IP over reconfigurable optical network architectures have been extensively discussed within the research literature over the past few years. However, although reconfigurable optical networks have been deployed and signaling protocols between IP routers and optical networks have been standardized, large IP backbones are typically deployed usimg the reconfigurable optical networks. One of the most important criteria in determining whether an IP backbone should be carried over a reconfigurable optical network is economic viability - which necessitates a detailed, accurate economic study of IP backbone over reconfigurable optical network architectures. In this paper, we analyze and explore four IP over optical network architectures for a typical large ISP backbone. In contrast with other published claims, our results suggest that an IP over opaque re-configurable optical network architecture is not economically attractive with current equipment and IP backbone network design requirements. However, for ISPs also carrying large volumes of transport network private line services, our proposed integrated IP over re-configurable optical network architecture may provide an attractive alternative for providing rapid, cost effective failure recovery.