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Published byDerek Horn Modified over 9 years ago
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With Extra Bandwidth and Time for Adjustment TCP is Competitive J. Edmonds, S. Datta, and P. Dymond
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Email Web Telnet TCP (Transport Control Protocol) AIMD (Additive Increase, Multiplicative Decrease)
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Arrival time File Size Input: Set of Sender/Jobs Many Packets Data Flow
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Adjustments Bottleneck Capacity and Adjustments B b,t b,t B (not buffer or time delay)
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Time A=1 c= ½ b,t Additive increase Multiplicative decrease TCP (Transport Control Protocol) AIMD (Additive Increase, Multiplicative Decrease)
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Evaluating TCP Fair to all Users Good observed performance Simulation of approximate models Few theoretical results [KKPS] 20 Questions to “guess” allocation [CJ] Single-bottleneck:TCP fair [F] Multi-bottleneck: TCP not fair (completion - arrival ) AVG “User Perceived Latency” or “Flow Time” Throughput & packet loss rate
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User Perceived Latency Flow Time (c - a ) AVG J = {,,,,,, …,, } Bad(J) Good(J) (c - a ) AVG = n Long (n-1) + Long n Good(J) = … … c a Bad(J) = … c a
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Comparison with other Schedulers B TCP B EQUI Shortest Remaining Work First B [CJ] TCP EQUI Optimal
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Knowledge of Scheduler Non-Clairvoyant: ? Online: ? Future Distributed: ? Optimal: All Knowing All Powerful TCP
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Not Competitive
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Competitive
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Previous Results (Batch) EQUI(J) OPT(J) 2 [MPT] [ECBD] 3.73 a
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Previous Results (Lower Bounds) EQUI(J) OPT(J) (n) [MPT] NonClair(J) OPT(J) (n ½ ) aaaaa
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Previous Results (Upper Bounds) BAL 1+ (J) OPT 1 (J) O(1/ ) [KP] [E] EQUI 2+ (J) OPT 1 (J) O(1/ ) [EP] BROADCAST 4+ (J) OPT 1 (J) O(1/ )
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O(1) OPT(J) TCP(J) New Results OPT 1 (J) TCP O(1) (J) Adj qq OPT 1 (J) TCP O(1) (J) - Adj
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Proof Sketch [E] EQUI 2+ (J) OPT 1 (J) O(1) Reduction
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TCP EQUI [CJ] global measure B TCP B EQUI TCP EQUI New: Job by job comparison
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Proof Sketch b,t Unadjusted Adjusted
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Proof Sketch Time A=1 c= ½ Unadjusted Adjusted b,t at, b,t After q, TCP (1-c q ) EQUI b,t
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Proof Sketch c= ½ b,t TCP EQUI b,t at, b,t After q, TCP (1-c q ) EQUI b,t TCP O(1) b,t b TCP O(1) EQUI b,t
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Proof Sketch EQUI
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Proof Sketch EQUI
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O(1) OPT(J) TCP(J) New Results OPT 1 (J) TCP O(1) (J) OPT 1 (J) + Adj TCP O(1) (J)
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Proof Sketch O(1) OPT 1 (J) TCP O(1) (J) EQUI 2+ (J’) OPT 1 (J’ ) Adj + OPT 1 (J’ ) + J TCP O(1) b,t EQUI b,t J’ Less
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Proof Sketch O(1) OPT 1 (J) TCP O(1) (J) EQUI 2+ (J’) OPT 1 (J’ ) Adj + OPT 1 (J’ ) + J TCP O(1) b,t EQUI b,t J’ Less Less
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Proof Sketch TCP O(1) b,t EQUI b,t Adj qq Less Adj Less
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Proof Sketch EQUI Less Adj q Less Adj
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Proof Sketch O(1) OPT 1 (J) TCP O(1) (J) EQUI 2+ (J’) OPT 1 (J’ ) Adj + OPT 1 (J’ ) + J TCP O(1) b,t EQUI b,t J’ Less Less
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Proof Sketch O(1) OPT 1 (J) TCP O(1) (J) EQUI 2+ (J’) OPT 1 (J’ ) Adj + OPT 1 (J’ ) + J TCP O(1) b,t EQUI b,t J’ Less Done
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Conclusion TCP is Competitive Recent Result
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