requency (in nm) Up to 32 Up to 24 Up to 16 Up to 8 usage in various 1560.60 SPARE SPARE SPARE SPARE (D)WDM systems. 1559.79 1558.99 1558.17 1557.38 1556.55 1555.75 1554.04 1554.13 1553.33 1552.52 1551.72 1550.92 1550.12 1549.32 1548.51 1547.72 1541.30 SPARE SPARE SPARE SPARE 1540.58 1539.77 1538.99 1538.18 1537.40 1536.61 1535.82 1535.04 1534.25 1533.47 1532.68 1532.90 1531.12 1530.39 Denotes Supported 1529.55 DWDM Wavelength 1528.77 MOR Plus MOR and MOR Plus Denotes Supported DWDM and Optical Applications Only Applications Add/Drop Wavelength DWDM Wavelength Plan for NDSF and NZ-DSF Fiber Dense Wavelength Division Multiplexing (DWDM) Systems Figure 5-29 = Regenerator Open versus proprietary systems. Proprietary Systems Systems International 14 15 18 19 Terminal inexpensive, and readily available transmitters. In contrast to DWDM equipment based on proprietary specifications, systems with open inter- faces provide operators greater freedom to provision services and reduce long-term costs. Proprietary systems, in which SONET/SDH equipment is integrated into the optical multiplexer/demultiplexer unit, are usable for simple point-to-point configurations; however, they require costly additional transmission equipment when deployed in meshed networks. DWDM sys- tems that comply with the ITU channel plan reassure carriers that they can employ equipment from a variety of suppliers, although generally car- riers do not mix equipment from two suppliers on the same ring because of network management (and more generally, Operations, Administration, Maintenance, and Provisioning [OAM&P]) considerations. 5.2.5 Example of High-End DWDM System An example of a high-end DWDM system is Nortel's S/DMS Transport- Node. This system offers high-capacity transport systems operating at either 2.5 Gbps (OC-48) or 10 Gbps (OC-192). Figure 5-30 depicts a schematic view of the product. DWDM arrangements are supported in both OC-48 and OC-192 applications, permitting aggregate span capacities of up Chapter 5 OC-48 and/or OC-192 OC-48 and/or