1. DCP: The Datagram Control Protocol Eiman Zolfaghari E190 – Technical Communications Professor Hatton April 2002

2. The Problem Audio streaming applications: Internet Radio is choppy. Video streaming applications: video is not smooth. Games: have long delay times. Why? Because most applications use a protocol in which all packets need to be accounted for.

3. Background Protocol - the way two computers communicate with each other. Transport Protocol - the protocol which defines how packets of data are sent from one computer to another TCP - Transmission control Protocol –Guarantees that all packets will get to its destination in order, and makes sure not to congest the network UDP - User Datagram Protocol –Guarantees nothing. Does not protect from congesting the network. Its all up to the application.

4. Current Solutions Leave it up to the application to decide when to send and receive packets –Make use of the simpler transport protocol, UDP Use other transport protocols currently being developed, such as SCTP.

5. Problems With Current Solutions ‘Re-inventing the wheel’: All applications will have the same algorithm on how they send packets. No control. What if someone writes a malicious application that sends out all the packets it wants? Other current transport protocols make packet sizes unnecessarily big.

6. A New Solution : DCP Usability: Applications don’t need to write an algorithm for how packets are sent. Protection: Makes sure that packets are sent at a fair rate. Efficiency: Small packet size.

7. How it Works Congestion Control Mechanism: Each node gets to choose how it wants packets to be sent and received so as to not cause congestion. Computer A initiates connection with computer B. –Exchange of information regarding congestion control mechanism to use Half-connection idea: Each node could have a different congestion control mechanism. Request Response Data[Ack] Close Reset Data[Ack] Initial feature negotiation

8. How it Works Request Response Data[Ack] Close Reset Data[Ack] Initial feature negotiation

9. Current Progress & Future Work Design is complete The IETF has approved it Still being implemented Testing being done To install it within operating systems such as Windows XP & Linux so application developers can use it Show test results Future Work:

10. In Conclusion Current Internet transport protocols available to and used by streaming media applications are problematic and sometimes don’t even work. DCP is attempting to solve the problem and allow all applications to use a universal way of streaming data without being unfair.