An architectural approach that meets high bandwidth requirements by introducing a communication architecture based on lightpaths, optical transmission paths in the network, is introduced. Since lightpaths form the building block of the proposed architecture, its performance hinges on their efficient establishment and management. It is shown that although the problem of optimally establishing lightpaths is NP-complete, simple heuristics provide near optimal substitutes for several of the basic problems motivated by a lightpath-based architecture.>

The problem addressed arose from the evolution of broadband applications and the design of networks that service them. An emerging approach optimizing the transport mechanism in these networks is based on the establishment of virtual topologies. The problem of determining the set of physical links for each virtual link routing is studied. These sets are chosen so as to minimize delay and maximum physical link congestion. A lower bound on the problem and a heuristic solution that achieves near-optimal results when compared with the bound are developed.>

A performance study of two onboard stored, baseband switched, TDMA satellites interconnected through intersatellite links is presented. The uplinks are operated under the slotted ALOHA policy, while the downlinks and intersatellite links are operated using TDM policy. Each satellite has a finite buffer capacity for successful packets arriving, on the uplinks and on the intersatellite links. The authors introduce an approximate analytical model that determines the satellite cluster performance in terms of mean delay, throughput, and overflow probability. The system performance is obtained as a function of the system load, traffic distribution, number of uplinks, number of buffers, number of Earth zones, number of transponders at each satellite, and the intersatellite link capacity. The analytical results were within the confidence intervals of the simulation results obtained with 99% confidence level. Using this model, the system designer can obtain the minimal system configuration for a required system performance.>

An inherent problem of conventional point-to-point wide area network (WAN) architectures is that they cannot translate optical transmission bandwidth into comparable user-available throughput due to the limiting electronic processing speed of the switching nodes. A solution to wavelength division multiplexing (WDM)-based WAN networks that addresses this limitation is presented. The proposed lightpath architecture trades the ample bandwidth obtained by using multiple wavelengths for a reduction in the number of processing stages and a simplification of each switching stage, leading to substantially increased throughput. The principle of the lightpath architecture is the construction and use of a virtual topology network in the wavelength domain, embedded in the original network. A study is made of the embedding of virtual networks whose topologies are regular, using algorithms which provide bounds on the number of wavelengths, switch sizes, and average number of switching stages per packet transmission.>

Emerging applications require a substantially higher bandwidth than the one offered by current networks. The authors propose a novel architectural approach that meets the high bandwidth requirements by introducing a communication architecture based on lightpaths, which are purely optical transmission paths in the network. Since lightpaths form the building block of the proposed architecture, its performance hinges on their efficient establishment and management. The authors shown that although the problem of optimally establishing lightpaths is NP-complete, distributed heuristics provide near-optimal solutions for several of the basic problems presented by the lightpath architecture.>

Emerging high speed networks are using optical fibers employing time division synchronous communication. In these systems the use of optical switching is strongly advocated due to the bottleneck created by store and forward in electronic components. Switching solutions geared toward optical systems have been proposed so far only for packet switching networks.