Better-Behaved Multimedia Networking Keith Barber Jason Ingalsbe Joel Thibault Prof. Mark Claypool (Advisor) April 19, 2001

Issues with Multimedia Traffic Basic Internet protocols inappropriate for multimedia –TCP does not provide smooth transmission –UDP takes up too much bandwidth Multimedia protocols must be TCP-friendly

Existing Alternatives TCP-Friendly Rate Control (TFRC) TCP Emulation At Receivers (TEAR) MM-Flow

Re-Engineering MM-Flow Location of flow control logic –“True” application and transport layers –Receiver decides whether scale value should change –Sender converts scale values to transmission rate Number of scale values Weighted average scale

Evaluation Techniques Simulation Scenarios –Standard Bottleneck Layout –Standard Delay Layout –Standard Fragile Layout

Standard Bottleneck Layout

Standard Delay Layout

Standard Fragile Layout

Effects of Re-Engineering MM-Flow Responsiveness to Congestion Fair Share of Bandwidth Relative Smoothness

MM-App-Old vs. TCP

MM-App-New vs. TCP

Further Evaluation of MM-App-New Packet Size Number of Scale Values Delay Fragile Flows Weighted Scale Values

TCP-Friendly Flows Possible definitions: –Flow uses fair share of bandwidth –Flow responds to congestion –Flow transmission rate less than or equal to TCP flow transmission rate Quantitative measurement is desired

TCP-Friendly Equation Implications and Assumptions: –Packet Drop Rate –Measurement Interval Size

TCP-Friendly Results (1 sec.)

TCP-Friendly Results (3 sec.)

TCP-Friendliness of MM-App-New

TCP-Friendliness of TFRC

Multi-Protocol Layout

Multi-Protocol Env. (TCP)

Multi-Protocol Env. (TFRC)

Multi-Protocol Env. (MM-App-New)

Conclusion and Future Work MM-Flow is an improvement over original Areas for future research: –Increase transmission rate quickly at startup –Decrease fluctuation in transmission rate –Continue examination of TCP-Friendliness

Questions?