Overlay vs. integrated traffic engineering for IP/WDM networks

In this paper we present two traffic-engineering approaches, overlay and integrated, for IP over reconfigurable WDM networks, The overlay approach presents a layered model between IP and WDM, in which IP layer requests transport services from WDM layer. Traffic engineering is performed in each layer, where the two layers communicate through defined interfaces. The integrated approach emulates a peer-to-peer model between IP/WDM nodes, each of which is capable of IP traffic engineering control, and makes physical resource allocation decisions based on the locally maintained IP/WDM network state information. We outline a functional framework for traffic engineering applicable to either approach, and describe the corresponding software implementation architecture for these approaches.