IMDraw

1
IMDraw

• An Instant Message and Drawing Program
• Tim Poley
• Kelly Whitacre

2
Agenda

• Background
• IMDraw Design Decisions
• Client/Server vs. Peer to Peer Model
• TCP/IP vs. UDP
• Design Diagram
• Programming Hurdles
• Future Work
• Demonstration
• Questions

3
Background

• Early Instant Messaging- Talk
• Big Players Today
• AIM
• MS Messenger
• Jabber
• Trillian
• Why IMDraw?

4
Design Decisions Client/Server vs. Peer to Peer
Model

• P2P
• Advantages
• Performance Advantages with P2P Broadcasting
• File-Transfers
• Disadvantages
• Lower Performance with Heavy Loads

• Client/Server
• Advantages
• Server Manages Data
• Supports Off-line Messages
• Disadvantages
• Single Point of Failure

5
Design Decisions TCP/IP vs. UDP Message Protocol

• UDP
• Advantages
• Fast, Simple
• Low Delay (no transmissions)
• End-to-End Encryption
• Near Real Time transmission
• Disadvantages
• Possible out-of-order delivery of messages

• TCP
• Advantages
• Connection Disruption Detection
• More Reliable (retransmits when necessary)
• Detects Congestion in the Network
• Disadvantages
• Slower

6
Design Diagram
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Programming Hurdles

• Updating User Interface Controls Across Threads
• - C delegates/events used
• Server Crash after Client Logs Off
• - proper termination of threads used
• TCP Connection Terminates before it Sends Logout
  Message to Server

8
Future Work

• Secure Message Transfer
• UDP Message Protocol
• Multicasting
• User Defined Buddy Lists
• Add Additional Capabilities to Drawing Tool
• Streamline Messages

9
References

• http//en.wikipedia.org/wiki/Instant_messaging
• http//msdn.microsoft.com/library/default.asp?url
  /library/en-us/default.asp
• http//www.skullbox.net/tcpudp.php

10
Questions?
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Demonstration
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IMDraw Message Protocol-Supplemental

• IMDrawltSendergtltReceivergtltCommandgtltTextDetailsgt
  ltPoint1 xgtltPoint1 ygt....
• Command Login(0), Logout(3), Message(1),
  ClientList(2)

13
TCP-Supplemental