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![Page 1: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/1.jpg)
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How to Identifythe Speed Limiting Factor
of a TCP Flow
E2EMON 2006Vancouver
Mark TimmerApril 3, 2006
Co-authors: Pieter-Tjerk de Boer and Aiko Pras
![Page 2: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/2.jpg)
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How to Identify the Speed Limiting Factor of a TCP Flow
• Motivation• Related work• Possible factors• Overview: identifying the limiting factors• One factor in-depth• Measurement results• Conclusions
E2EMON, April 3, 2006
Contents
![Page 3: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/3.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Motivation
• Surfnet: 1 Gbit 10 Gbit
• Upgrades still useful?
• Approach: Identify speed limiting factor
![Page 4: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/4.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Related work
• Y. Zhang, L. Breslau, V. Paxson, and S. Shenker, “On the characteristics and origins of internet flow rates”,Proceedings of SIGCOMM’02
• M. Siekkinen, G. Urvoy-Keller, E.W. Biersack, and T. En-Najjary, “Root cause analysis for long-lived tcp connections”,Proceedings of CoNEXT’05
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Speed limiting factors of a TCP flow
TCPTCP(sender)
network(network layer, linklayer, physical layer) network
application application
(receiver)(sender)
(receiver)
layer
TCP
application
layer
![Page 6: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/6.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Overview: identifying the limiting factors
Data repository of packet traces
• Information directly available:– Arrival time– IP header (source, destination)– TCP header (port numbers, sequence number, acknowledgment
number, size of receive window)
• Information calculated:– Number of outstanding bytes– Achieved throughput
![Page 7: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/7.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Application layer limitations (1)
Slow sender limitation
Identification– Measure idle period percentage– Careful when receive window is empty
ack
A B
datadata
idle p
eriod
data
datadatadata
ack
Note:We only consider flows measured at the sending side
![Page 8: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/8.jpg)
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B
ack (rwnd=30)
ack (rwnd=30)
data (length=30)
ack (rwnd=0)
data (length=30)
A
E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Application layer limitations (2)
Slow receiver limitation
Identification– Measure how often the
receive window decreases
![Page 9: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/9.jpg)
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data (length=30)data (length=30)
ack (rwnd=150)
ack (length=0)ack (length=4)
ack (length=0)ack (length=4)
data (length=30)
data (length=30)data (length=30)
data (length=30)
A B
E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Application layer limitations (3)
Application protocol limitation
Identification– Measure how often an ACK
contains data
Note:We only consider flows sending data one-way
![Page 10: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/10.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Network limitation (1)
Limited by loss / retransmission
time
#outs
tandin
g byte
s ‘TCP Friendly formula’MSS cBWRTT p
![Page 11: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/11.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
– Large buffers– Entire receive window stored– Injecting more packets more delay
Network limitation (2)
Limited by delay
extra datathroughput of bottleneck link extra delay
![Page 12: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/12.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
TCP buffers limitations The receive buffer limitation The send buffer limitation
data (length=10data (length=10)
ack (rwnd=30)data (length=10)
ack (rwnd=30)ack (rwnd=30)
ack (rwnd=30)
data (length=10)ack (rwnd=30)
data (length=10)data (length=10)
data (length=10)
rwnd
full
rwnd
full
BA
60 by
tes
data (length=20)data (length=20)data (length=20)
ack (rwnd=100)A B
ack (rwnd=100)data (length=20)
data (length=20)data (length=20)
ack (rwnd=100)
ack (rwnd=100)
ack (rwnd=100)
60 by
tes
![Page 13: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/13.jpg)
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time1 t2 t4t3
receivewindow
#outs
tandin
g byte
s
t
E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
• Peaks
In-depth: the receive window limitation
data (length=10data (length=10)
ack (rwnd=30)data (length=10)
ack (rwnd=30)ack (rwnd=30)
ack (rwnd=30)
data (length=10)ack (rwnd=30)
data (length=10)data (length=10)
data (length=10)
rwnd
full
rwnd
full
BA
time1 t2 t4t3
receivewindow
#outs
tandin
g byte
s
t
![Page 14: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/14.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Measurement results
Category % flows % bytesUndetermined 20 – 40 10 – 20Network 20 – 30 30 – 40Send buffer 0 – 10 0 – 10Receive buffer 10 – 15 10 – 20Slow sender 20 – 30 20 – 40Slow receiver 0 – 5 0 – 5Application protocol 0 – 10 0 – 1
![Page 15: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/15.jpg)
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E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow
Conclusions
• Upgrading network still useful• However, many flows limited by buffers
• Recommentations:– Perform statistical analyses– Develop tool to ‘fix’ TCP-buffer limited flows– Detect changes of limiting factor in time
![Page 16: 1 How to Identify the Speed Limiting Factor of a TCP Flow E2EMON 2006 Vancouver Mark Timmer April 3, 2006 Co-authors: Pieter-Tjerk de Boer and Aiko Pras.](https://reader036.fdocuments.in/reader036/viewer/2022082510/5a4d1b527f8b9ab0599a7f71/html5/thumbnails/16.jpg)
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Questions?
E2EMON, April 3, 2006How to Identify the Speed Limiting Factor of a TCP Flow