Why We Don't Know How To Simulate The Internet

Vern Paxson
Network Research Group
Lawrence Berkeley National Laboratory
University of California, Berkeley CA 94720
e-mail: vern@ee.lbl.gov

Sally Floyd
Network Research Group
Lawrence Berkeley National Laboratory
University of California, Berkeley CA 94720
e-mail: floyd@ee.lbl.gov

Abstract:

Simulating how the global Internet data network behaves is an immensely challenging undertaking, because of the network's great heterogeneity and rapid change. The heterogeneity ranges from the individual links that carry the network's traffic, to the protocols that interoperate over the links, to the ``mix'' of different applications used at a site and the levels of congestion (load) seen on different links. We discuss two key strategies for developing meaningful simulations in the face of these difficulties: searching for invariants and judiciously exploring the simulation parameter space. We finish with a look at a collaborative effort to build a common simulation environment for conducting Internet studies.

Link to paper.