will try to develop a net meeting system. Users at different physical locations can join the meeting via the net. They can discuss by sending messages, exchange screenshots, and drawing diagrams without the limitation of distances.

Features 1.Chat room Send messages to other members Send messages to other members Receive messages from other members Receive messages from other members Save message records during or after the meeting Save message records during or after the meeting 2.Drawing pad Draw basic shapes or texts to illustrate ideas Draw basic shapes or texts to illustrate ideas 3.Screenshot transmission and display Transmit screeenshots to other members Transmit screeenshots to other members Save screenshots during or after the meeting Save screenshots during or after the meeting 4.Phone (optional)

Detail Descriptions Client-Server ModelClient-Server Model ServerServer 1.Serve as a user as well 2.Start up a meeting and wait for users to join in. When a user wants to participate the meeting group, the server can admit it by adding it to the group or refuse it.

Detail Descriptions (cont ’ d) ServerServer 3.When receiving notifications from users, it multicasts the change to other users. Message transmissionMessage transmission Screenshot transmissionScreenshot transmission Drawing actionDrawing action members leave the meetingmembers leave the meeting new user ’ s participationnew user ’ s participation 4.When it ’ s going to finish the meeting session, it multicasts end notification to members.

Detail Descriptions (cont ’ d) ClientClient –Send the participation request to a specific server in order to join a meeting –Send messages –Draw graphs –Transmit and display screenshots –Save logs during or after meeting MessagesMessages GraphsGraphs ScreenshotsScreenshots –Leave the meeting by sending a notification

Raionale and Justification Chat room: Total ordering: sequencerChat room: Total ordering: sequencer Drawing pad: FCFSDrawing pad: FCFS Screenshots: Members can fetch old screenshots by its id in the history listScreenshots: Members can fetch old screenshots by its id in the history list Election: When a server crashes, we use bully algorithm to select a new serverElection: When a server crashes, we use bully algorithm to select a new server

Failure Control The server will maintain the user list and detect member ’ s liveness periodicallyThe server will maintain the user list and detect member ’ s liveness periodically –Client crash: When a client crashes, the server will notice it and remove it from the user list. And then, notify other members to remove it as well. –Server crash: When the time a client does not receive detection messages from the server exceeds a limitation, or a client cannot send messages to the server, it holds an election to choose a new server by bully algorithm

Architechture Illustration

System Requirement and Implementation Development language: JavaDevelopment language: Java Middleware: RMIMiddleware: RMI Platforms: all platfroms that support javaPlatforms: all platfroms that support java

GUI Draft

Project Timeline

Job Distribution Architecture design: all membersArchitecture design: all members Interface design: all membersInterface design: all members ImplementationImplementation –Chat room: 莊美娟 –Whiteboard: 高茂原 –Image-transmission: 饒訓豪 –GUI: 李建興 –Phone: (optional) Debugging and testing: all membersDebugging and testing: all members Documentation: all membersDocumentation: all members