The Experts below are selected from a list of 4716 Experts worldwide ranked by ideXlab platform
S. J.ben Yoo - One of the best experts on this subject based on the ideXlab platform.
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Demonstration of variable-length packet Contention Resolution and packet forwarding in an optical-label switching router
IEEE Photonics Technology Letters, 2004Co-Authors: Zhong Pan, Steven Butt, Sajid Butt, Venkatesh Akella, Haijun Yang, Zuqing Zhu, Jing Cao, S. J.ben YooAbstract:This letter presents experimental demonstrations of variable-length optical packet switching with all-optical Contention Resolution "on the fly" on a packet-by-packet basis by incorporating an optical router controller that examines a packet length field in the optical label. The experimental results show the effectiveness of the Contention Resolution and indicate error-free operation.
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Design and experimental demonstration of a variable-length optical packet routing system with unified Contention Resolution
Journal of Lightwave Technology, 2004Co-Authors: Fei Xue, Jinqiang Yang, Shin Kamei, Zhong Pan, Venkatesh Akella, Haijun Yang, Katsunari Okamoto, Jing Cao, S. J.ben YooAbstract:This paper presents theoretical design, network simulation, implementation, and experimental studies of optical packet routing systems supporting variable-length packets. The optical packet switching network exploits unified Contention Resolution in core routers in three optical domains (wavelength, time, and space) and in edge routers by traffic shaping. The optical router controller and lookup table, implemented in a field-programmable gate array (FPGA), effectively incorporates the Contention Resolution scheme with pipelined arbitration of asynchronously arriving variable-length packets. In addition, real-time performance monitoring based on the strong correlation between the bit-error rates of the optical label and those of the data payload indicates its application in optical time-to-live detection for loop mitigations. Successful systems integration resulted in experimental demonstration of the all-optical packet switching system with Contention Resolution for variable-size packets.
Zhong Pan - One of the best experts on this subject based on the ideXlab platform.
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Demonstration of variable-length packet Contention Resolution and packet forwarding in an optical-label switching router
IEEE Photonics Technology Letters, 2004Co-Authors: Zhong Pan, Steven Butt, Sajid Butt, Venkatesh Akella, Haijun Yang, Zuqing Zhu, Jing Cao, S. J.ben YooAbstract:This letter presents experimental demonstrations of variable-length optical packet switching with all-optical Contention Resolution "on the fly" on a packet-by-packet basis by incorporating an optical router controller that examines a packet length field in the optical label. The experimental results show the effectiveness of the Contention Resolution and indicate error-free operation.
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Design and experimental demonstration of a variable-length optical packet routing system with unified Contention Resolution
Journal of Lightwave Technology, 2004Co-Authors: Fei Xue, Jinqiang Yang, Shin Kamei, Zhong Pan, Venkatesh Akella, Haijun Yang, Katsunari Okamoto, Jing Cao, S. J.ben YooAbstract:This paper presents theoretical design, network simulation, implementation, and experimental studies of optical packet routing systems supporting variable-length packets. The optical packet switching network exploits unified Contention Resolution in core routers in three optical domains (wavelength, time, and space) and in edge routers by traffic shaping. The optical router controller and lookup table, implemented in a field-programmable gate array (FPGA), effectively incorporates the Contention Resolution scheme with pipelined arbitration of asynchronously arriving variable-length packets. In addition, real-time performance monitoring based on the strong correlation between the bit-error rates of the optical label and those of the data payload indicates its application in optical time-to-live detection for loop mitigations. Successful systems integration resulted in experimental demonstration of the all-optical packet switching system with Contention Resolution for variable-size packets.
