Projet MEVAL{{\P\n,¸N\geq 1 } is a sequence of standard polling networks, consisting of N nodes attended by V\n mobile servers. When a server arrives at a node i, he serves one of the waiting customers, if any, and then moves to node j with probability p_{ij}\n. Customers arrive according to a Poisson process. Service requirements and switch-over times between nodes are independent exponentially distributed random variables. The behavior of \P\n is analyzed in {\em thermodynamic limit}, i.e when both N and V\n tend to infinity, with $U\egaldef\lim_{N\rightarrow\infty}V\n/N,\
