OTN provides robust transport services that leverage many of the benefits of SONET/SDH such as resiliency and performance monitoring, while adding enhanced multi-rate capabilities in support of packet traffic, plus the transparency required by DWDM networks. OTN is the ideal technology to bridge the gap between next generation IP and legacy time division multiplexing (TDM) networks by acting as a converged transport layer for newer packet-based and existing TDM services. The Cisco NCS 4000 offers a suite of OTN line cards supporting Ethernet, SONET/SDH, and OTN client interfaces with data rates from 1 to 100 gigabits per second.