delay-based tcp congestion control - universitetet i...
TRANSCRIPT
![Page 1: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/1.jpg)
Delay-Based TCPCongestion Control
David Hayes
Centre for Advanced Internet Architectures (CAIA)Swinburne University of Technology
![Page 2: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/2.jpg)
Outline
CAIABackground
TCP congestion controlDelay based congestion signalsSome key delay-based algorithms
LCN paper Improved coexistence and loss tolerance fordelay based TCP congestion control
Hamilton Institute’s Delay-based algorithm (HD)Shortcomings of HD,improved by CAIA HD algorithm (CHD)
back-off decision frequency and scalingtolerance to non-congestion related lossimprovements when coexisting with NewReno type flows
Other TCP workDelay-gradient based congestion controlStateless TCP
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 2
![Page 3: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/3.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBD
CAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networksCovert channels and lawful interceptionNetwork monitoring and visualisationBGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 4: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/4.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)
Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networksCovert channels and lawful interceptionNetwork monitoring and visualisationBGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 5: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/5.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networksCovert channels and lawful interceptionNetwork monitoring and visualisationBGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 6: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/6.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)
Traffic classificationWireless networksCovert channels and lawful interceptionNetwork monitoring and visualisationBGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 7: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/7.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classification
Wireless networksCovert channels and lawful interceptionNetwork monitoring and visualisationBGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 8: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/8.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networks
Covert channels and lawful interceptionNetwork monitoring and visualisationBGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 9: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/9.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networksCovert channels and lawful interception
Network monitoring and visualisationBGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 10: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/10.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networksCovert channels and lawful interceptionNetwork monitoring and visualisation
BGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 11: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/11.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networksCovert channels and lawful interceptionNetwork monitoring and visualisationBGP
Address space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 12: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/12.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networksCovert channels and lawful interceptionNetwork monitoring and visualisationBGPAddress space exploration
Game traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 13: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/13.jpg)
CAIA –Centre for Advanced Internet Architectures
We are at Swinburne University of Technology, about 5 kmeast of the Melbourne CBDCAIA is the research arm of the TelecommunicationsEngineering Academic Group (or Department)Research spans:
Congestion control (TCP, etc)Traffic classificationWireless networksCovert channels and lawful interceptionNetwork monitoring and visualisationBGPAddress space explorationGame traffic analysis
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 3
![Page 14: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/14.jpg)
CISCO supported work
Exploring the efficacy of distributed statistical trafficclassification using modified open source packet filters(2010)
Implementing and testing delay-based and rate-basedtransport protocols in FreeBSD (2008)Heuristics to reduce BGP Update Noise (2007)FreeBSD Implementation of an SCTP friendly NAT (2007)Anomalous Traffic Detection and Collaborative NetworkConfiguration Using 3D Multiplayer Game Engines (2006)Public Implementation and Interoperability Testing of NextGeneration TCP Stack Under FreeBSD (2005)Dynamic Self-Learning Traffic Classification Based on FlowCharacteristics (2004)
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 4
![Page 15: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/15.jpg)
CISCO supported work
Exploring the efficacy of distributed statistical trafficclassification using modified open source packet filters(2010)Implementing and testing delay-based and rate-basedtransport protocols in FreeBSD (2008)
Heuristics to reduce BGP Update Noise (2007)FreeBSD Implementation of an SCTP friendly NAT (2007)Anomalous Traffic Detection and Collaborative NetworkConfiguration Using 3D Multiplayer Game Engines (2006)Public Implementation and Interoperability Testing of NextGeneration TCP Stack Under FreeBSD (2005)Dynamic Self-Learning Traffic Classification Based on FlowCharacteristics (2004)
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 4
![Page 16: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/16.jpg)
CISCO supported work
Exploring the efficacy of distributed statistical trafficclassification using modified open source packet filters(2010)Implementing and testing delay-based and rate-basedtransport protocols in FreeBSD (2008)Heuristics to reduce BGP Update Noise (2007)
FreeBSD Implementation of an SCTP friendly NAT (2007)Anomalous Traffic Detection and Collaborative NetworkConfiguration Using 3D Multiplayer Game Engines (2006)Public Implementation and Interoperability Testing of NextGeneration TCP Stack Under FreeBSD (2005)Dynamic Self-Learning Traffic Classification Based on FlowCharacteristics (2004)
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 4
![Page 17: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/17.jpg)
CISCO supported work
Exploring the efficacy of distributed statistical trafficclassification using modified open source packet filters(2010)Implementing and testing delay-based and rate-basedtransport protocols in FreeBSD (2008)Heuristics to reduce BGP Update Noise (2007)FreeBSD Implementation of an SCTP friendly NAT (2007)
Anomalous Traffic Detection and Collaborative NetworkConfiguration Using 3D Multiplayer Game Engines (2006)Public Implementation and Interoperability Testing of NextGeneration TCP Stack Under FreeBSD (2005)Dynamic Self-Learning Traffic Classification Based on FlowCharacteristics (2004)
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 4
![Page 18: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/18.jpg)
CISCO supported work
Exploring the efficacy of distributed statistical trafficclassification using modified open source packet filters(2010)Implementing and testing delay-based and rate-basedtransport protocols in FreeBSD (2008)Heuristics to reduce BGP Update Noise (2007)FreeBSD Implementation of an SCTP friendly NAT (2007)Anomalous Traffic Detection and Collaborative NetworkConfiguration Using 3D Multiplayer Game Engines (2006)
Public Implementation and Interoperability Testing of NextGeneration TCP Stack Under FreeBSD (2005)Dynamic Self-Learning Traffic Classification Based on FlowCharacteristics (2004)
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 4
![Page 19: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/19.jpg)
CISCO supported work
Exploring the efficacy of distributed statistical trafficclassification using modified open source packet filters(2010)Implementing and testing delay-based and rate-basedtransport protocols in FreeBSD (2008)Heuristics to reduce BGP Update Noise (2007)FreeBSD Implementation of an SCTP friendly NAT (2007)Anomalous Traffic Detection and Collaborative NetworkConfiguration Using 3D Multiplayer Game Engines (2006)Public Implementation and Interoperability Testing of NextGeneration TCP Stack Under FreeBSD (2005)
Dynamic Self-Learning Traffic Classification Based on FlowCharacteristics (2004)
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 4
![Page 20: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/20.jpg)
CISCO supported work
Exploring the efficacy of distributed statistical trafficclassification using modified open source packet filters(2010)Implementing and testing delay-based and rate-basedtransport protocols in FreeBSD (2008)Heuristics to reduce BGP Update Noise (2007)FreeBSD Implementation of an SCTP friendly NAT (2007)Anomalous Traffic Detection and Collaborative NetworkConfiguration Using 3D Multiplayer Game Engines (2006)Public Implementation and Interoperability Testing of NextGeneration TCP Stack Under FreeBSD (2005)Dynamic Self-Learning Traffic Classification Based on FlowCharacteristics (2004)
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 4
![Page 21: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/21.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmission
the congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:
delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:
Send rate > receive rate =⇒ indicates congestion
Basic questions:
How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 22: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/22.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:
delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:
Send rate > receive rate =⇒ indicates congestion
Basic questions:
How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 23: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/23.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:
delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:
Send rate > receive rate =⇒ indicates congestion
Basic questions:
How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 24: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/24.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:
delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:
Send rate > receive rate =⇒ indicates congestion
Basic questions:
How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 25: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/25.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:
Send rate > receive rate =⇒ indicates congestion
Basic questions:
How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 26: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/26.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:
Send rate > receive rate =⇒ indicates congestion
Basic questions:
How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 27: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/27.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:Send rate > receive rate =⇒ indicates congestion
Basic questions:
How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 28: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/28.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:Send rate > receive rate =⇒ indicates congestion
Basic questions:
How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 29: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/29.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:Send rate > receive rate =⇒ indicates congestion
Basic questions:How is congestion determined?
