Of mice and models

Modeling mice in an effective and scalable manner is one of the main challenges in the performance evaluation of IP networks. Mice is the name that has become customary to identify short-lived TCP connections, that form the vast majority of packet flows over the Internet. On the contrary, long-lived TCP flows, that are far less numerous, but comprise many more packets, are often called elephants. Fluid models were recently proved to be a promising effective and scalable approach to investigate the dynamics of IP networks loaded by elephants. In this paper we extend fluid models in such a way that IP networks loaded by traffic mixes comprising both mice and elephants can be studied. We then show that the newly proposed class of fluid models is quite effective in the analysis of networks loaded by mice only, since this traffic is much more critical than a mix of mice and elephants.