  We present an analytically tractable model of Internet evolution at the level
of Autonomous Systems (ASs). We call our model the multiclass preferential
attachment (MPA) model. As its name suggests, it is based on preferential
attachment. All of its parameters are measurable from available Internet
topology data. Given the estimated values of these parameters, our analytic
results predict a definitive set of statistics characterizing the AS topology
structure. These statistics are not part of the model formulation. The MPA
model thus closes the "measure-model-validate-predict" loop, and provides
further evidence that preferential attachment is a driving force behind
Internet evolution.