and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 30: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/30.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:Send rate > receive rate =⇒ indicates congestion
Basic questions:How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 31: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/31.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:Send rate > receive rate =⇒ indicates congestion
Basic questions:How is congestion determined?and if congested, how should cwnd be adjusted
Issues:
Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
![Page 32: Delay-Based TCP Congestion Control - Universitetet i oslofolk.uio.no/davihay/hayes10__cisco_delay_based_tcp_conges_contr.pdf · Heuristics to reduce BGP Update Noise (2007) FreeBSD](https://reader031.vdocuments.us/reader031/viewer/2022030405/5a7b5fb57f8b9a49588bdca2/html5/thumbnails/32.jpg)
Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:Send rate > receive rate =⇒ indicates congestion
Basic questions:How is congestion determined?and if congested, how should cwnd be adjusted
Issues:Noise of measurements
Correlation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
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Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:Send rate > receive rate =⇒ indicates congestion
Basic questions:How is congestion determined?and if congested, how should cwnd be adjusted
Issues:Noise of measurementsCorrelation of measurements with congestion
Compatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
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Introduction to delay and rate based TCP
Promise of low latency zero loss1 transmissionthe congestion signal can be decoupled from packet loss
potential for efficient transmission on lossy paths.
Delay based intuition:delay↑ ≡ queue↑ =⇒ indicates congestion
Rate based intuition:Send rate > receive rate =⇒ indicates congestion
Basic questions:How is congestion determined?and if congested, how should cwnd be adjusted
Issues:Noise of measurementsCorrelation of measurements with congestionCompatibility with existing TCP algorithms
1congestion related
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 5
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Background – TCP’s Congestion Window (w)In general loss-based TCP:
increases w by the maximum segment size every RTT
or 1/w for every ACK
and halves w when a packet has been lost.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 6
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Background – TCP’s Congestion Window (w)In general loss-based TCP:
increases w by the maximum segment size every RTT
or 1/w for every ACK
and halves w when a packet has been lost.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 6
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Background – TCP’s Congestion Window (w)In general loss-based TCP:
increases w by the maximum segment size every RTTor 1/w for every ACK
and halves w when a packet has been lost.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 6
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Background – TCP’s Congestion Window (w)In general loss-based TCP:
increases w by the maximum segment size every RTTor 1/w for every ACK
and halves w when a packet has been lost.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 6
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Background – TCP’s Congestion Window (w)In general loss-based TCP:
increases w by the maximum segment size every RTTor 1/w for every ACK
and halves w when a packet has been lost.
wi+1 =
{wi2 lost packetwi + 1
wiotherwise
20 25 30 35 40 45 500
20
40
60
80
100
120
time (s)
cw
nd (
packets
)
NewReno
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Background: Base timing measurements
drw
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
rttmin
dsw
rttmax
rtt1
daw ≈ drw
dS1
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Background: Base timing measurements
dS1
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
rttmin
dsw
rttmax
rtt1
daw ≈ drw
drw
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 7
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Background: Base timing measurements
dsw
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
rttmin
rttmax
rtt1
daw ≈ drw
drw
dS1
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Background: Base timing measurements
drw
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
rttmin
rttmax
rtt1
daw ≈ drw
dS1dsw
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Background: Base timing measurements
daw ≈ drw
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
rttmin
rttmax
rtt1
dS1dsw
drw
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Background: Base timing measurements
rtt1
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
rttmin
rttmax
dS1dsw
drw
daw ≈ drw
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 7
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Background: Base timing measurements
dS1
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
dsw
drw
daw ≈ drw
rtt1
rttmin
rttmax
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 7
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Background: Base timing measurements
Note: Queueing atFIFO network nodescan increase ordecrease theinterpacket times
daw
SS
S
SS
S
SA
A
A
AA
d ′aw
d ′′aw
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Background: Base timing measurements
Note: Queueing atFIFO network nodescan increase ordecrease theinterpacket times
daw
SS
S
SS
S
SA
A
A
AA
d ′′aw
d ′aw
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Background: Base timing measurements
Note: Queueing atFIFO network nodescan increase ordecrease theinterpacket times
daw
SS
S
SS
S
SA
A
A
AA
d ′aw
d ′′aw
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 8
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Background: Base timing measurements
Note: Queueing atFIFO network nodescan increase ordecrease theinterpacket times
daw
SS
S
SS
S
SA
A
A
AA
d ′aw
d ′′aw
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Background: Base rate measurements
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Background: Base rate measurements
Ra =∑w−a1 Ai
daw
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
T1 =∑w S
rtt1
Tmax =∑w Srttmin
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Background: Base rate measurements
T1 =∑w S
rtt1
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
Tmax =∑w Srttmin
Ra =∑w−a1 Ai
daw
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Background: Base rate measurements
Tmax =∑w Srttmin
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
Ra =∑w−a1 Ai
daw
T1 =∑w S
rtt1
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 9
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Background: Base rate measurements
Ra =∑w−a1 Ai
daw
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
T1 =∑w S
rtt1
Tmax =∑w Srttmin
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Background: Base rate measurements
T1 =∑w S
rtt1
S1
S2
S3
S4
S5
A1
A2A3
A4A5
S6S7S8S9
Tmax =∑w Srttmin
Ra =∑w−a1 Ai
daw
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 9
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Quick early work overview[Clark et al., 1985]&[Clark et al., 1987] NETBLT RFCs 996&998
[Jacobson, 1988]a – footnote on connectionless rate based AIMD.[Jain, 1989]b normalised delay gradient.[Wang and Crowcroft, 1992]c DUAL algorithm.[Brakmo and Peterson, 1995]d TCP Vegas.
