IP/MPLS over OTN over DWDM multilayer networks: optimization models, algorithms, and analyses

Abstract

Over the past decade, multilayer network design has received significant attention in the scientific literature. However, the explicit modeling of IP/MPLS over OTN over DWDM in which the OTN layer is specifically considered has not been addressed before. This multilayer network architecture has been identified as promising that bridges integration and interaction between the IP and optical layers. In this dissertation, we consider four related problems. First, we present an integrated capacity network optimization model for the operational planning of such multilayer networks. The model considers the OTN layer as a distinct layer with its unique technological ODU sublayer constraints. Secondly, we present a design model to investigate the correlation effects of the IP and OTN layers when the physical DWDM layer capacity is a given constant. We also develop a heuristic algorithm to solve the models for large networks. We provide comprehensive numeric studies that consider various cost parameter values of each layer in the network and analyze the impact of varying the values on network layers and overall network cost. We have observed the significant impact of the IP/MPLS capacity module on each layer and the entire network. Generally, when this parameter size is above the average demand in the network, it leads to the best overall network design. Thirdly, we consider the problem of optimizing node capacity in this architecture as our design goal, since routers with more capacity and complex structure consume significant power. We present an explicit networking optimization model that aims to minimize the total capacity at the LSRs and the OXCs. Our assessment shows that the different weight ratios of LSR to OXC nodes do not generally affect the overall required capacity of each layer. However, the weight ratios influence differently required node capacity at nodes in each layer. Finally, we factor in the survivability of the multilayer network by considering a suitable protection mechanism for each network layer. We provide a phase-based heuristic approach, study and analysis. We have also examined the network performance from cost vs. protection capacity perspectives while varying the size of the IP/MPLS capacity module.