The 2-layered network design problem

We present here the problem of designing a network that is built on two
layers. An example of telecom application is the design of a virtual 
network (IP) built on a sparse physical network (WDM). We propose a 
mathematical formulation without any flow variable or path variable, 
based on polyhedral approach. We give numerical results for two-layered 
network instances obtained with a global method giving optimal solutions 
for different cost configurations.