Moshe Zukerman

Performance analyses of optical burst-switching networks

This paper provides a scalable framework for analysis and performance evaluation of optical burst-switching (OBS) networks. In particular, a new reduced load fixed point approximation model to evaluate blocking probabilities in OBS networks is introduced. The model is versatile enough to cover known OBS reservation policies such as just-enough-time, just-in-time, burst segmentation, and route-dependent priorities. The accuracy of the model is confirmed by simulation and the various policies are compared.

Broadband traffic modeling: simple solutions to hard problems

A much clearer picture of the progress toward an integrated high-speed multiservice network is now emerging. Such networks were anticipated over 20 years ago, at a time when packet switching was just another way to transmit data. Now the technology is so mature that media barons are organizing their investments in order to take advantage of its profitability. Many of the technical problems are now solved, and the fundamental protocols required for these networks are sufficiently well-defined to support a rapidly expanding industry. However, consensus on how to talk about the statistics of the data transmitted around these networks has not been readily forthcoming. Nevertheless, there now exists a family of models with sufficient richness to describe real traffic fairly well, which can be parameterized conveniently, and which degenerates to a readily analyzable Gaussian model in the situation of very large networks. This analysis leads to important architectural conclusions which accord with common sense, in particular the conclusion that integrated networks of the future should be able to provide better and better service with efficiency tending toward perfection. This is a rather happy conclusion which thoroughly confirms the current rapid drive toward an all-encompassing integrated multiservice network. Rather than the increase in traffic and diversity of service types leading to greater and greater complexity, it seems that the flow of traffic in our networks may become steadily more manageable.

Energy-Efficient Base-Stations Sleep-Mode Techniques in Green Cellular Networks: A Survey

Due to global climate change as well as economic concern of network operators, energy consumption of the infrastructure of cellular networks, or “Green Cellular Networking,” has become a popular research topic. While energy saving can be achieved by adopting renewable energy resources or improving design of certain hardware (e.g., power amplifier) to make it more energy-efficient, the cost of purchasing, replacing, and installing new equipment (including manpower, transportation, disruption to normal operation, as well as associated energy and direct cost) is often prohibitive. By comparison, approaches that work on the operating protocols of the system do not require changes to current network architecture, making them far less costly and easier for testing and implementation. In this survey, we first present facts and figures that highlight the importance of green mobile networking and then review existing green cellular networking research with particular focus on techniques that incorporate the concept of the “sleep mode” in base stations. It takes advantage of changing traffic patterns on daily or weekly basis and selectively switches some lightly loaded base stations to low energy consumption modes. As base stations are responsible for the large amount of energy consumed in cellular networks, these approaches have the potential to save a significant amount of energy, as shown in various studies. However, it is noticed that certain simplifying assumptions made in the published papers introduce inaccuracies. This review will discuss these assumptions, particularly, an assumption that ignores the effect of traffic-load-dependent factors on energy consumption. We show here that considering this effect may lead to noticeably lower benefit than in models that ignore this effect. Finally, potential future research directions are discussed.

Blocking probability for priority classes in optical burst switching networks

This letter proposes a method to strictly prioritize switching access in just-enough-time (JET)-based optical burst switching networks. A queueing model is developed by which the blocking probability for each traffic class can be analytically evaluated. The analytical results are validated by simulations.

PD-RED: to improve the performance of RED

We propose a new active queue management (AQM) scheme to improve the performance of the well-known random early detection (RED) AQM. The new AQM is based on the proportional derivative (PD) control principle, and we call it PD-RED. In PD-RED we introduce minimal changes to RED. We demonstrate the improvement in performance of PD-RED over adaptive RED AQM by simulations.

An adaptive connection admission control scheme for ATM networks

A new adaptive connection admission control scheme is proposed. The aggregate statistics of all calls in progress are continuously measured and new calls are considered as CBR at their peak during certain warming up period. The main features of our proposed CAC scheme are (1) an adaptive mechanism which updates the warming up period based on the traffic conditions, (2) an accurate mechanism to predict cell loss, and (3) a simple and conservative way to consider call departures. We demonstrate by simulation that the scheme is more efficient than several other schemes.

Connectivity, coverage and placement in wireless sensor networks

Wireless communication between sensors allows the formation of flexible sensor networks, which can be deployed rapidly over wide or inaccessible areas. However, the need to gather data from all sensors in the network imposes constraints on the distances between sensors. This survey describes the state of the art in techniques for determining the minimum density and optimal locations of relay nodes and ordinary sensors to ensure connectivity, subject to various degrees of uncertainty in the locations of the nodes.

Internet traffic modeling and future technology implications

This paper presents the Poisson Pareto burst process (PPBP) as a simple but accurate model for Internet traffic. It presents formulae relating the parameters of the PPBP to measurable traffic statistics, and describes a technique for fitting the PPBP to a given traffic stream. The PPBP is shown to accurately predict the queueing performance of a sample trace of aggregated Internet traffic. We predict that in few years, natural growth and statistical multiplexing will lead to an efficient optical Internet.

MaxNet: a congestion control architecture for scalable networks

MaxNet is a distributed congestion control architecture. This paper analyzes the stability properties of MaxNet. We show that MaxNet is stable for networks with arbitrary delays, numbers of sources, capacities, and topologies. Unlike existing proposals, MaxNet does not need to estimate the number of bottleneck links on the end-to-end path to achieve these scaling properties.

Blocking probabilities of optical burst switching networks based on reduced load fixed point approximations

This paper provides a framework for analysis and performance evaluation of Optical Burst Switching (OBS) networks. In particular, a new reduced load fixed point approximation model to evaluate blocking probabilities in OBS networks is introduced. The model is versatile enough to cover known OBS reservation policies such as Just-Enough-Time (JET), Just-In-Time (JIT), Burst Segmentation and Route-dependent Priorities. The accuracy of the model is confirmed by simulation and the various policies are compared.