1. Performance Evaluation of PISA and PI using NS simulations Presented by Brad Burres Yatin Manjrekar

2. Agenda Introduction Background Setup Results Conclusion

3. Introduction 80% of traffic flows are short (http) and represent 20% of data 20% of traffic flows are long and represent 80% of data Prioritizing short flow transmission (dropping Long flows first) will help the network congestion Our scope is limited to TCP.

4. TCP Congestion control

5. AQM congestion control Droptail – FIFO RED – Random Early Detection SHRED- Short lived flow friendly RED DCN-Differential Congestion Notification PI – Proportional Integrator

6. DCN Flow Chart

7. PI algorithm

8. PISA Algorithm PISA – Proportional Integrator with Short-lived flow Adjustment It clamps queue length to Qref CWND hint in Type of Service field Drop probability is increased or decreased depending on cwnd ratio

9. PISA Algorithm cont.

10. PISA Algorithm Cont Weighted Cwnd Average

11. NS SETUP

12. Simulation setup

13. Simulations and Measurements Measurements Made –Queue Length Instantaneous Average –Drop Rate –Web Objects Transmission Time Items Transmitted –Utilization (pending) # FTP Sources # HTTP Sources HTTP Pareto Distribution 101001.2 501001.2 100 1.2 1001501.2 101001.3 501001.3 100 1.3 1001501.3

14. Queue Length (all graphs are the ftp 100, http 100, pareto = 1.3) PI AVG = 199.94 PISA AVG = 198.97 (both clamp to 200)

15. Packets Dropped (ftp10,http100,1.3 VS. ftp100,http100,1.3)

16. Web Object Transmission PI –Started 28630 –Finished 28549 PISA – Started 34358 –Finished 34273 For both, tails go out to 500 seconds

17. Conclusions PISA does a better job at giving priority to short flows There is still room for improvement We still need to do more analysis of the data

18. References [UW] Stefan Saroiu, Krishna Gummadi, Richard Dunn, Steven Gribble, Henry Levy, “An Analysis of Internet Content Delivery Systems”. [FJ93] S Floyd and V Jacobson, “Random Early Detection Gateways for Congestion avoidance”. IEEE/ACM Tractions on Networking [CJO01] M Christiansen,K Jeffay, D. Ott and F.D.Smith, “Tuning RED for Web Traffic” IEEE/ACM Transactions on Networking. [HCK02] M Hartling, M Claypool and R. Kinicki, “Active Queue Management for Web Traffic” Technical Report WPI-CS-TR-02-20, Worcester Polytechnic Institute, May 2002 [LAJS04] Long Le, Jay Aikat, Kevin Jeffay, F. Donelsom Smith “Differential Congestion Notification:Taming the elephant” IEEE/ICNP 04

19. References Cont. [K04]Minchong Kim, “Proportional Integrator with Short-lived flow adjustment” http://www.wpi.edu/Pubs/ETD/Available/etd-0122104- 154529/unrestricted/mjkim.pdfhttp://www.wpi.edu/Pubs/ETD/Available/etd-0122104- 154529/unrestricted/mjkim.pdf Thesis submitted to WPI Faculty, Jan 2004 [S04] David Sonderling. “Master Qualifying Project”. MQP submitted to WPI Faculty. 2004. [NS201]NS-2 Network Simulator http://www.isi.edu.nsnam/ns, September 2001http://www.isi.edu.nsnam/ns Jae Chung and Mark Claypool “NS by example” http://nile.wpi.edu/NS/ http://nile.wpi.edu/NS/ http://www.freesoft.org/CIE/Course/Section3/7.htm

20. Q & A ?? Comments