While all-optical networking had its origins in the research community a quarter of a century ago, the realization of the vision has not had a straight trajectory. The original goal of the all-optical network was based on keeping the data signals entirely in the optical domain from source to destination to eliminate the so-called electronic bottleneck, and to allow arbitrary signal formats, bitrates, and protocols to be transported. The latter property is referred to as transparency. When all-optical networks were finally commercialized around the turn of the century, however, a modified reality emerged; the quest for transparency was replaced by the more pragmatic objective of reducing the network cost and energy consumption. Moreover, especially for networks of large geographical extent, electronics were still present at some (relatively few) points along the data path, for signal regeneration and traffic grooming. This modified vision captures the state of today's networks, though terms like all-optical and transparent are still used to describe this technology. However, continued advancements are bringing back some aspects of the original transparency vision. In this paper, we review the evolution of all-optical networking, from the early vision to its present vibrant state, which was made possible by great advances in optical transmission and all-optical switching technologies. We describe the numerous benefits afforded by the technology, and its relative merits and drawbacks compared to competing technologies, sometimes referred to as opaque. We also discuss the remaining challenges and future directions of all-optical networking. While all-optical solutions permeate today's access, metro, and core networks, this paper focuses on the core.

With the expected explosive growth in data traffic, the required processing demands at network nodes, e.g., in routers, will likely present a significant bottleneck. Optical bypass potentially alleviates this bottleneck by allowing a wavelength to bypass a node if it contains no traffic that needs to be processed there. We explore the value of optical bypass in gigabit networks by measuring the fractional decrease in required router size one can expect. We consider both ring and mesh topologies, and both uniform and distance-dependent traffic. We show that the reduction in router size can be very significant, with the fractional savings increasing as the size of the network increases and the amount of traffic increases, indicating that this technique will scale well in future networks.

Presents a logical approach to designing an effective and efficient error detection scheme for ATM. The authors specifically look at providing error protection for the class C service of ATM, which is a connection oriented, variable bit rate service, with no required timing between source and destination. The resulting scheme is similar to the scheme proposed by the CCITT in AAL 5. The authors propose to add a 34 bit CRC to each frame. Their proposal also includes a modification of the mechanism for preventing misdirected cells that is used at the ATM layer.>