Fast restoration of ATM networks

Asynchronous transfer mode (ATM) is now well recognized as the fundamental switching and multiplexing technique for future broadband ISDN. As these networks will be increasingly relied upon for providing a multitude of integrated voice, data, and video services, network reliability is a key concern. There are several intrinsic features of ATM networks that could potentially be exploited to provide improved restoration techniques, beyond those established for synchronous transfer mode (STM) networks, such as digital cross-connect restoration or self-healing rings. These features include ATM cell level error detection, inherent rate adaptation and nonhierarchical multiplexing. The authors explore the use of these features in developing fast restoration strategies for ATM networks. In particular, they address: (1) ATM error detection capabilities for enhanced failure detection, (2) network rerouting strategies, (3) spare capacity allocation, and (4) network control architecture and related implementation aspects. Their findings suggest that fast network span failure detection and bandwidth-efficient rerouting capabilities can be combined to develop restoration strategies for ATM networks with significantly greater performance-cost ratios when compared to existing STM network restoration strategies     

Comparison of Room Temperature and Cryo-Deformation Effects on Mechanical Properties and Microstructure of Copper

The objective of this work is to study the effect of room temperature (RT) and liquid nitrogen temperature (LNT) rolling on mechanical properties of the pure copper. For the same percentage deformation, LNT samples show a significant increase in tensile strength and hardness value compared to RT samples. Microstructural investigation shows a large misorientation change between RT and LNT samples when we use grain orientation spread (GOS) as a measure of microstructural change. The mechanical property and microstructural changes are correlated with calorimetry experiments. We also present some preliminary results from our work on wire drawing at RT and LNT.     

Broadband network infrastructure of the future: roles of networkdesign tools in technology deployment strategies

The rapid pace of technology introduction in the network infrastructure and services offered on this infrastructure are creating new challenges for telecommunication product and network planners. In particular, a multitude of choices, the unpredictability of future technologies and traffic, the need to operate heterogeneous networks, and the speed of change create a need for a set of tools which allow quantitative evaluation of alternatives quickly in early phases of decision making while allowing the same tools to migrate to more elaborate deployment help during the later stages. We have begun an effort to create such a set of tools under the umbrella of integrated network design tools (INDT). In this article, we describe key challenges and approaches used in INDT to meet these challenges. We also discuss the algorithmic and software architecture of INDT, and illustrate its use via examples from transport infrastructure evolution. Finally, we describe the migration path of INDT to move from early decision help to later deployment support tools. Specific topics discussed include: plesiosynchronous digital hierarchy, SONET/SDH systems, ATM, network topologies, traffic types and routing     

A note on weight-based load balancing on SONET rings

In a recent paper, Cosares and Saniee [2] introduced the problem of balancing loads on SONET [1] rings. This note gives a counterexample to one of their results and then states the correct result.     

Stochastic balancing and approximation-stability and minimality

A new method of stochastic model reduction has recently been introduced by Desai et al. [1], [2]. The stability of the reduced order model has not previously, been considered. In this paper, we show that the stability of the reduced order model follows directly from the results of Pernebo and Silverman [3]. It is also shown that the reduced order model is minimal, in the controllability/observability sense. The relevance of this notion of minimality to stochastic minimality is made clear.