Liberating TCP: The Free and the Stunts

Abstract:

The Additive-Increase Multiplicative-Decrease (AIMD) mechanism employed by 
TCP hinges on its ability to meet specific bandwidth requirments since it 
has to respond to congestion signals promptly by decreasing its sending 
rate expoenentially. This, in return, imposes strict limitations on the 
achievable bandwidth required by a particular application, not just in terms 
of the number of congestion signals it receives, but also on the timing of 
when they do occur. To that end, this paper presents a new architecture, 
whereby a set of TCP connections (we refer to them as stunts connections) 
sacrifice their performance on behalf of another TCP conenction (we refer to 
it as the free connection) by observing this congestion signal and reacting 
to it instead of the free connection. With this architecure in place, 
applications can now request specific bandwidth requirments and have the 
free connection adjust which congestion signals it reacts to it and which to 
delegate to the stunt connections in order to meet those specific bandwidth 
requirments.