aV. Jacobson, “Congestion avoidance and control,” in SIGCOMM ’88: Symposiumproceedings on Communications architectures and protocols. New York, NY, USA:ACM, 1988, pp. 314–329
bR. Jain, “A delay-based approach for congestion avoidance in interconnectedheterogeneous computer networks,” SIGCOMM Comput. Commun. Rev., vol. 19, no. 5,pp. 56–71, 1989
cZ. Wang and J. Crowcroft, “Eliminating periodic packet losses in the 4.3-TahoeBSD TCP congestion control algorithm,” SIGCOMM Comput. Commun. Rev., vol. 22,no. 2, pp. 9–16, Apr. 1992
dL. S. Brakmo and L. L. Peterson, “TCP Vegas: end to end congestion avoidance ona global internet,” IEEE J. Sel. Areas Commun., vol. 13, no. 8, pp. 1465–1480, Oct.1995
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Quick early work overview[Clark et al., 1985]&[Clark et al., 1987] NETBLT RFCs 996&998[Jacobson, 1988]a – footnote on connectionless rate based AIMD.
[Jain, 1989]b normalised delay gradient.[Wang and Crowcroft, 1992]c DUAL algorithm.[Brakmo and Peterson, 1995]d TCP Vegas.
aV. Jacobson, “Congestion avoidance and control,” in SIGCOMM ’88: Symposiumproceedings on Communications architectures and protocols. New York, NY, USA:ACM, 1988, pp. 314–329
bR. Jain, “A delay-based approach for congestion avoidance in interconnectedheterogeneous computer networks,” SIGCOMM Comput. Commun. Rev., vol. 19, no. 5,pp. 56–71, 1989
cZ. Wang and J. Crowcroft, “Eliminating periodic packet losses in the 4.3-TahoeBSD TCP congestion control algorithm,” SIGCOMM Comput. Commun. Rev., vol. 22,no. 2, pp. 9–16, Apr. 1992
dL. S. Brakmo and L. L. Peterson, “TCP Vegas: end to end congestion avoidance ona global internet,” IEEE J. Sel. Areas Commun., vol. 13, no. 8, pp. 1465–1480, Oct.1995
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Quick early work overview[Clark et al., 1985]&[Clark et al., 1987] NETBLT RFCs 996&998[Jacobson, 1988]a – footnote on connectionless rate based AIMD.[Jain, 1989]b normalised delay gradient.
[Wang and Crowcroft, 1992]c DUAL algorithm.[Brakmo and Peterson, 1995]d TCP Vegas.
aV. Jacobson, “Congestion avoidance and control,” in SIGCOMM ’88: Symposiumproceedings on Communications architectures and protocols. New York, NY, USA:ACM, 1988, pp. 314–329
bR. Jain, “A delay-based approach for congestion avoidance in interconnectedheterogeneous computer networks,” SIGCOMM Comput. Commun. Rev., vol. 19, no. 5,pp. 56–71, 1989
cZ. Wang and J. Crowcroft, “Eliminating periodic packet losses in the 4.3-TahoeBSD TCP congestion control algorithm,” SIGCOMM Comput. Commun. Rev., vol. 22,no. 2, pp. 9–16, Apr. 1992
dL. S. Brakmo and L. L. Peterson, “TCP Vegas: end to end congestion avoidance ona global internet,” IEEE J. Sel. Areas Commun., vol. 13, no. 8, pp. 1465–1480, Oct.1995
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Quick early work overview[Clark et al., 1985]&[Clark et al., 1987] NETBLT RFCs 996&998[Jacobson, 1988]a – footnote on connectionless rate based AIMD.[Jain, 1989]b normalised delay gradient.[Wang and Crowcroft, 1992]c DUAL algorithm.
[Brakmo and Peterson, 1995]d TCP Vegas.
aV. Jacobson, “Congestion avoidance and control,” in SIGCOMM ’88: Symposiumproceedings on Communications architectures and protocols. New York, NY, USA:ACM, 1988, pp. 314–329
bR. Jain, “A delay-based approach for congestion avoidance in interconnectedheterogeneous computer networks,” SIGCOMM Comput. Commun. Rev., vol. 19, no. 5,pp. 56–71, 1989
cZ. Wang and J. Crowcroft, “Eliminating periodic packet losses in the 4.3-TahoeBSD TCP congestion control algorithm,” SIGCOMM Comput. Commun. Rev., vol. 22,no. 2, pp. 9–16, Apr. 1992
dL. S. Brakmo and L. L. Peterson, “TCP Vegas: end to end congestion avoidance ona global internet,” IEEE J. Sel. Areas Commun., vol. 13, no. 8, pp. 1465–1480, Oct.1995
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Quick early work overview[Clark et al., 1985]&[Clark et al., 1987] NETBLT RFCs 996&998[Jacobson, 1988]a – footnote on connectionless rate based AIMD.[Jain, 1989]b normalised delay gradient.[Wang and Crowcroft, 1992]c DUAL algorithm.[Brakmo and Peterson, 1995]d TCP Vegas.
