The Experts below are selected from a list of 25119 Experts worldwide ranked by ideXlab platform
Moshe Zukerman - One of the best experts on this subject based on the ideXlab platform.
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Computation of Blocking Probability for Large Circuit Switched Networks
IEEE Communications Letters, 2012Co-Authors: Vyacheslav M. Abramov, Eric Wong, Meiqian Wang, Moshe ZukermanAbstract:The ever-growing Internet and the mounting evidence to the important role of circuit switching motivate the need for an accurate and scalable means for performance evaluation of large circuit switched networks. Previous work has shown that the Erlang Fixed Point Approximation (EFPA) achieves accurate results for such networks where the number of channels (circuits) per link is large. However, a conventional application of EFPA for large networks is computationally prohibitive. In cases where the EFPA solution is unattainable, we propose, in this paper, to use an asymptotic approximation, which we call A-EFPA, for the link Blocking Probability and demonstrate savings of many orders of magnitudes in computation time for Blocking Probability approximation in realistically sized networks with large number of circuits per link. We demonstrate for NSFNet and Internet2 accurate calculations of the Blocking Probability using simulations, EFPA and A-EFPA, where each of these three methods is used for a different range of parameter values.
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Sensitivity of Blocking Probability in the Generalized Engset Model for OBS
IEEE Communications Letters, 2011Co-Authors: Jianan Zhang, Eric Wong, Yu Peng, Moshe ZukermanAbstract:The generalized Engset model can be applied to evaluate the Blocking Probability at an optical cross connect (OXC) of bufferless optical burst switching (OBS) system. For tractability, previous studies assumed that burst transmission time (on-time) and time intervals between bursts provided by the same input channel (off-time) are exponentially distributed. Here we aim to study the sensitivity of Blocking Probability to the shape of these distributions. Extensive numerical results demonstrate that the Blocking Probability is not very sensitive to on- and off-time distributions in general. We observe that higher variance of on- and off-time distributions may lead to better performance.
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a new method for Blocking Probability evaluation in obs ops networks with deflection routing
Journal of Lightwave Technology, 2009Co-Authors: Eric Wong, Andrew Zalesky, Moshe Zukerman, J. Baliga, Garvesh RaskuttiAbstract:In this paper, we present a new method for the estimation of Blocking probabilities in bufferless optical burst or packet switched networks. In such networks, deflection routing is used to reduce Blocking Probability. However, it requires certain wastage due to trunk reservation that must be used to avoid instability. We provide a wide range of simulation and numerical results to validate our new approximation method and demonstrate various effects on Blocking Probability and utilization, such as network size, trunk size, the maximal number of allowable deflections, and burst/packet length.
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A New Method for Blocking Probability Evaluation in OBS/OPS Networks With Deflection Routing
Journal of Lightwave Technology, 2009Co-Authors: Eric Wong, Andrew Zalesky, Moshe Zukerman, J. Baliga, Garvesh RaskuttiAbstract:In this paper, we present a new method for the estimation of Blocking probabilities in bufferless optical burst or packet switched networks. In such networks, deflection routing is used to reduce Blocking Probability. However, it requires certain wastage due to trunk reservation that must be used to avoid instability. We provide a wide range of simulation and numerical results to validate our new approximation method and demonstrate various effects on Blocking Probability and utilization, such as network size, trunk size, the maximal number of allowable deflections, and burst/packet length.
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a new method for approximating Blocking Probability in overflow loss networks
Computer Networks, 2007Co-Authors: Eric Wong, Andrew Zalesky, Z Rosberg, Moshe ZukermanAbstract:In this paper, we present a new approximation for estimating Blocking Probability in overflow loss networks and systems. Given a system for which an estimate of Blocking Probability is sought, we first construct a second system to act as a surrogate for the original system. Estimating Blocking Probability in the second system with Erlang's fixed point approximation (EFPA) provides a better estimate for Blocking Probability in the original system than if we were to use the conventional approach of directly using EFPA in the original system. We present a combination of numerical and theoretical results that indicate our new approximation offers a better estimate than EFPA for a certain pure overflow loss network. Moreover, we demonstrate the accuracy of our new approximation for circuit-switched networks using alternative routing. We argue that the success of our new approximation is due to its ability to utilize congestion information imbedded in overflow traffic, whereas the conventional approach fails to utilize such information.
