Guest editorial WDM-based network architectures

R ECENT developments in wavelength division multi-plexing (WDM) technology have led to a tremendous amount of commercial and research interest in WDM-based networks. Until recently, WDM has been used primarily for point-to-point long haul transmission. However, with the emergence of WDM networking components, people are beginning to design and deploy WDM-based networks that take advantage of the flexibility and configurability of these components. For the first time since the emergence of this field, research in this area has found commercial applications. The goal of this issue is to address WDM networking research that can have an impact on the way WDM networks will be designed and deployed over the next several years. In particular, this issue is focused on papers dealing with the design of multihop WDM networks for access, metropolitan, or wide area applications. It is interesting to observe the progress in this field by examining the topics covered by earlier special issues on optical networks. In fact, the progress has been immense! Looking back at the August 1990 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS/IEEE JOURNAL OF LIGHTWAVE TECHNOLOGY special issue on WDM networks, we note that at that time, papers were primarily focused on WDM technologies. Some of the papers in that issue described early experimental testbeds, many dealt with system issues (e.g., cross-talk analysis, nonlinearity issues, etc.), but the majority of the papers described WDM components such as multiplexers, lasers, detectors, etc. A few years later, the June 1996 special issue on optical networks started to address higher layer network issues. A few papers in that issue described ongoing experimental testbeds, and most papers dealt with network layer design issues such as routing and wavelength assignment, benefits of wavelength conversion, and logical topology design. Clearly, progress was made from subsystems to networks, yet mostly at the experimental stage. Obviously, this earlier work paved the way toward the present day boom of optical networks in the commercial marketplace. As optical networks begin to emerge commercially, deployment issues are of critical importance, and largely this is the focus of this issue. In this issue we feature articles that cover topics related to optical network management such as network survivability and fault management as well as network recon-figuration. Also included are papers on topology design issues, such as traffic grooming, logical topology design, and network dimensioning. Finally, included are a few papers on the topic of optical packet switching. …