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SUMMARY:Who am I Competing Against?: Identifying Adversarial     Protocols
  Against TCP in a Congested Link - Idris Rai\, Makerere University\, Ugand
 a
DTSTART:20090716T130000Z
DTEND:20090716T140000Z
UID:TALK18946@talks.cam.ac.uk
CONTACT:Andrew Rice
DESCRIPTION:Classical TCP designs have never considered the identity of th
 e competing transport protocol as useful information to TCP sources in con
 gestion control mechanisms. When competing against a TCP flow on a bottlen
 eck link\, a UDP flow can unfairly occupy the entire link bandwidth and su
 ffocate all TCP flows on the link. If it were possible for a TCP source to
  know the type of the flow that deprives it of link access\, perhaps it wo
 uld be better for the TCP source to\nreact in a way that it avoids starvat
 ion.\n\nIn this talk we use coefficient of variation and power spectral de
 nsity of throughput traces to identify the presence of UDP transport proto
 cols that competes against a TCP flow on a bottleneck link. Our results sh
 ow clear traits that differentiate the presence of competing UDP flows fro
 m TCP flows independent of round trip times variations. Signatures that we
  identified include an increase in coefficient of variation whenever a com
 peting UDP flow joins the bottleneck link for the first time\, noisy spect
 ral density representation of a TCP flow when competing against a UDP flow
  in the bottleneck link\, and a dominant frequency with outstanding power 
 in the presence of TCP competition only. In addition\, the results show th
 at signatures for congestion caused by competing UDP flows are different f
 rom signatures due to congestion caused by competing TCP flows of regardle
 ss their round trip times. The results in this paper present the first ste
 ps towards development of more ’intelligent’ congestion control algori
 thms with added capability of knowing the identity of aggressor protocols 
 against TCP\, and subsequently using this additional information for rate 
 control. \n\n
LOCATION:SS03\, William Gates Building
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