A convergence of technology innovations is giving rise to a new concept of routed optical networking in which Layer 3 becomes the switching layer across a DWDM transport layer. The key advances are the commercialization of 400Gbps pluggable coherent optics, the emergence of multi-terabit network processing units (NPUs) for routers, and continuing advances in telemetry and software automation for IP networks. While sharing some of the same heritage, the new routed optical network is not your father s IP over DWDM.
Defined as the physical integration of DWDM optics into a router, the concept of IP over DWDM (or IPoDWDM) has been around for decades with continuing interest from operators that never translated into large-scale deployments. Explaining the appeal is simple: placing DWDM optics directly into the router eliminates the transponder shelf and optics between routers and DWDM systems a capex win.