long with inexpensive passive components for CWDM using 8, 12, or 16 channels make this approach a viable solution. CWDM technology can be deployed to take advantage of this evolving metro oppor- tunity and deliver significant cost savings to local area networks (LANs), storage area networks (SANs), and metro access broadband optical carrier networks. End users, in turn, can access, accumulate, and disseminate information over these networks more cost-effectively. As noted, however, one of the critical issues yet to be fully addressed is Operations, Adminis- tration, Maintenance, and Provisioning (OAM&P) support. Unfortunately, CWDM technology has not yet developed to the point where a well- recognized architecture for standard deployment is available and a set of operational disciplines in the OAM&P context (supported by feature-rich OSSs) exists. Hence, the de facto alternative to CWDM-based metropolitan systems at this time is next-generation SONET. Chapter 6 One way that CWDM and DWDM differ noticeably is in the spacing between adjacent wavelengths. DWDM packs many channels into a small usable spectrum, spacing them one to two nanometers (nm) apart. DWDM systems support a high channel count, but also require expensive cooling equipment and independent lasers and modulators to ensure that adjacent channels do not interfere. CWDM systems, on the other hand, use 10- to 25- nm spacings with 1,310- or 850-nm lasers that drift less than 0.1 nm/ centigrade (C). This low drift eliminates the need for cooling equipment, which, in turn, reduces the total system cost. As a result, CWDM systems support less total bandwidth than DWDM systems; however, with 8 to 16 channels, each operating between 155 Mbps and 2.5 Gbps (and soon 10 Gbps), these systems can deliver bandwidths ranging from 1 Gbps to over 100 Gbps. Figure 6-2 plots the general wavelengths used by various WDM technologies. 2 Typical systems support 8 wavelengths, data rates up to 2.5 Gbps per wavelength, and distances up to 50 km. CWDM uses lasers with a wide 