Benefits from 2-layer traffic engineering for IP/MPLS networks

Multi-layer aspects of network and traffic engineering have been extensively studied from various perspectives and potential benefits for savings in capital and operational expenditures have been demonstrated. Integrated approaches for traffic engineering and network planning come closer towards a practical implementation with the progress in standardization of protocols like generalized multiprotocol label switching (GMPLS). In this paper we consider the aspect of optimizing the routing of IP links in the underlying transport layer in order to improve the failure scenarios in the IP/MPLS layer. The goal is to minimize worst case network utilizations and avoid potential overload situations. We propose an approximation algorithm to solve the general 2-layer optimization problem in large realistic network scenarios and conduct a case study to validate our approach. On the one hand we address a rather small aspect of multi-layer network optimization here but on the other hand we identify benefits that allow for a short-term implementation.