This book provides a broad overview of IP over WDM technologies, as seen by a group of experts participating in the e-Photon/ONeC and BONE Networks of Excellence funded within the VIth and VIIth Research Framework Programmes (FP6 and FP7) of the European Union. Both Networks of Excellence are aimed at the integration of research teams active on optical networks at a pan-European level, with the creation of virtual centers of excellence in optical networks, te- nologies, and services. The working groups on optical core networks gathered about a 100 researchers from more than 20 universities...