Xiaohong Jiang - One of the best experts on this subject based on the ideXlab platform.
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Blocking Probability analysis for optical banyan networks with link failure
IEEE Transactions on Communications, 2018Co-Authors: Xiaohong Jiang, Achille PattavinaAbstract:Highly fault-tolerant optical switch is becoming a critical network element for large wavelength division multiplexing mesh networks. Optical nodes built on replicated banyan network (RBN) structures are attractive for serving as optical switching systems due to the nice properties of banyan network structures. Furthermore it is expected that an optical RBN structure also has a good fault-tolerant capability because it consists of multiple identical banyan networks. Previous analytical models have been developed to understand the Blocking behaviors of optical RBN networks without taking into account the link failure in optical RBN networks. In this paper, we conduct the link failure-tolerant analysis of optical RBN networks and present an analytical model for the Blocking Probability of optical RBN networks when link failures are taken into account. The model is significant because it provides network developers a quantitative guidance to determine the effects of network failure on the overall Blocking behaviors of optical RBN networks and enables a desirable tradeoff to be made between Blocking Probability and hardware cost in a faulty optical RBN network.
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Blocking Probability of vertically stacked optical banyan networks under random routing
Global Communications Conference, 2003Co-Authors: Xiaohong Jiang, Hong Shen, Susumu HoriguchiAbstract:Vertical stacking of optical banyan networks is an attractive scheme for building nonBlocking (crosstalk-free) optical switching networks. The resulting networks, namely vertically stacked optical banyan (VSOB) networks, preserve all the good properties of banyan networks, but increase the hardware cost significantly. In this paper, we study the Blocking probabilities of VSOB networks under random routing strategy, and develop a model to compute the Blocking probabilities with respect to the number of planes in the networks. Our model calculates the Blocking probabilities stage by stage recursively, and it depicts accurately the Blocking behaviors of VSOB networks under random routing. The proposed model is significant because it reveals the inherent relationships between Blocking Probability and network hardware cost in terms of the number of planes, and provides network developers a quantitative guidance to find a desirable tradeoff between Blocking Probability and hardware cost. An important conclusion drawn from our work that has practical applications is that the hardware cost of a VSOB network can be reduced dramatically if a predictable and almost negligible non-zero Blocking Probability is allowed.
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ICC - Blocking Probability modeling of distensible optical banyan networks
IEEE International Conference on Communications 2005. ICC 2005. 2005, 1Co-Authors: Xiaohong Jiang, Susumu Horiguchi, H.t. MouftahAbstract:Horizontally expanded and vertically stacked optical banyan (HVOB) is a general architecture for constructing banyan-based optical switches. Blocking analysis is an effective approach to studying network performance and finding a graceful compromise among hardware cost, network depth and Blocking Probability; however, little has been done on analyzing the Blocking behavior of general HVOB networks. In this paper, we study the overall Blocking behavior of a HVOB network, where an upper bound on the Blocking Probability of the network is developed. The upper bound depicts accurately the overall performance behavior of a HVOB network as verified by extensive simulation results and it agrees with the strictly nonBlocking condition of the network. The derived upper bound is significant because it reveals the inherent relationship among Blocking Probability, network depth, and network hardware cost, by which a desirable tradeoff can be made among them. In particular, our bound provides network developers an effective tool to estimate the maximum Blocking Probability of a HVOB network in which different routing algorithms can be applied with a guaranteed performance in terms of Blocking Probability, hardware cost and network depth. An important conclusion drawn from our work is that the hardware cost of HVOB networks can be reduced dramatically without introducing either significantly high Blocking Probability or a large network depth.