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End-to-End Contention Resolution Schemes for an Optical Packet Switching Network with Enhanced Edge Routers
Journal of Lightwave Technology, 2003Co-Authors: Fei Xue, Yash Bansal, Minyong Jeon, Shin Kamei, Zhong Pan, Venkatesh Akella, Katsunari Okamoto, Jing Cao, S. J. Ben YooAbstract:This paper investigates Contention Resolution schemes for optical packet switching networks from an end-to-end perspective, where the combined exploitation of both core routers and edge routers are highlighted. For the optical-core network, we present the architecture of an optical router to achieve Contention Resolution in wavelength, time, and space domains. Complementing the solution involving only the core router intelligences, we propose performance enhancement schemes at the network edge, including a traffic-shaping function at the ingress edge and a proper dimensioning of the drop port number at the egress edge. Both schemes prove effective in reducing networkwide packet-loss rates. In particular, scalability performance simulations demonstrate that a considerably low packet-loss rate (0.0001% at load 0.6) is achieved in a 16-wavelength network by incorporating the performance enhancement schemes at the edge with the Contention Resolution schemes in the core. Further, we develop an field-programmable gate-array (FPGA)-based switch controller and integrate it with enabling optical devices to demonstrate the packet-by-packet Contention Resolution. Proof-of-principle experiments involving the prototype core router achieve an error-free low-latency Contention Resolution.
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Optical-label based packet routing system with Contention Resolution in wavelength, time, and space domains
Optical Fiber Communication Conference and Exhibit, 1Co-Authors: S. J. B. Yoo, Zhong Pan, Jing Cao, Y. Bansal, V.k. Tsui, S.k.h. Fong, Yanda Zhang, J. Taylor, Hyuek Jae Lee, Minyong JeonAbstract:We report optical-label switched optical packet routing with wavelength, time, and space domain Contention Resolution. Testing of the packet routing system under three Contention scenarios demonstrated the successful Contention Resolution in the three domains and error free performance.
Jason P. Jue - One of the best experts on this subject based on the ideXlab platform.
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Analysis and implementation of look-ahead window Contention Resolution with QoS support in optical burst-switched networks
IEEE Journal on Selected Areas in Communications, 2006Co-Authors: Farid Farahmand, Jason P. JueAbstract:Optical burst switching (OBS) has been proposed as a promising switching technology to support the next-generation optical Internet. Two critical issues in OBS networks are designing effective Contention Resolution algorithms and implementing such algorithms in the core switch node. The first part of this paper deals with the problem of Contention in OBS networks. We introduce a new Contention Resolution algorithm called Lookahead window Contention Resolution (LCR) that can support service differentiation. Through complexity analysis, a number of important properties of LCR and its variations are examined and verified. We also investigate the performance of LCR in a single core switch node. We show through simulation that the performance of LCR is competitive to existing Contention Resolution mechanisms in terms of reducing burst loss. The second part of this paper presents a practical design approach for a generic control packet processor architecture. Based on the proposed architecture, we implement the look-ahead Contention Resolution algorithm using a high-density field-programmable gate arrays (FPGA). Through hardware test and verification, we evaluate the performance characteristics of the look-ahead Contention Resolution algorithm in terms of hardware speed, scalability, and cost.
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Differentiated Contention Resolution for QoS in photonic packet-switched networks
Journal of Lightwave Technology, 2004Co-Authors: Tao Zhang, Jason P. JueAbstract:Packet Contention is a major challenge in photonic packet-switched networks due to the lack of random access buffers in the optical domain. Existing Contention Resolution approaches such as wavelength conversion and fiber-delay-line buffering may significantly increase the overall system cost and may be difficult to implement. To avoid such issues, this paper proposes a framework for providing label-based differentiated Contention Resolution by exploiting recirculation buffering and deflection routing. To accommodate more options for differentiation and to avoid the potential problem of forwarding packets in a network indefinitely, two classes of loopless deflection algorithms are provided. An analytical model is also developed to evaluate the packet loss probability and the end-to-end delay for different buffering and deflection routing schemes. The paper also investigates the effectiveness of the control schemes in providing differentiated loss and delay through simulation and analysis. The accuracy of the analytical model is confirmed by simulation.
