with extra bandwidth and time for adjustment tcp is competitive
DESCRIPTION
With Extra Bandwidth and Time for Adjustment TCP is Competitive. J . Edmonds, S . Datta, and P . Dymon d. TCP (Transport Control Protocol) AIMD (Additive Increase, Multiplicative Decrease). Email Web Telnet. File Size. Arrival time. Many Packets » Data Flow. - PowerPoint PPT PresentationTRANSCRIPT
With Extra Bandwidth and Time for Adjustment
TCP is Competitive
J. Edmonds, S. Datta, and P. Dymond
• Web
• Telnet
Bytes on the Internet
TCP
Other
TCP (Transport Control Protocol)AIMD (Additive Increase, Multiplicative Decrease)
•Arrival time
•File Size
Input: Set of Sender/Jobs
•Many Packets Data Flow
Adjustments
Bottleneck Capacity and Adjustments
B
b ,t
b ,t B
(not buffer or time delay)
Time
A=1 c=½
b ,t
Additive increase
Multiplicative decrease
TCP (Transport Control Protocol)AIMD (Additive Increase, Multiplicative Decrease)
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
User Perceived LatencyFlow Time
(c - a )AVG
J = { , , , , , , … , , }
Bad(J)Good(J) (c - a )AVG= n Long
(n-1) + Long n
Good(J) =
…… ca
Bad(J) =
… ca
Comparison with other Schedulers
BTCP
BEQUI
ShortestRemainingWork First
B
•[CJ] TCP EQUI
•Optimal
Knowledge of Scheduler
Non-Clairvoyant: ?
Online: ?Future
Distributed: ?
Optimal: All KnowingAll Powerful
TCP
Not Competitive
Competitive
Previous Results(Batch)
EQUI(J)OPT(J) 2[MPT]
[ECBD] 3.73
a
Previous Results(Lower Bounds)
EQUI(J)OPT(J) (n)[MPT]
NonClair(J)OPT(J) (n½)
aa aa a
Previous Results (Upper Bounds)
BAL1+(J)OPT1(J) O(1/)[KP]
[E] EQUI2+(J)OPT1(J) O(1/)
[EP] BROADCAST4+(J)OPT1(J) O(1/)
O(1)OPT(J)
TCP(J)
New Results
OPT1(J)TCPO(1)(J)
AdjAdj Adj
q q
OPT1(J)TCPO(1)(J) - Adj
Proof Sketch
[E] EQUI2+(J)OPT1(J) O(1)
Reduction
TCP EQUI
[CJ] global measure
BTCP
BEQUI
•TCP EQUI
New: Job by job comparison
Proof Sketch
b ,t
Unadjusted Adjusted
Proof Sketch
Time
A=1 c=½
UnadjustedAdjusted
b ,t
at ,
b ,t
After q ,TCP (1-cq) EQUI b ,t
Proof Sketch
c=½b ,tTCP
EQUI b ,t
at ,
b ,t
After q ,TCP (1-cq) EQUI b ,t
TCPO(1) b ,t
b ,tTCPO(1) EQUI b ,t
Proof Sketch
EQUI
Proof Sketch
EQUI
O(1)OPT(J)TCP(J)
New Results
OPT1(J)TCPO(1)(J)
OPT1(J) + AdjTCPO(1)(J)
Proof Sketch
O(1)OPT1(J)
TCPO(1)(J) EQUI2+(J’)OPT1(J’ )
Adj+ OPT1(J’ )+
J
TCPO(1) b ,t
EQUI b ,t
J’Less
Proof Sketch
O(1)OPT1(J)
TCPO(1)(J) EQUI2+(J’)OPT1(J’ )
Adj+ OPT1(J’ )+
J
TCPO(1) b ,t
EQUI b ,t
J’Less
Less
Proof SketchTCPO(1) b ,t
EQUI b ,t
AdjAdj Adj
q q
Less Adj
Less Less Less
Proof Sketch
EQUI
Less
Adjq
Less Adj
Proof Sketch
O(1)OPT1(J)
TCPO(1)(J) EQUI2+(J’)OPT1(J’ )
Adj+ OPT1(J’ )+
J
TCPO(1) b ,t
EQUI b ,t
J’Less
Less
Proof Sketch
O(1)OPT1(J)
TCPO(1)(J) EQUI2+(J’)OPT1(J’ )
Adj+ OPT1(J’ )+
J
TCPO(1) b ,t
EQUI b ,t
J’Less
Done
Conclusion
TCP is Competitive
Recent Result