DATE: Thursday, April 5, 2001
TIME: Noon - 1 pm
PLACE: Wean Hall 8220

Rajesh Krishna Balan

Carnegie Mellon

TCP HACK: TCP Header Checksum Option to Improve Performance
over Lossy Links

In recent years, wireless networks have become increasingly common and an increasing number of devices are communicating with each other over lossy links. Unfortunately, TCP performs poorly over lossy links as it is unable to differentiate the loss due to packet corruption from that due to congestion. In this paper, we present an extension to TCP which enables TCP to distinguish packet corruption from congestion in lossy environments resulting in improved performance. We refer to this extension as the HeAder ChecKsum option (HACK). We implemented our algorithm in the Linux kernel and performed various tests to determine its effectiveness. Our results have shown that HACK performs substantially better than both SACK and NewReno in cases where burst corruptions are frequent. We also found that HACK can co-exist very nicely with SACK and performs even better with SACK enabled.

Rajesh Krishna Balan did his undergraduate, honours and masters at the School of Computing, National University of Singapore. The work being presented is part of his Masters thesis and is being presented at Infocom 2001 (April 24th-28th 2001 at Achorage, Alaska).

Rajesh joined CMU as a Ph.D. student in CSD in August 2000. He is currently being advised by Prof. M. Satyanarayanan and his current research interests are:

  • the redesign of Odyssey
  • porting of Coda/Odyssey to the Compaq iPAQ to use as a testbed for testing the viability of our ubiquitious computing solutions.
  • the design of a multi-modal network stack (work with Srini Seshan, Srinivasa Aditya and Nikhil Bansal)

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