U Innsbruck Informatik - U Innsbruck Informatik - 1 CADPC/PTP in a nutshell CADPC/PTP in a nutshell Michael Welzl Michael Welzl http://www.welzl.at , , michael [email protected]Distributed and Parallel Systems Group Distributed and Parallel Systems Group Institute of Computer Science Institute of Computer Science University of Innsbruck University of Innsbruck
21
Embed
U Innsbruck Informatik - 1 CADPC/PTP in a nutshell Michael Welzl , [email protected] @uibk.ac.at.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
U Innsbruck Informatik - U Innsbruck Informatik - 11
• 2 consecutive such packets: table of traffic + interval at all routers at receiver• receiver calculates available bandwidth at bottleneck, informs sender
• Designed for flexibility - two modes:– Forward Packet Stamping, Direct Reply (not for available bandwidth (byte
counters))
No problems w/ wireless links!
U Innsbruck Informatik - U Innsbruck Informatik - 66
Forward Packet Stamping: how it Forward Packet Stamping: how it worksworks
U Innsbruck Informatik - U Innsbruck Informatik - 77
Forward Packet Stamping: how it Forward Packet Stamping: how it worksworks
U Innsbruck Informatik - U Innsbruck Informatik - 88
Forward Packet Stamping: how it Forward Packet Stamping: how it worksworks
U Innsbruck Informatik - U Innsbruck Informatik - 99
CADPC: a new CC mechanismCADPC: a new CC mechanism
• “Congestion Avoidance with Distributed Proportional Control“fully distributed convergence to max-min fairness– each source increases/decreases the rate depending on its
capacity share
• Only depends on old rate, smoothness factor and traffic– does not depend on RTT
• Feedback packets can be delayed scalable• reasonable choice: 4 x RTT
• Control realises logistic growth– Asymptotically stable in simplified fluid model with synchronous
RTTs– Smooth convergence to a steady rate
U Innsbruck Informatik - U Innsbruck Informatik - 1010
Some simulation resultsSome simulation results
Many more can be found in:
Michael Welzl, „Scalable Performance Signalling and Congestion Avoidance“, Kluwer Academic Publishers
2003.
U Innsbruck Informatik - U Innsbruck Informatik - 1111
CADPC vs. TCPCADPC vs. TCP
U Innsbruck Informatik - U Innsbruck Informatik - 1212
SmoothnessSmoothness
10 x TFRC 10 x CADPC
U Innsbruck Informatik - U Innsbruck Informatik - 1313
Startup enhancementStartup enhancement
U Innsbruck Informatik - U Innsbruck Informatik - 1414