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                   B O S T O N   U N I V E R S I T Y
                      Computer Science Department
                          C O L L O Q U I U M
                      Friday, January 18, 3:00 PM 
                       (Coffee served at 2:45PM)
                         Seminar Room / MCS 135

			
      Transport-level Protocol Coordination for Cluster-to-Cluster
	                      Applications

			      
                            Ketan Mayer-Patel 
                      Department of Computer Science 
                             UNC-Chapel Hill

		                 Abstract


We identify an emerging and important application class comprised of a 
set of processes on a cluster of devices communicating to a remote set 
of processes on another cluster of devices across a common intermediary 
Internet path. We call these applications cluster-to-cluster applications,
or C-to-C applications. The networking requirements of C-to-C applications
present unique challenges.  Because the application involves communication 
between clusters of devices, very few streams will share a complete 
end-to-end path. At the same time, network performance needs to be measured 
globally across all streams for the application to employ interstream adaptation 
strategies.  These strategies are important for the application to achieve its 
global objectives while at the same time realizing an aggregate flow behavior 
that is congestion controlled and responsive. We propose a mechanism called 
the Coordination Protocol (CP) to provide this ability. In particular, CP makes
fine-grained measurements of current network conditions across all flows 
associated with the C-to-C application and provides aggregate loss and available
bandwidth information using an equation-based congestion control algorithm. 
One particularly interesting feature is that CP enables the aggregate bundle 
of flows of a C-to-CS application to respond to congestion in a manner that 
is on par with the behavior of k TCP flows, where k is greater than 1 and unrelated
to the actual number of flows in the aggregate bundle.


Host: John Byers
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