C2W Protocol Specification Group 1 Project RES 302

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

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

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

 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

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

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

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

Client Control Message

Server Control Message

Client Information Message

Server Information Message

Typical Scenarios  Connection and Disconnection

Typical Scenarios

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

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

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