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GLOBECOM - Blocking Probability of vertically stacked optical banyan networks under random routing
GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489), 1Co-Authors: Xiaohong Jiang, Hong Shen, Susumu HoriguchiAbstract:Vertical stacking of optical banyan networks is an attractive scheme for building nonBlocking (crosstalk-free) optical switching networks. The resulting networks, namely vertically stacked optical banyan (VSOB) networks, preserve all the good properties of banyan networks, but increase the hardware cost significantly. In this paper, we study the Blocking probabilities of VSOB networks under random routing strategy, and develop a model to compute the Blocking probabilities with respect to the number of planes in the networks. Our model calculates the Blocking probabilities stage by stage recursively, and it depicts accurately the Blocking behaviors of VSOB networks under random routing. The proposed model is significant because it reveals the inherent relationships between Blocking Probability and network hardware cost in terms of the number of planes, and provides network developers a quantitative guidance to find a desirable tradeoff between Blocking Probability and hardware cost. An important conclusion drawn from our work that has practical applications is that the hardware cost of a VSOB network can be reduced dramatically if a predictable and almost negligible non-zero Blocking Probability is allowed.
Eric Wong - One of the best experts on this subject based on the ideXlab platform.
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extreme learning machine for estimating Blocking Probability of bufferless obs ops networks
Journal of Optical Communications and Networking, 2017Co-Authors: Ho Chun Leung, Chi-sing Leung, Eric WongAbstract:Recently, the neural network approach for the Blocking Probability evaluation on optical networks was proposed, in which the inputs of the neural network were the optical network parameters and the output was the Blocking Probability of the optical network. The numerical results showed that its evaluation speed of the Blocking Probability was thousands of times faster than that of the discrete event simulator. However, the existing approach had two drawbacks. First, when the Blocking Probability was small, there was a significant approximation error due to the high dynamic range of the Blocking Probability. Second, the single-hidden-layer feedforward network model was used, which needed some time-consuming training algorithms to learn the parameters of hidden nodes, such as backpropagation. To solve these problems, this paper proposes to use the mean squared error of the log Blocking Probability as the training objective and use the extreme learning machine (ELM) framework for the training. Our numerical results show that the Blocking Probability estimated by our training objective is much more accurate than that of the existing approach, and it is obtained efficiently due to the greatly simplified training procedure offered by the ELM.
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Extreme Learning Machine for Estimating Blocking Probability of Bufferless OBS/OPS Networks
Journal of Optical Communications and Networking, 2017Co-Authors: Ho Chun Leung, Chi-sing Leung, Eric WongAbstract:Recently, the neural network approach for the Blocking Probability evaluation on optical networks was proposed, in which the inputs of the neural network were the optical network parameters and the output was the Blocking Probability of the optical network. The numerical results showed that its evaluation speed of the Blocking Probability was thousands of times faster than that of the discrete event simulator. However, the existing approach had two drawbacks. First, when the Blocking Probability was small, there was a significant approximation error due to the high dynamic range of the Blocking Probability. Second, the single-hidden-layer feedforward network model was used, which needed some time-consuming training algorithms to learn the parameters of hidden nodes, such as backpropagation. To solve these problems, this paper proposes to use the mean squared error of the log Blocking Probability as the training objective and use the extreme learning machine (ELM) framework for the training. Our numerical results show that the Blocking Probability estimated by our training objective is much more accurate than that of the existing approach, and it is obtained efficiently due to the greatly simplified training procedure offered by the ELM.
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Computation of Blocking Probability for Large Circuit Switched Networks
IEEE Communications Letters, 2012Co-Authors: Vyacheslav M. Abramov, Eric Wong, Meiqian Wang, Moshe ZukermanAbstract:The ever-growing Internet and the mounting evidence to the important role of circuit switching motivate the need for an accurate and scalable means for performance evaluation of large circuit switched networks. Previous work has shown that the Erlang Fixed Point Approximation (EFPA) achieves accurate results for such networks where the number of channels (circuits) per link is large. However, a conventional application of EFPA for large networks is computationally prohibitive. In cases where the EFPA solution is unattainable, we propose, in this paper, to use an asymptotic approximation, which we call A-EFPA, for the link Blocking Probability and demonstrate savings of many orders of magnitudes in computation time for Blocking Probability approximation in realistically sized networks with large number of circuits per link. We demonstrate for NSFNet and Internet2 accurate calculations of the Blocking Probability using simulations, EFPA and A-EFPA, where each of these three methods is used for a different range of parameter values.
