The International Computer Science Institute
is pleased to present a talk:

"A(nother) Technique for Improving Transport Protocol Performance in Lossy Networks"

Mark Allman ICSI
mallman icsi.berkeley.edu

Wednesday, April 28, 2004 ICSI, Conference Room 6A 12:30 pm

One of the lingering problems with employing standard Internet transport protocols (e.g., TCP) in wireless networks is a loss of performance due to standard congestion control techniques. In traditional wireline networks packet loss is nearly always caused by network congestion (resource contention). Therefore, congestion control algorithms in transport protocols have been built around the assumption that packet loss indicates congestion. That is, when packet loss occurs the transport protocol's sending rate is reduced in an effort to alleviate the congestion. However, in wireless environments non-negligible amounts of packet corruption also cause packet losses --- to the detriment of performance. In this talk, we discuss a new mitigation to this problem based on observations from the analytical model of TCP's congestion control algorithms. The scheme we evaluate requires assistance from routers along the path in the form of reports about the aggregate loss rate due tocorruption. We show simulations that indicate our techniques are promising. However, we also discuss the significant security and deployment challenges that must be met before our schemes could be used in real networks. Finally, we will touch on the broader issues of increasing the transport protocol's vision into the dynamics of the network path.