This paper presents a general closed-form analysis of the time-blocking probability in time-driven switching networks. Time-blocking occurs when transmission resources are available in both input and output, but there is no schedule, i.e., input and output resources are outside a pre-defined maximum scheduling delay that is allowed between them. This situation may happen in architectures based on pipeline forwarding of packets. The main constraints affecting the schedulability of resources are the load and the maximum scheduling delay. The analysis yields the exact blocking probabilities for all possible scheduling delays and under all load conditions for a node in isolation, as well as initial results for a network of nodes.

Fractional lambda switching (FlambdaS) is a novel approach for traffic management over all-optical networks with sub-wavelength provisioning capability. The unique characteristic of FlambdaS is the utilization of UTC (coordinated universal time) for switching with minimum or no buffers. Several central research issues are still open in FlambdaS and need to be formally defined and analyzed. In this paper, we introduce three novel switch designs that are based on the use of tunable lasers (which can be replaced in the future with wavelength converters). First, the paper presents analytical results of scheduling feasibility, which measures the total number of possible different schedules for each switch design. Then it is shown that the architecture with the highest scheduling feasibility is strictly non blocking in the space domain. Next, the paper provides a closed form analysis of the blocking probability in the time domain, which is applicable for any strictly non-space blocking switch, using combinatorics. In addition, the paper provides measures of the switching hardware complexity, which, for the strictly non-blocking architecture, has the same switching complexity as Clos interconnection network, i.e., O(N'radic(N')) where N' is the number of optical channels.

In order to achieve ultra scalable IP packet switching it is essential to minimize "stopping" of the serial bit streams. In our recent experimental work we demonstrated how this can be achieved with an ultra-scalable switching architecture reaching multi-terabits per second (10-100 Tb/s) in a single chassis. The implemented testbed uses only off-the-shelf optical and electronic components. The scalability of this architecture is the direct outcome of how global time (i.e., UTC - coordinated universal time) and pipeline forwarding are utilized. The paper presents the design of a prototype switch and experimental activity with it.

Future Internet traffic will be dominated by on-demand streaming media flows, such as IPTV, 3D/HD video, gaming, virtual reality, and many more. Consequently, future network architectures will need to implementscalable IP packet switchingcapable of offeringpredictable performancesto such applications. Our recent experimental work demonstrated how an IP network can be implemented without "stopping" the serial bit streams. The deployed switch is very simple, scalable to 10-100 terabits per second in a single chassis, and suitable for all optical implementation. The implemented testbed uses only off-the-shelf optical and electronic components and was completed in 9-month.

As data traffic on the Internet continues to grow exponentially, there is a real need to solve the switch bottleneck by developing ultra-scalable switching fabrics and their control. Although in recent years there have been a lot of efforts to solve the switching fabric scalability problem, in the optical domain, the proposed solutions have been (very) expensive, (very) complex and (much) larger than electronic switching fabric alternatives. In order to increase scalability a coordinated universal time (UTC) based time-driven switching (TDS) is proposed. This novel low-complexity switching architecture capitalizes on the ubiquitous of UTC from GPS and Galileo. This work focuses on UTC-based FPGA (field programmable gate- array) controller that was implemented for controlling the TDS switch prototype at the University of Trento, Italy. The switch controller facilitate dynamic configuration of ultra scalable switch. The prototype is implemented using off-the-shelf components. TDS architecture is especially suitable to support high capacity streaming media applications over the Internet.

Fractional Lambda Switching (FλS) is a novel proposal for the management of all-optical networks with sub-wavelength provisioning capability. The unique characteristic of FλS is the utilization of the UTC (coordinated universal time) for alignment and switching. Several central research issues are still open in FλS and need to be formally defined and analyzed. Within the scope of this paper, we introduce three novel switch architecture designs that are based on the use of tunable lasers. As an important goal, we introduce the notion “scheduling feasibility” that measure the number of possible different scheduling between an input and output time-frames.