aV. Jacobson, “Congestion avoidance and control,” in SIGCOMM ’88: Symposiumproceedings on Communications architectures and protocols. New York, NY, USA:ACM, 1988, pp. 314–329
bR. Jain, “A delay-based approach for congestion avoidance in interconnectedheterogeneous computer networks,” SIGCOMM Comput. Commun. Rev., vol. 19, no. 5,pp. 56–71, 1989
cZ. Wang and J. Crowcroft, “Eliminating periodic packet losses in the 4.3-TahoeBSD TCP congestion control algorithm,” SIGCOMM Comput. Commun. Rev., vol. 22,no. 2, pp. 9–16, Apr. 1992
dL. S. Brakmo and L. L. Peterson, “TCP Vegas: end to end congestion avoidance ona global internet,” IEEE J. Sel. Areas Commun., vol. 13, no. 8, pp. 1465–1480, Oct.1995
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A quick look at somekey/interesting algorithms in
the literature
Centre for Advanced Internet Architectures (CAIA)Swinburne University of Technology
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairsAvailable send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
network nodeSOURCE
p
2
BOTTLENECK
t
disperionpair
estimate
p1
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
network nodeSOURCE
p
2
BOTTLENECK
t
disperionpair
estimate
p1
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
network nodeSOURCE
p
2
BOTTLENECK
t
disperionpair
estimate
p1
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
SOURCE network node
1p
2
BOTTLENECK
t
disperionpair
estimate
p
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
network nodeSOURCE
p
2
BOTTLENECK
t
disperionpair
estimate
p1
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
SOURCE network node
1p
2
BOTTLENECK
t
disperionpair
estimate
p
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
network nodeSOURCE
pair
1p
2
BOTTLENECK
t
estimate
disperion
p
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairs
Available send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
SOURCE network node BOTTLENECK
1p
2
p t
estimate
disperionpair
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairsAvailable send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
SOURCE network node BOTTLENECK
1p
2
p t
estimate
disperionpair
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Pkt pair flow control [Keshav, 1994]
All data is sent asback-to-back pairsAvailable send rate is:
T =size(p2)
pair dispersion
Presumes routers useround robin scheduling
pair
disperion
SOURCE network node BOTTLENECK
1p
2
p t
estimate
disperionpair
SINK
RTT
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 12
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:window adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCP
Defines two rates:window adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:
window adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:
actual =
∑S
rtt
window adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
S1
S2
S3
S4
S5
rtt1
A1
∑S
rttmin
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:
actual =
∑S
rtt
expected =w
rttmin
window adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
S1
S2
S3
S4
S5
A1
rtt1
∑S
rttmin
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:
actual =
∑S
rtt
expected =w
rttmin
and diff = expected− actual
window adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
S1
S2
S3
S4
S5
A1
rtt1
∑S
rttmin
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:
actual =
∑S
rtt
expected =w
rttmin
and diff = expected− actualwindow adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
S1
S2
S3
S4
S5
A1
rtt1
∑S
rttmin
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:
actual =
∑S
rtt
expected =w
rttmin
and diff = expected− actualwindow adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
S1
S2
S3
S4
S5
A1
rtt1
∑S
rttmin
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:
actual =
∑S
rtt
expected =w
rttmin
and diff = expected− actualwindow adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
S1
S2
S3
S4
S5
A1
rtt1
∑S
rttmin
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: Vegas [Brakmo and Peterson, 1995]
Iconic rate based TCPDefines two rates:
actual =
∑S
rtt
expected =w
rttmin
and diff = expected− actualwindow adjustment:
w ←
w − 1 diff > β
w + 1 diff < α
w otherwise
S1
S2
S3
S4
S5
A1
rtt1
∑S
rttmin
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 13
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithm
MIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networks
Uses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicator
Cwnd is updated at regular time intervals (∆t):For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):
For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):
wt+∆t = min{
2wt , γ
(rttmin,i
rttiwt + α
)+ (1− γ)wt
}
For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):
wt+∆t = min{
2wt , γ
(rttmin,i
rttiwt + α
)+ (1− γ)wt
}Smoothed window increase
For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):
wt+∆t = min{
2wt , γ
(rttmin,i
rttiwt + α
)+ (1− γ)wt
}When congested, decreases in proportion to queueing
delay
For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):
wt+∆t = min{
2wt , γ
(rttmin,i
rttiwt + α
)+ (1− γ)wt
}increase is limited to 2w per ∆t
For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):
wt+∆t = min{
2wt , γ
(rttmin,i
rttiwt + α
)+ (1− γ)wt
}
For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: FAST [Wei et al., 2006]
Enhanced Vegas type algorithmMIMD — AIMD to slow for high BDP networksUses delay as a rich (non binary) congestion indicatorCwnd is updated at regular time intervals (∆t):
wt+∆t = min{
2wt , γ
(rttmin,i
rttiwt + α
)+ (1− γ)wt
}
For MIMD, α(wt ,qi)
increase is proportional to the size of cwnd and the networkqueueing delay.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 14
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:
efficiencyRTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughput
The send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwndand dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiency
RTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughput
The send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwndand dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiencyRTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughput
The send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwndand dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiencyRTT fairness and TCP fairness
In MSW Vista and 7
Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughput
The send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwndand dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiencyRTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughput
The send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwndand dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiencyRTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughput
The send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwndand dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiencyRTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughputThe send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )
where wj is NewReno’s cwndand dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiencyRTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughputThe send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwnd
and dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiencyRTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughputThe send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwndand dwndj is the delay based window.
and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: Compound TCP [Tan et al., 2006]
In high speed high BDP networks aims to increase:efficiencyRTT fairness and TCP fairness
In MSW Vista and 7Uses Vegas’ rates: diff = (expected− actual)rttmin
Provides NewReno+ performance throughputThe send window, winj , is calculated as:winj = min(wj + dwndj ,awndj )where wj is NewReno’s cwndand dwndj is the delay based window.and awndj is the receivers advertised window.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 15
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Algorithms: DUAL [Wang and Crowcroft, 1992]
Designed to supplement loss based congestion control
Delay based measurements provide “slow tuning” of cwndevery 2nd RTT
w ←
{βw rtt > (rttmin+rttmax)
2
w otherwise
where β = 78
Attempts to keep network buffers half fullSmaller multiplicative decreaseRelies on accurate estimates of rttmin and rttmax
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 16
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Algorithms: DUAL [Wang and Crowcroft, 1992]
Designed to supplement loss based congestion controlDelay based measurements provide “slow tuning” of cwndevery 2nd RTT
w ←
{βw rtt > (rttmin+rttmax)
2
w otherwise
where β = 78
Attempts to keep network buffers half fullSmaller multiplicative decreaseRelies on accurate estimates of rttmin and rttmax
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 16
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Algorithms: DUAL [Wang and Crowcroft, 1992]
Designed to supplement loss based congestion controlDelay based measurements provide “slow tuning” of cwndevery 2nd RTT
w ←
{βw rtt > (rttmin+rttmax)
2
w otherwise
where β = 78
Attempts to keep network buffers half full
Smaller multiplicative decreaseRelies on accurate estimates of rttmin and rttmax
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 16
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Algorithms: DUAL [Wang and Crowcroft, 1992]
Designed to supplement loss based congestion controlDelay based measurements provide “slow tuning” of cwndevery 2nd RTT
w ←
{βw rtt > (rttmin+rttmax)
2
w otherwise
where β = 78
Attempts to keep network buffers half fullSmaller multiplicative decrease
Relies on accurate estimates of rttmin and rttmax
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 16
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Algorithms: DUAL [Wang and Crowcroft, 1992]
Designed to supplement loss based congestion controlDelay based measurements provide “slow tuning” of cwndevery 2nd RTT
w ←
{βw rtt > (rttmin+rttmax)
2
w otherwise
where β = 78
Attempts to keep network buffers half fullSmaller multiplicative decreaseRelies on accurate estimates of rttmin and rttmax
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 16
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Algorithms: Others of Interest
[King et al., 2005] — TCP-Africa
Two modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCP
Yet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.
