Metro transport networks must support numerous service demands: transmission of low-rate 10/100BASE-T and OC-3/STM-1 signals; higher-rate OC-12/STM-4, Gigabit Ethernet, OC-48/STM-16 signals; video signals such as standard-definition Serial Data Input (SDI) and high-definition SDI (HD-SDI); optical-transport-unit-1 (OTU-1) services; and first-generation (1G), 2G, 4G, and 8G Fibre Channel services. The flexibility to support multiple rates and aggregate them over a dense wavelength-division multiplexing (DWDM) interface using OTN technology brings huge savings in operating and management costs.