This paper proposes an architecture for routing Internet protocol (IP) packets directly on optical networks. The use of label switching is assumed in the IP routers, while a new routing architecture is introduced to transport IP packets across an optical backbone network. The architecture is based on a two-tier multiplexing approach, with wavelength division multiplexing (WDM) addressing the number of regional exchanges and time-division switching communicating among the hubs. Such an architecture not only has the advantages of simple network management and high efficiency with low latency; it also is scalable by addition of regional exchanges, hubs, and fibers. Index Terms-Internet protocol (IP) network, optical routing, time-division switching, wavelength division multiplexing (WDM), wide-area network (WAN). Frank Tong received the Ph.D. degree from Columbia University, NY, in 1987 with his thesis work completed at the Massachusetts Institute of Technology (MIT) Lincoln Laboratories, Cambridge. After graduation, he joined IBM Almaden Research Center, where he worked on short wavelength lasers for optical recording. From 1989 to 1996, he worked on optical networking technologies under P. Green at IBM T.