Transcript Benoit Donnet - INL: IP Networking Lab

Preliminary Analysis of
the TCP Behavior in a
802.16 Network
Jesus A. Perez, Benoit Donnet, Olivier Bonaventure
1st WEIRD Workshop - Coimbra - May 2007
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Wireless Technology
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Wireless Technology (2)
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Wireless Technology (3)
• Incorporates TCP/IP in the protocol stack
• TCP was designed for wired networks
• TCP extensions were proposed for wireless
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TCP Westwood, TCP Jersey, TCP Veno,
J-TCP
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WiMAX
• WiMAX has the potential to serve as
a wireless extension
• an alternative to cable/DSL (last mile/hop
behavior)
WiMAX is supposed to be cheaper and
easily deployed in sparsely populated areas
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•
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WiMAX - Problem
• WiMAX has been essentially evaluated
•
through simulation
Quid of the TCP behavior in a real WiMAX
environment?
• Interest in RTT
• Interest in delay and packet loss
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Testbed
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Measurement setup
• Pre-WiMAX connection hired from a
Belgian provider
• Standard Linux TCP implementation
• BIC TCP with SACK, D-SACK and
FACK
• Downlink measurements
• from LABO to CWIMAX
• both clocks are synchronized
• 10 min. traffic generated by iPerf every 2
hours
• repeated 12 times
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RTT
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Delay - Loss
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Delay - Loss (2)
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Delay - Loss (3)
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Conclusion
• First measurement study of TCP behavior in
•
a real WiMAX environment
• RTT
• Packet loss and delay
One day measurement
•
http://inl.info.ucl.ac.be/files/data-18.11.2006.tar.gz
• This is a first step
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