A study on layer correlation effects through a multilayer network optimization problem

Multilayer network design has received significant attention over the years. Despite this, the explicit modeling of three-layer networks such as IP/MPLS-over-OTN-over-DWDM in which the OTN layer is specifically considered has not been addressed before. In this paper, we present an optimization model for network planning of such multilayer networks that consider the OTN layer as a distinct layer with its unique technological sublayer constraints. More importantly, we present a comprehensive study to quantify the interrelationship between layers through change in unit cost of elements and capacity modularity, coupled with network demand. Focusing on the interrelation between the IP/MPLS and OTN layers, we present a detailed numeric study that considers various cost parameter values of each layer in the network and analyzes their impacts on individual layers and overall network cost.