Compound TCP is based on some of Africa’s ideas[Baiocchi et al., 2007] — YeAH-TCP
Yet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCP
Yet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCP
Yet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCPYet Another Highspeed TCP
Two modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCPYet Another Highspeed TCPTwo modes like Africa
Provides performance improvements on lossy paths.A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCPYet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCPYet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCPYet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like
[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCPYet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket
[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Algorithms: Others of Interest
[King et al., 2005] — TCP-AfricaTwo modes: Fast delay based, and slow NewReno based.Compound TCP is based on some of Africa’s ideas
[Baiocchi et al., 2007] — YeAH-TCPYet Another Highspeed TCPTwo modes like AfricaProvides performance improvements on lossy paths.
A number of schemes propose traffic shaping TCP’s sendrate
[Karandikar et al., 2000] – ABR like[Wu et al., 2002] – leaky bucket[Abendroth et al., 2002] – improved leaky bucket for networkburstiness.
CISCO http://www.caia.swin.edu.au [email protected] 15 October, 2010 17
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Improved coexistence andloss tolerance for
delay basedTCP congestion control
Best Paper Award LCN 2010
David Hayes and Grenville Armitage
{dahayes,garmitage}@swin.edu.au
Centre for Advanced Internet Architectures (CAIA)Swinburne University of Technology
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Introduction
Delay-based congestion control can potentially provide:
low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.
efficient TCP over lossy paths (wireless links).
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
Issues:
Measuring delay to infer congestionCoexistence with current loss-based TCP
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
Issues:Measuring delay to infer congestion
Coexistence with current loss-based TCP
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
Issues:Measuring delay to infer congestionCoexistence with current loss-based TCP
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
Issues:Measuring delay to infer congestionCoexistence with current loss-based TCP
We propose a delay based algorithm which:
improves TCP efficiency over lossy pathsimproves coexistence with loss-based TCPimplement algorithms in the FreeBSD kernel
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
Issues:Measuring delay to infer congestionCoexistence with current loss-based TCP
We propose a delay based algorithm which:
improves TCP efficiency over lossy paths
improves coexistence with loss-based TCPimplement algorithms in the FreeBSD kernel
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
Issues:Measuring delay to infer congestionCoexistence with current loss-based TCP
We propose a delay based algorithm which:
improves TCP efficiency over lossy pathsimproves coexistence with loss-based TCP
implement algorithms in the FreeBSD kernel
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Introduction
Delay-based congestion control can potentially provide:low latency transmission no congestion induced packet loss.efficient TCP over lossy paths (wireless links).
Issues:Measuring delay to infer congestionCoexistence with current loss-based TCP
We propose a delay based algorithm which:
improves TCP efficiency over lossy pathsimproves coexistence with loss-based TCPimplement algorithms in the FreeBSD kernel
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 19
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Hamilton Delay (HD) based window updates[Budzisz et al., 2009]
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 20
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Hamilton Delay (HD) based window updates[Budzisz et al., 2009]Probabilistic delay-based backoff (coexistence)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 20
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Hamilton Delay (HD) based window updates[Budzisz et al., 2009]Probabilistic delay-based backoff (coexistence)
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qth
g(q)
qmax
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 20
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Hamilton Delay (HD) based window updates[Budzisz et al., 2009]Probabilistic delay-based backoff (coexistence)
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qth
g(q)
qmax
wi+1 =
{wi2 X < g(qi)
wi + 1wi
otherwise
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 20
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Hamilton Delay (HD) based window updates[Budzisz et al., 2009]Probabilistic delay-based backoff (coexistence)
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qth
g(q)
qmax
wi+1 =
{wi2 X < g(qi)
wi + 1wi
otherwise
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 20
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Hamilton Delay (HD) based window updates[Budzisz et al., 2009]Probabilistic delay-based backoff (coexistence)
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qmax
g(q)
qth
wi+1 =
{wi2 X < g(qi)
wi + 1wi
otherwise
Region A stable when queueing delay is low
Region B only stable when queueing delay is high
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 20
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Hamilton Delay (HD) based window updates[Budzisz et al., 2009]Probabilistic delay-based backoff (coexistence)
delayQueuing
probabilitybackoff
A
Per−packet
B
backoff probability
pmax
qmin qmax
g(q)
qth
wi+1 =
{wi2 X < g(qi)
wi + 1wi
otherwise
Region A stable when queueing delay is lowRegion B only stable when queueing delay is high
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 20
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RTT – loss-based & delay-based congestion control
20 25 30 35 40 45 5040
60
80
100
120
140
RT
T (
s)
Time (s)
NewReno
20 25 30 35 40 45 5040
60
80
100
120
140
RT
T (
s)
Time (s)
Hamilton
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 21
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Delay-based back-off decision frequency
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qth
g(q)
qmax
HD decision per packet:
Doesn’t scale well:
P[backoff] increases with w
CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Delay-based back-off decision frequency
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qth
g(q)
qmax
HD decision per packet:
Doesn’t scale well:
P[backoff] increases with w
CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Delay-based back-off decision frequency
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qth
g(q)
qmax
HD decision per packet:Doesn’t scale well:
P[backoff] increases with w
CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Delay-based back-off decision frequency
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qth
g(q)
qmax
HD decision per packet:Doesn’t scale well:
P[backoff] increases with w
CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Delay-based back-off decision frequency
delayQueuing
probabilitybackoff
B
Per−packet
A
backoff probability
pmax
qmin qth
g(q)
qmax
HD decision per packet:Doesn’t scale well:
P[backoff] increases with w
CPU
CHD decision once per RTT
Uses hr = maxr (qi)
Scales with wless CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Delay-based back-off decision frequencyPer−RTT
delayQueuing
probabilitybackoff
A B
backoff probability
qmax
pmax
qmin qth
g(hr)
HD decision per packet:Doesn’t scale well:
P[backoff] increases with w
CPU
CHD decision once per RTT
Uses hr = maxr (qi)
Scales with wless CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Delay-based back-off decision frequencyPer−RTT
delayQueuing
probabilitybackoff
A B
backoff probability
qmax
pmax
qmin qth
g(hr)
HD decision per packet:Doesn’t scale well:
P[backoff] increases with w
CPU
CHD decision once per RTT
Uses hr = maxr (qi)