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Sensitivity of Blocking Probability in the Generalized Engset Model for OBS
IEEE Communications Letters, 2011Co-Authors: Jianan Zhang, Eric Wong, Yu Peng, Moshe ZukermanAbstract:The generalized Engset model can be applied to evaluate the Blocking Probability at an optical cross connect (OXC) of bufferless optical burst switching (OBS) system. For tractability, previous studies assumed that burst transmission time (on-time) and time intervals between bursts provided by the same input channel (off-time) are exponentially distributed. Here we aim to study the sensitivity of Blocking Probability to the shape of these distributions. Extensive numerical results demonstrate that the Blocking Probability is not very sensitive to on- and off-time distributions in general. We observe that higher variance of on- and off-time distributions may lead to better performance.
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a new method for Blocking Probability evaluation in obs ops networks with deflection routing
Journal of Lightwave Technology, 2009Co-Authors: Eric Wong, Andrew Zalesky, Moshe Zukerman, J. Baliga, Garvesh RaskuttiAbstract:In this paper, we present a new method for the estimation of Blocking probabilities in bufferless optical burst or packet switched networks. In such networks, deflection routing is used to reduce Blocking Probability. However, it requires certain wastage due to trunk reservation that must be used to avoid instability. We provide a wide range of simulation and numerical results to validate our new approximation method and demonstrate various effects on Blocking Probability and utilization, such as network size, trunk size, the maximal number of allowable deflections, and burst/packet length.
Garvesh Raskutti - One of the best experts on this subject based on the ideXlab platform.
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a new method for Blocking Probability evaluation in obs ops networks with deflection routing
Journal of Lightwave Technology, 2009Co-Authors: Eric Wong, Andrew Zalesky, Moshe Zukerman, J. Baliga, Garvesh RaskuttiAbstract:In this paper, we present a new method for the estimation of Blocking probabilities in bufferless optical burst or packet switched networks. In such networks, deflection routing is used to reduce Blocking Probability. However, it requires certain wastage due to trunk reservation that must be used to avoid instability. We provide a wide range of simulation and numerical results to validate our new approximation method and demonstrate various effects on Blocking Probability and utilization, such as network size, trunk size, the maximal number of allowable deflections, and burst/packet length.
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A New Method for Blocking Probability Evaluation in OBS/OPS Networks With Deflection Routing
Journal of Lightwave Technology, 2009Co-Authors: Eric Wong, Andrew Zalesky, Moshe Zukerman, J. Baliga, Garvesh RaskuttiAbstract:In this paper, we present a new method for the estimation of Blocking probabilities in bufferless optical burst or packet switched networks. In such networks, deflection routing is used to reduce Blocking Probability. However, it requires certain wastage due to trunk reservation that must be used to avoid instability. We provide a wide range of simulation and numerical results to validate our new approximation method and demonstrate various effects on Blocking Probability and utilization, such as network size, trunk size, the maximal number of allowable deflections, and burst/packet length.
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enhanced Blocking Probability evaluation method for circuit switched trunk reservation networks
IEEE Communications Letters, 2007Co-Authors: Garvesh Raskutti, Andrew Zalesky, Eric Wong, Moshe ZukermanAbstract:We consider the problem of estimating steady-state Blocking Probability for circuit-switched networks that allow alternate routing with particular emphasis on networks protected by trunk reservation. We use a recently proposed Blocking Probability estimate, the Overflow Priority Classification Approximation (OPCA) as an alternative to the currently used Erlang's Fixed-Point Approximation (EFPA). We demonstrate empirically that OPCA provides a better Blocking estimate than EFPA for circuit-switched networks with alternate routing, that are reasonably protected by trunk reservation.
