1. C2W Protocol Specification Group 1 Project RES 302

2. Introduction  Objectives  Working Environment  Characteristics  ACK and timeout system  CHECK System  Packet Formats  Typical Scenarios

3. Objectives  C2W Application  A protocol to coordinate the communication between the client and the server  A simple protocol and easy to implement  Security, Reliability, Compatibility

4. Working Environment  Application Layer  Working with unreliable transportation protocol (e.g UDP)  Possibility of connection failure/interruption/

5.  UID : User ID  Uniquely allocated with the connection ACK  RID : Room ID  0: main room;1-255: movie room  MID : Message ID  Unique between server and client for:  Chat message, User list, Movie list Characteristics

6. ACK and timeout system  Each information message is numbered  Return ACK after successful reception  Timeout and retry in case of message loss

7. CHECK System Every given time(Default: 1 min) Server Client Timeout and auto-disconnection Normal Scenario Check ACK Check Request

8. Packet Formats  2 message types Control MSG / Information MSG  4 packet formats Control Message ClientServer Information Message

9. Client Control Message

10. Server Control Message

11. Client Information Message

12. Server Information Message

13. Typical Scenarios  Connection and Disconnection

14. Typical Scenarios

16.  Chatting in main room and movie room  Displacement  Chatting privately with other user

19. Conclusion  Advantage  Security, Reliability, Certainty, Compatibility  Perspective  Possibility to encrypt the message content  Anticipation window

20. Thanks! Do you have any questions? Yifu Tang Tengfei Zhai Jiaying Huang Botu Sun