Scales with wless CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Delay-based back-off decision frequencyPer−RTT
delayQueuing
probabilitybackoff
A B
backoff probability
qmax
pmax
qmin qth
g(hr)
HD decision per packet:Doesn’t scale well:
P[backoff] increases with w
CPU
CHD decision once per RTT
Uses hr = maxr (qi)
Scales with w
less CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Delay-based back-off decision frequencyPer−RTT
delayQueuing
probabilitybackoff
A B
backoff probability
qmax
pmax
qmin qth
g(hr)
HD decision per packet:Doesn’t scale well:
P[backoff] increases with w
CPU
CHD decision once per RTT
Uses hr = maxr (qi)
Scales with wless CPU
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 22
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Tolerance to non-congestion related packet loss
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 23
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Tolerance to non-congestion related packet loss
HD (and NewReno) do not tolerate packet loss
w = w/2 when a packet is lost
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 23
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Tolerance to non-congestion related packet loss
HD (and NewReno) do not tolerate packet loss
w = w/2 when a packet is lost
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 23
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Tolerance to non-congestion related packet loss
HD (and NewReno) do not tolerate packet loss
w = w/2 when a packet is lost
CHD tolerates low level packet loss well by:
Ignoring packet loss when queueing delays are small(region A)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 23
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Tolerance to non-congestion related packet loss
HD (and NewReno) do not tolerate packet loss
w = w/2 when a packet is lost
CHD tolerates low level packet loss well by:Ignoring packet loss when queueing delays are small(region A)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 23
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Tolerance to non-congestion related packet loss
HD (and NewReno) do not tolerate packet loss
w = w/2 when a packet is lost
CHD tolerates low level packet loss well by:Ignoring packet loss when queueing delays are small(region A)
delayQueuing
probabilitybackoff
B
Per−RTTbackoff probability
A
qthqmin
pmax
g(hr)
qmax
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 23
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Tolerance to non-congestion related losses
0 0.01 0.02 0.03 0.04 0.050
2
4
6
8
10x 10
6
Goodput (b
ps)
Probability of non−congestion related loss
NewReno
HD
CHD
1/sqrt(p)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 24
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Improving coexistence with loss-based TCP
To improve CHD’s coexistence ability
React only to packet loss in region BWe use a shadow window (s) (shadows NewReno)
On packet loss, wi+1 = max(wi ,si )2
Best explained with an example
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 25
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Improving coexistence with loss-based TCP
To improve CHD’s coexistence ability
React only to packet loss in region BWe use a shadow window (s) (shadows NewReno)
On packet loss, wi+1 = max(wi ,si )2
Best explained with an example
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 25
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Improving coexistence with loss-based TCP
To improve CHD’s coexistence abilityReact only to packet loss in region B
We use a shadow window (s) (shadows NewReno)
On packet loss, wi+1 = max(wi ,si )2
delayQueuing
probabilitybackoff
B
Per−RTTbackoff probability
A
qmax
pmax
qmin qth
g(hr)
Best explained with an example
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 25
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Improving coexistence with loss-based TCP
To improve CHD’s coexistence abilityReact only to packet loss in region BWe use a shadow window (s) (shadows NewReno)
On packet loss, wi+1 = max(wi ,si )2
delayQueuing
probabilitybackoff
B
Per−RTTbackoff probability
A
qmax
pmax
qmin qth
g(hr)
Best explained with an example
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 25
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Improving coexistence with loss-based TCP
To improve CHD’s coexistence abilityReact only to packet loss in region BWe use a shadow window (s) (shadows NewReno)
On packet loss, wi+1 = max(wi ,si )2
delayQueuing
probabilitybackoff
B
Per−RTTbackoff probability
A
qmax
pmax
qmin qth
g(hr)
Best explained with an example
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 25
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Improving coexistence with loss-based TCP
To improve CHD’s coexistence abilityReact only to packet loss in region BWe use a shadow window (s) (shadows NewReno)
On packet loss, wi+1 = max(wi ,si )2
delayQueuing
probabilitybackoff
B
Per−RTTbackoff probability
A
qmax
pmax
qmin qth
g(hr)
Best explained with an example
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 25
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Shadow window example
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
number of round trip times
w
s = 0
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
delay based congestion
number of round trip times
w
s = 0
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
delay based congestion
number of round trip times
s sync
w
s
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
delay based congestion
number of round trip times
s sync
w
s
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
delay based congestion
number of round trip times
lost packets sync
w
w recovery
s
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
delay based congestion
number of round trip times
lost packets sync
w
w recovery
s
Region B
max(wi , si)
2
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
delay based congestion
number of round trip times
lost packets sync
w
w recovery
without w recovery
s
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
delay based congestion
number of round trip times
lost packets sync
w
w recovery
without w recovery
transmissionlost
opportunity
s
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Shadow window examplep
ack
ets
delay based congestion
number of round trip times
lost packets sync
w
w recovery
without w recovery
transmissionlost
opportunity gainedtransmissionopportunity
s
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 26
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Testbed for coexistence tests
(FreeBSD)
20ms
20ms
NewReno Sources(FreeBSD)
Delay CC Sources(FreeBSD)
Delay CC Sink
NewReno Sink(FreeBSD)
(FreeBSD)
Dummynet Router
We will look at HD and CHD coexisting with NewRenoFor 0 % and 1 % non-congestion related losses
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 27
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Testbed for coexistence tests
(FreeBSD)
20ms
20ms
NewReno Sources(FreeBSD)
Delay CC Sources(FreeBSD)
Delay CC Sink
NewReno Sink(FreeBSD)
(FreeBSD)
Dummynet Router
We will look at HD and CHD coexisting with NewReno
For 0 % and 1 % non-congestion related losses
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 27
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Testbed for coexistence tests
(FreeBSD)
20ms
20ms
NewReno Sources(FreeBSD)
Delay CC Sources(FreeBSD)
Delay CC Sink
NewReno Sink(FreeBSD)
(FreeBSD)
Dummynet Router
We will look at HD and CHD coexisting with NewRenoFor 0 % and 1 % non-congestion related losses
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 27
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HD coexisting with NewReno (1s Av, 0 % loss)
0 20 40 60 80 100 120 1400
2
4
6
8
10x 10
6
Time (s)
Go
od
pu
t (b
ps)
HD NewReno NewReno HD
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 28
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HD coexisting with NewReno (1s Av, 0 % loss)
0 20 40 60 80 100 120 1400
2
4
6
8
10x 10
6
Time (s)
Go
od
pu
t (b
ps)
HD NewReno NewReno HD
HD does not compete well with NewReno
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 28
