Various MPLS-based IP over WDM integration techniques are considered in this article. In particular, this includes the circuit-switching MP/spl lambda/S framework for providing logical IP-layer topologies over optical lightpath routing networks. Additionally, an optical code label switching technique for photonic packet switching and its application to MPLS is also introduced, termed OC-MPLS. The related advantages and challenges of both of these approaches are discussed, and various future research issues are addressed.