Toward alternative high-speed network concepts: the SWIFTarchitecture

An approach to communication architectures for high-speed networks which provides efficient, adaptive communication for any traffic distribution is presented. It is based on a concept of dynamic sharing of communication resources which is obtained from the following three-tier SWIFT architecture. At the physical layer the high-speed communication system is based on the use of several lower speed channels or frequencies. At the data link layer, driven by hardware simplicity considerations, the SWIFT architecture uses a fixed time-slotted allocation of subchannels, in which each node is required to transmit or receive over only a single, predetermined, subchannel at a time. To provide adaptive channel access control, while preserving the data link hardware simplicity, a network layer is added. This layer introduces multihop adaptive channel (frequency) routing on the inherently broadcast communication medium. The routing concept provides dynamic sharing of communication channels and buffers, leading to a fully distributed adaptive bandwidth control. An analytic model for analyzing the performance of the multilayered architecture is developed. It shows that for homogeneous or heterogeneous traffic requirements the approach provides throughput/delay performance superior to that found in existing communication systems     

An evaluation of distributed wavelength provisioning in WDM optical networks with sparse wavelength conversion

Distributed wavelength provisioning is becoming one of the most important technologies for supporting next-generation optical networks. This paper describes the evaluation of the performance of distributed wavelength provisioning in wavelength-division-multiplexing (WDM) optical networks with sparse wavelength conversion (i.e., where wavelength conversion is available at only a subset of network nodes). Using the well-known destination-initiated reservation method as a case study, a highly accurate analytical model supported by comprehensive simulation validation is proposed. Both analytical and simulation results show that, in optical networks with distributed wavelength provisioning, sparse wavelength conversion still helps to significantly lower the connection-blocking probabilities. However, unlike that in centralized wavelength provisioning, sparse wavelength conversion may not easily achieve nearly the same performance as that of full wavelength conversion, especially under light traffic loads. This paper evaluates how the potential contribution of sparse wavelength conversion depends on different factors, such as the number of wavelength converters, the number of wavelength channels per fiber, the burstiness of traffic loads, and the network size, and discusses the influence of the signaling scheme.     

Heterogeneous personal communications services: integration of PCSsystems

Personal communications services (PCS) are being introduced to offer ubiquitous communication. In its first phase PCS consists of a plethora of systems that address cellular, vehicular, cordless phone, and a variety of other services. The integration of these different systems is referred to as “heterogeneous PCS (HPCS)”. We describe the various PCS systems available and address in detail the issue of PCS systems integration. Key implementation issues for integrating PCS systems are defined and discussed