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TCP: Competitive with Extra Bandwidth and Time for Adjustment

This article explores how TCP (Transport Control Protocol) is competitive in scenarios with extra bandwidth and adjustment time. It discusses AIMD (Additive Increase, Multiplicative Decrease), email, web, and telnet, as well as file size, arrival time, and data flow. The text language is English.

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TCP: Competitive with Extra Bandwidth and Time for Adjustment

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  1. With Extra Bandwidth and Time for AdjustmentTCP is Competitive J. Edmonds, S. Datta, and P. Dymond

  2. TCP (Transport Control Protocol)AIMD (Additive Increase, Multiplicative Decrease) • Email • Web • Telnet

  3. File Size • Arrival time • Many Packets » Data Flow Input: Set of Sender/Jobs

  4. Adjustments B b b ,t ,t (not buffer or time delay) Bottleneck Capacity and Adjustments å£ B

  5. b ,t TCP (Transport Control Protocol)AIMD (Additive Increase, Multiplicative Decrease) A=1 c=½ Multiplicative decrease Additive increase Time

  6. Throughput & packet loss rate - arrival ) (completion AVG • “User Perceived Latency” or “Flow Time” Evaluating TCP • Good observed performance • Simulation of approximate models • Few theoretical results • [KKPS] 20 Questions to “guess” allocation • Fair to all Users • [CJ] Single-bottleneck:TCP fair • [F] Multi-bottleneck: TCP not fair

  7. a a c c , , … , , , , , , Bad(J) = … Good(J) = J = { … … } - a ) - a ) (c (c AVG AVG Bad(J) Good(J) User Perceived LatencyFlow Time n Long n » » = (n-1)e + Long

  8. TCP • [CJ] TCP ÞEQUI EQUI B B B Shortest Remaining Work First • Optimal Comparison with other Schedulers

  9. All Knowing All Powerful Optimal: ? Future Online: ? Non-Clairvoyant: TCP ? Distributed: Knowledge of Scheduler

  10. Not Competitive

  11. Competitive

  12. a EQUI(J) [MPT] £ 2 OPT(J) [ECBD] £ 3.73 Previous Results(Batch)

  13. a a a a a EQUI(J) [MPT] ³W(n) OPT(J) NonClair(J) ³W(n½) OPT(J) Previous Results(Lower Bounds)

  14. BAL1+e(J) [KP] £ O(1/e) OPT1(J) EQUI2+e(J) [E] £ O(1/e) OPT1(J) BROADCAST4+e(J) [EP] £ O(1/e) OPT1(J) Previous Results (Upper Bounds)

  15. £ O(1) Adj =å Adj Adj TCPO(1)(J) - Adj TCPO(1)(J) TCP(J) q q OPT(J) OPT1(J) OPT1(J) New Results

  16. EQUI2+e(J) [E] £ O(1) OPT1(J) Reduction Proof Sketch

  17. TCP • TCP ÞEQUI EQUI B B TCP Þ EQUI [CJ] global measure New: Job by job comparison

  18. b ,t Proof Sketch Unadjusted Adjusted

  19. b A=1 c=½ ,t Time Unadjusted Adjusted TCP³ (1-cq) EQUI b b ,t ,t at , After q , Proof Sketch

  20. TCPO(1) EQUI c=½ TCP TCP³ (1-cq) EQUI b b b b b b b ,t ,t ,t ,t at , After q , ,t ,t ,t TCPO(1)³EQUI Proof Sketch

  21. Proof Sketch EQUI

  22. Proof Sketch EQUI

  23. TCPO(1)(J) TCPO(1)(J) TCP(J) £ O(1) OPT(J) OPT1(J) OPT1(J) + Adj New Results

  24. TCPO(1) EQUI Less J’ £ TCPO(1)(J) EQUI2+e(J’) £ £ O(1) OPT1(J’) OPT1(J’ ) b b Adj OPT1(J) + + ,t ,t Proof Sketch J

  25. TCPO(1) EQUI Less J’ TCPO(1)(J) EQUI2+e(J’) £ £ O(1) OPT1(J’) OPT1(J’ ) b b Adj OPT1(J) + + ,t ,t ³ ³ Less = Proof Sketch J

  26. TCPO(1) EQUI Less Less Less Adj =å =å Adj Adj q q b b ,t ,t Less£ Adj Proof Sketch

  27. Less Adj q Less£ Adj Proof Sketch EQUI

  28. TCPO(1) EQUI Less J’ TCPO(1)(J) EQUI2+e(J’) £ £ O(1) OPT1(J’) OPT1(J’ ) b b Adj OPT1(J) + + ,t ,t ³ Less = Proof Sketch J

  29. TCPO(1) EQUI Less J’ TCPO(1)(J) EQUI2+e(J’) £ £ O(1) OPT1(J’) OPT1(J’ ) b b Adj OPT1(J) + + ,t ,t Proof Sketch J Done

  30. RecentResult Conclusion TCP is Competitive

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