An optimization model of protocol stack and hetergeneous protocols

Tuesday, June 28, 2005 - 2:00pm - 3:00pm
EE/CS 3-180
Steven Low (California Institute of Technology)
Can we integrate the various protocol layers into a single coherent theory by regarding them as carrying out an asynchronous distributed primal-dual computation over the network to implicitly solve a global optimization problem? Different layers iterate on different subsets of the decision variables using local information to achieve individual optimalities, but taken together, these local algorithms attempt to achieve a global objective. Such a theory will expose the interconnection between protocol layers and can be used to study rigorously the performance tradeoff in protocol layering as different ways to distribute a centralized computation. We describe some preliminary work on cross layer interactions involving HTTP, TCP, IP, MAC, and scheduling. All of these instances can be integrated within a utility maximization model. We present equilibrium and stability properties of networks shared by TCP sources that react to different pricing signals where the current utlity maximization model breaks down.