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CHD coexisting with NewReno (1s Av, 0 % loss)
0 20 40 60 80 100 120 1400
2
4
6
8
10x 10
6
Time (s)
Go
od
pu
t (b
ps)
CHD NewReno NewReno CHD
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 28
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CHD coexisting with NewReno (1s Av, 0 % loss)
0 20 40 60 80 100 120 1400
2
4
6
8
10x 10
6
Time (s)
Go
od
pu
t (b
ps)
CHD NewReno NewReno CHD
CHD reclaims some of the lost capacity from NewReno
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 28
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Coexiting with NewReno on a lossy path
1 % loss5 s averages
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 29
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HD coexisting with NewReno (5s Av, 1 % loss)
0 20 40 60 80 100 120 1400
2
4
6
8
10x 10
6
Time (s)
Go
od
pu
t (b
ps)
HDNewRenoNewRenoHD
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 29
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HD coexisting with NewReno (5s Av, 1 % loss)
0 20 40 60 80 100 120 1400
2
4
6
8
10x 10
6
Time (s)
Go
od
pu
t (b
ps)
HDNewRenoNewRenoHD
HD and NewReno cannot efficiently utilise the availablebandwidth
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 29
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CHD coexisting with NewReno (5s Av, 1 % loss)
0 20 40 60 80 100 120 1400
2
4
6
8
10x 10
6
Time (s)
Go
od
pu
t (b
ps)
CHDNewRenoNewRenoCHD
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 29
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CHD coexisting with NewReno (5s Av, 1 % loss)
0 20 40 60 80 100 120 1400
2
4
6
8
10x 10
6
Time (s)
Go
od
pu
t (b
ps)
CHDNewRenoNewRenoCHD
CHD is able to effectively use the available bandwidth(including what NewReno is unable to use)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 29
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LCN Conclusions
CHD significantly enhances HD:improves scalability with per RTT decisions
improves tolerance to non-congestion related packet lossesimproves coexistence with loss based TCP (NewReno)
Shadow windowLightly multiplexed environments
CHD and HD have been implemented in the FreeBSD kernel(caia.swin.edu.au/urp/newtcp/tools.html)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 30
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LCN Conclusions
CHD significantly enhances HD:improves scalability with per RTT decisionsimproves tolerance to non-congestion related packet losses
improves coexistence with loss based TCP (NewReno)
Shadow windowLightly multiplexed environments
CHD and HD have been implemented in the FreeBSD kernel(caia.swin.edu.au/urp/newtcp/tools.html)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 30
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LCN Conclusions
CHD significantly enhances HD:improves scalability with per RTT decisionsimproves tolerance to non-congestion related packet lossesimproves coexistence with loss based TCP (NewReno)
Shadow windowLightly multiplexed environments
CHD and HD have been implemented in the FreeBSD kernel(caia.swin.edu.au/urp/newtcp/tools.html)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 30
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LCN Conclusions
CHD significantly enhances HD:improves scalability with per RTT decisionsimproves tolerance to non-congestion related packet lossesimproves coexistence with loss based TCP (NewReno)
Shadow window
Lightly multiplexed environments
CHD and HD have been implemented in the FreeBSD kernel(caia.swin.edu.au/urp/newtcp/tools.html)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 30
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LCN Conclusions
CHD significantly enhances HD:improves scalability with per RTT decisionsimproves tolerance to non-congestion related packet lossesimproves coexistence with loss based TCP (NewReno)
Shadow windowLightly multiplexed environments
CHD and HD have been implemented in the FreeBSD kernel(caia.swin.edu.au/urp/newtcp/tools.html)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 30
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LCN Conclusions
CHD significantly enhances HD:improves scalability with per RTT decisionsimproves tolerance to non-congestion related packet lossesimproves coexistence with loss based TCP (NewReno)
Shadow windowLightly multiplexed environments
CHD and HD have been implemented in the FreeBSD kernel(caia.swin.edu.au/urp/newtcp/tools.html)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 30
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LCN Conclusions
CHD significantly enhances HD:improves scalability with per RTT decisionsimproves tolerance to non-congestion related packet lossesimproves coexistence with loss based TCP (NewReno)
Shadow windowLightly multiplexed environments
CHD and HD have been implemented in the FreeBSD kernel(caia.swin.edu.au/urp/newtcp/tools.html)
This work was made possible in partby a grant from the Cisco University Research Program Fund
at Community Foundation Silicon Valley
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 30
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A brief look at some otherTCP work at CAIA
David Hayes and Grenville Armitage
{dahayes,garmitage}@swin.edu.au
Centre for Advanced Internet Architectures (CAIA)Swinburne University of Technology
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Delay-gradient based TCP congestion control
We investigated a delay-gradient congestion signalbecause:
it does not require an accurate estimate of base RTTdelay thresholds are hard to set —need to know path’s delay characteristics
We have implemented it in FreeBSD, to be released soon.(waiting on a paper submission)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 32
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Delay-gradient based TCP congestion control
We investigated a delay-gradient congestion signalbecause:
it does not require an accurate estimate of base RTT
delay thresholds are hard to set —need to know path’s delay characteristics
We have implemented it in FreeBSD, to be released soon.(waiting on a paper submission)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 32
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Delay-gradient based TCP congestion control
We investigated a delay-gradient congestion signalbecause:
it does not require an accurate estimate of base RTTdelay thresholds are hard to set —need to know path’s delay characteristics
We have implemented it in FreeBSD, to be released soon.(waiting on a paper submission)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 32
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Delay-gradient based TCP congestion control
We investigated a delay-gradient congestion signalbecause:
it does not require an accurate estimate of base RTTdelay thresholds are hard to set —need to know path’s delay characteristics
We have implemented it in FreeBSD, to be released soon.(waiting on a paper submission)
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 32
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Comparing NewReno and our Delay-GradientTCP RTT dynamics as 3 sources start
NewReno0 20 40 60 80 100
40
60
80
100
120
140
RT
T (
s)
Time (s)
flow 1
flow 2
flow 3
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 33
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Comparing NewReno and our Delay-GradientTCP RTT dynamics as 3 sources start
NewReno
Delay-Gradient
0 20 40 60 80 10040
60
80
100
120
140
RT
T (
s)
Time (s)
flow 1
flow 2
flow 3
0 20 40 60 80 10040
60
80
100
120
140
RT
T (
s)
Time (s)
flow 1
flow 2
flow 3
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 33
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Stateless TCP
Proposed by Geoff Huston to mitigate a DNS server issuehttp://www.potaroo.net/ispcol/2009-11/stateless.pdf
Funded by APNIC and Nominet
DNSSEC may cause the answers to DNS queries to exceeda single UDP packetClients using TCP may overload serversGeoff’s idea→ stateless TCPImplemented in FreeBSD, will be released on the CAIA website in a few weeks.