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Blocking Probability estimation for trunk reservation networks
International Conference on Communications, 2007Co-Authors: Garvesh Raskutti, Andrew Zalesky, Eric Wong, Moshe ZukermanAbstract:In this paper, we consider the problem of estimating steady-state Blocking Probability for circuit-switched networks with alternate routing. In particular, we focus on networks protected by trunk reservation. A new Blocking Probability estimate, the so-called overflow priority classification approximation (OPCA), is considered as an alternative to the currently used the Erlang fixed-point approximation (EFPA). OPCA is applied to the case of arbitrary circuit-switched networks with trunk reservation. We show through empirical results that OPCA yields a superior estimate for Blocking Probability compared to EFPA for circuit-switched networks with alternate routing that are reasonably protected against instability by trunk reservation.
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ICC - Blocking Probability Estimation for Trunk Reservation Networks
2007 IEEE International Conference on Communications, 2007Co-Authors: Garvesh Raskutti, Andrew Zalesky, Eric Wong, Moshe ZukermanAbstract:In this paper, we consider the problem of estimating steady-state Blocking Probability for circuit-switched networks with alternate routing. In particular, we focus on networks protected by trunk reservation. A new Blocking Probability estimate, the so-called overflow priority classification approximation (OPCA), is considered as an alternative to the currently used the Erlang fixed-point approximation (EFPA). OPCA is applied to the case of arbitrary circuit-switched networks with trunk reservation. We show through empirical results that OPCA yields a superior estimate for Blocking Probability compared to EFPA for circuit-switched networks with alternate routing that are reasonably protected against instability by trunk reservation.
Danny H K Tsang - One of the best experts on this subject based on the ideXlab platform.
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proportional qos over wdm networks Blocking Probability
International Symposium on Computers and Communications, 2001Co-Authors: Yang Chen, Mounir Hamdi, Danny H K TsangAbstract:The provision of scalable quality-of-service (QoS) guarantees on wavelength-division-multiplexing (WDM) networks is an important and challenging issue for the next generation Internet. One of the important performance metrics in a QoS-capable WDM network is the call Blocking Probability. Previously, a proportional differentiation model has been proposed as an effective method for scalable differentiated services provision. This model provides the network operators the ability of quantitatively adjusting the quality differentiation between service classes. We introduce this model into WDM networks with the aim of providing proportionally differentiated Blocking Probability to various traffic classes. An intentional Blocking algorithm is proposed to implement this model at the wavelength level. In order to solve the link utilization degradation in this algorithm, we propose another intentional termination algorithm. Since the performance requirement from the network operator might be various, a hybrid algorithm is also given as a balance between the above two. These three algorithms are also suitable to TDM over WDM, where one connection only take part of the transmission capacity of one wavelength. Extensive simulation results demonstrate that our algorithms provide accurate and controllable differentiation on Blocking Probability between various traffic classes even in a bursty traffic situation. The infeasibility problem in proportional Blocking Probability provision is also discussed.
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ISCC - Proportional QoS over WDM networks: Blocking Probability
Proceedings. Sixth IEEE Symposium on Computers and Communications, 1Co-Authors: Yang Chen, Mounir Hamdi, Danny H K TsangAbstract:The provision of scalable quality-of-service (QoS) guarantees on wavelength-division-multiplexing (WDM) networks is an important and challenging issue for the next generation Internet. One of the important performance metrics in a QoS-capable WDM network is the call Blocking Probability. Previously, a proportional differentiation model has been proposed as an effective method for scalable differentiated services provision. This model provides the network operators the ability of quantitatively adjusting the quality differentiation between service classes. We introduce this model into WDM networks with the aim of providing proportionally differentiated Blocking Probability to various traffic classes. An intentional Blocking algorithm is proposed to implement this model at the wavelength level. In order to solve the link utilization degradation in this algorithm, we propose another intentional termination algorithm. Since the performance requirement from the network operator might be various, a hybrid algorithm is also given as a balance between the above two. These three algorithms are also suitable to TDM over WDM, where one connection only take part of the transmission capacity of one wavelength. Extensive simulation results demonstrate that our algorithms provide accurate and controllable differentiation on Blocking Probability between various traffic classes even in a bursty traffic situation. The infeasibility problem in proportional Blocking Probability provision is also discussed.
