stated: OTN can be thought of as the freight containers that carry Ethernet, IP, and SONET optical traffic together. The OTN standard was created for the efficient operation of providers' multi-protocol metropolitan and global optical networks using interoperable equipment. The standard provides a framework for programming, monitoring, and transmitting the growing amounts of IP packet, Gigabit Ethernet, video, and MPLS (Multi- Protocol Label Service) traffic while preserving its capability to carry legacy traffic on optical networks. All www.TechnicalPDF.com of the services-1 and 10 Gigabit Ethernet, SONET, and video can be on the same line card and are software programmable. It does SO by specifying the encapsulation of legacy SONET/Synchronous Digital Hierarchy (SDH) traffic into OTN frames and its overhead information for addressing and billing on fiber-optic cabling. OTN, which can scale to 400Gbps and Terabit capacities, overcomes SONET's 40 Gigabit per second capacity. See Table 4-2 in the "Appendix" for information on SONET speeds. OTN equipment has optional modules for connecting to Dense Wavelength Division Multiplexing (DWDM) as well as Reconfigurable Optical Add/Drop Multiplexing (ROADM) SO that individual wavelengths can be seamlessly added and dropped off at, for example, carriers' POPs. Both SONET/SDH and IP traffic can be carried on the same wavelength. (DWDM gear splits each pair of fiber cabling into multiple paths called wavelengths.) Manufacturers that offer OTN gear include Calix, Ciena, Cisco, Fujitsu, Infinera, and Nokia. Today's networks are required to carry a mix of the more efficient gigabit Ethernet as well as traffic using the older SONET and MPLS protocols. Optical Transport Network is an important protocol for transporting both digital Internet Protocol (IP) signals as well older synchronous traffic in a single stream. Gigabit Ethernet supports the massive increases in traffic due mainly to traffic generated by enterprises and consumers accessing the cloud, by consumers streaming TV 