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 34
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Stateless TCP
Proposed by Geoff Huston to mitigate a DNS server issuehttp://www.potaroo.net/ispcol/2009-11/stateless.pdf
Funded by APNIC and Nominet
DNSSEC may cause the answers to DNS queries to exceeda single UDP packetClients using TCP may overload serversGeoff’s idea→ stateless TCPImplemented in FreeBSD, will be released on the CAIA website in a few weeks.
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 34
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Stateless TCP
Proposed by Geoff Huston to mitigate a DNS server issuehttp://www.potaroo.net/ispcol/2009-11/stateless.pdf
Funded by APNIC and NominetDNSSEC may cause the answers to DNS queries to exceeda single UDP packet
Clients using TCP may overload serversGeoff’s idea→ stateless TCPImplemented in FreeBSD, will be released on the CAIA website in a few weeks.
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 34
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Stateless TCP
Proposed by Geoff Huston to mitigate a DNS server issuehttp://www.potaroo.net/ispcol/2009-11/stateless.pdf
Funded by APNIC and NominetDNSSEC may cause the answers to DNS queries to exceeda single UDP packetClients using TCP may overload servers
Geoff’s idea→ stateless TCPImplemented in FreeBSD, will be released on the CAIA website in a few weeks.
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 34
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Stateless TCP
Proposed by Geoff Huston to mitigate a DNS server issuehttp://www.potaroo.net/ispcol/2009-11/stateless.pdf
Funded by APNIC and NominetDNSSEC may cause the answers to DNS queries to exceeda single UDP packetClients using TCP may overload serversGeoff’s idea→ stateless TCP
Implemented in FreeBSD, will be released on the CAIA website in a few weeks.
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 34
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Stateless TCP
Proposed by Geoff Huston to mitigate a DNS server issuehttp://www.potaroo.net/ispcol/2009-11/stateless.pdf
Funded by APNIC and NominetDNSSEC may cause the answers to DNS queries to exceeda single UDP packetClients using TCP may overload serversGeoff’s idea→ stateless TCPImplemented in FreeBSD, will be released on the CAIA website in a few weeks.
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 34
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Basic stateless TCP idea
if matches hash
DNS server
IP
Data
UDP
send data up
through UDP
statelessTCP
TCP
Listen
Data
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 35
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CPU time versus DNS query arrival rate
0 100 200 300 400 5000
0.5
1
1.5
2
2.5
Average requests/second
CP
U u
sage in 1
0s inte
rval
udp
tcp
stateless
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 36
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Thoughts and conclusions
Delay-based TCP coexistence with loss-based TCP
current schemes coexist by behaving like NewRenoLow latency with no congestion related loss
only when there are no loss-based flows sharing path
If switches and routers could differentiate between loss anddelay based TCP, benefits would be realised sooner.
Delay-gradient as a congestion indication
works wella composite delay-based congestion indication may be better
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 37
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Thoughts and conclusions
Delay-based TCP coexistence with loss-based TCPcurrent schemes coexist by behaving like NewReno
Low latency with no congestion related loss
only when there are no loss-based flows sharing path
If switches and routers could differentiate between loss anddelay based TCP, benefits would be realised sooner.
Delay-gradient as a congestion indication
works wella composite delay-based congestion indication may be better
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 37
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Thoughts and conclusions
Delay-based TCP coexistence with loss-based TCPcurrent schemes coexist by behaving like NewRenoLow latency with no congestion related loss
only when there are no loss-based flows sharing path
If switches and routers could differentiate between loss anddelay based TCP, benefits would be realised sooner.
Delay-gradient as a congestion indication
works wella composite delay-based congestion indication may be better
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 37
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Thoughts and conclusions
Delay-based TCP coexistence with loss-based TCPcurrent schemes coexist by behaving like NewRenoLow latency with no congestion related loss
only when there are no loss-based flows sharing path
If switches and routers could differentiate between loss anddelay based TCP, benefits would be realised sooner.
Delay-gradient as a congestion indication
works wella composite delay-based congestion indication may be better
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 37
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Thoughts and conclusions
Delay-based TCP coexistence with loss-based TCPcurrent schemes coexist by behaving like NewRenoLow latency with no congestion related loss
only when there are no loss-based flows sharing path
If switches and routers could differentiate between loss anddelay based TCP, benefits would be realised sooner.
Delay-gradient as a congestion indication
works wella composite delay-based congestion indication may be better
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 37
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Thoughts and conclusions
Delay-based TCP coexistence with loss-based TCPcurrent schemes coexist by behaving like NewRenoLow latency with no congestion related loss
only when there are no loss-based flows sharing path
If switches and routers could differentiate between loss anddelay based TCP, benefits would be realised sooner.
Delay-gradient as a congestion indication
works wella composite delay-based congestion indication may be better
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 37
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Thoughts and conclusions
Delay-based TCP coexistence with loss-based TCPcurrent schemes coexist by behaving like NewRenoLow latency with no congestion related loss
only when there are no loss-based flows sharing path
If switches and routers could differentiate between loss anddelay based TCP, benefits would be realised sooner.
Delay-gradient as a congestion indicationworks well
a composite delay-based congestion indication may be better
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 37
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Thoughts and conclusions
Delay-based TCP coexistence with loss-based TCPcurrent schemes coexist by behaving like NewRenoLow latency with no congestion related loss
only when there are no loss-based flows sharing path
If switches and routers could differentiate between loss anddelay based TCP, benefits would be realised sooner.
Delay-gradient as a congestion indicationworks wella composite delay-based congestion indication may be better
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 37
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Thank you!
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 38
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Thank you!
Questions?
CISCO http://www.caia.swin.edu.au {dahayes,garmitage}@swin.edu.au 15 October, 2010 38