DATE: Thursday, April 5, 2001 
     TIME: Noon - 1 pm 
     PLACE: Wean Hall 8220 
 SPEAKER: 
      Rajesh Krishna Balan 
    Carnegie Mellon 
 TITLE: 
     TCP HACK: TCP Header Checksum Option to
      Improve Performance 
      over Lossy Links  
 ABSTRACT: 
    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. 
 BIO: 
    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)
SDI / LCS Seminar Questions?
    Karen Lindenfelser, 86716, or visit www.pdl.cmu.edu/SDI/ 
