Modelling and Stability of Fast TCP [chapter]

Jiantao Wang, David X. Wei, Joon-Young Choi, Steven H. Low
2007 IMA Volumes in Mathematics and its Applications  
We discuss the modelling of FAST TCP and prove four stability results. Using the traditional continuous-time flow model, we prove, for general networks, that FAST TCP is globally asymptotically stable when there is no feedback delay and that it is locally asymptotically stable in the presence of feedback delay provided a local stability condition is satisfied. We present an experiment on an emulated network in which the local stability condition is violated. While the theory predicts
more » ... , the experiment shows otherwise. We believe this is because the continuous-time model ignores the stabilizing effect of self-clocking. Using a discrete-time model that captures this effect, we show that FAST TCP is locally asymptotically stable for general networks if all flows have the same feedback delay, no matter how large the delay is. We also prove global asymptotic stability for a single bottleneck link in the absence of feedback delay. The techniques developed here are new and applicable to other protocols.
doi:10.1007/978-0-387-48945-2_14 fatcat:re7hvxl3wfgn5ckk5eue2y3lci