challenges in Internet simulation & analysis mathematical frameworks to find structure/patterns in traffic a la scott's encouragement to `formalize some of what we (and providers) know' macroscopic as well as microscopic theory of joing spatial/temporal locality spectroscopy, tomography ietf/ippm has been trying for a few years, but without dedicated funding source modeling (for realistic inputs into simulations, models) extract a set of source models from an aggregate trace feature extraction problem 10,000 gnutella port numbers are not 10,000 flows ultimate goal: augment libraries of source level models w generation of own calibrate models by evaluating their power for prediction empirically validated simulation of a significant aspect of the Internet already much work in large-scale simulations, but no recognized empirically validated simulation of any signficant piece of the Internet. requires cooperation from providers and vendors to get default and configured parameters of OSes and algorithms. NSF should shepard/foster this cooperation (note: large scale means in size as well as # of protocols)