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supporting qos with look ahead window Contention Resolution in optical burst switched networks
Global Communications Conference, 2003Co-Authors: Farid Farahmand, Jason P. JueAbstract:Optical burst switching (OBS) has been proposed as a competitive hybrid switching technology to support the next-generation optical Internet. This paper addresses the problem of Contention in OBS networks and introduces a new Contention Resolution algorithm called look-ahead window Contention Resolution (LCR) that can also support service differentiation. Simulation results show that the performance of LCR is competitive to existing Contention Resolution mechanisms in terms of reducing burst loss.
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Look-ahead window Contention Resolution in optical burst switched networks
Workshop on High Performance Switching and Routing 2003 HPSR., 1Co-Authors: Farid Farahmand, Jason P. JueAbstract:We introduce a new Contention Resolution algorithm called look-ahead window Contention Resolution (LCR). This unique Contention Resolution approach can be used in conjunction with a scheduling technique to reduce the packet loss in an optical burst switched network. We analyze the performance of LCR by means of simulations and compare it with other major existing Contention Resolution policies.
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GLOBECOM - Supporting QoS with look-ahead window Contention Resolution in optical burst switched networks
GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489), 1Co-Authors: Farid Farahmand, Jason P. JueAbstract:Optical burst switching (OBS) has been proposed as a competitive hybrid switching technology to support the next-generation optical Internet. This paper addresses the problem of Contention in OBS networks and introduces a new Contention Resolution algorithm called look-ahead window Contention Resolution (LCR) that can also support service differentiation. Simulation results show that the performance of LCR is competitive to existing Contention Resolution mechanisms in terms of reducing burst loss.
Rico Zenklusen - One of the best experts on this subject based on the ideXlab platform.
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Online Contention Resolution Schemes with Applications to Bayesian Selection Problems
SIAM Journal on Computing, 2021Co-Authors: Moran Feldman, Ola Svensson, Rico ZenklusenAbstract:We introduce a new rounding technique designed for online optimization problems, which is related to Contention Resolution schemes, a technique initially introduced in the context of submodular fun...
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An optimal monotone Contention Resolution scheme for bipartite matchings via a polyhedral viewpoint
Mathematical Programming, 2020Co-Authors: Simon Bruggmann, Rico ZenklusenAbstract:Relaxation and rounding approaches became a standard and extremely versatile tool for constrained submodular function maximization. One of the most common rounding techniques in this context are Contention Resolution schemes. Such schemes round a fractional point by first rounding each coordinate independently, and then dropping some elements to reach a feasible set. Also the second step, where elements are dropped, is typically randomized. This leads to an additional source of randomization within the procedure, which can complicate the analysis. We suggest a different, polyhedral viewpoint to design Contention Resolution schemes, which avoids to deal explicitly with the randomization in the second step. This is achieved by focusing on the marginals of a dropping procedure. Apart from avoiding one source of randomization, our viewpoint allows for employing polyhedral techniques. Both can significantly simplify the construction and analysis of Contention Resolution schemes. We show how, through our framework, one can obtain an optimal monotone Contention Resolution scheme for bipartite matchings, which has a balancedness of 0.4762. So far, only very few results are known about optimality of monotone Contention Resolution schemes. Our Contention Resolution scheme for the bipartite case also improves the lower bound on the correlation gap for bipartite matchings. Furthermore, we derive a monotone Contention Resolution scheme for matchings that significantly improves over the previously best one. More precisely, we obtain a balancedness of 0.4326, improving on a prior 0.1997-balanced scheme. At the same time, our scheme implies that the currently best lower bound on the correlation gap for matchings is not tight. Our results lead to improved approximation factors for various constrained submodular function maximization problems over a combination of matching constraints with further constraints.
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An Optimal Monotone Contention Resolution Scheme for Bipartite Matchings via a Polyhedral Viewpoint
arXiv: Data Structures and Algorithms, 2019Co-Authors: Simon Bruggmann, Rico ZenklusenAbstract:Relaxation and rounding approaches became a standard and extremely versatile tool for constrained submodular function maximization. One of the most common rounding techniques in this context are Contention Resolution schemes. Such schemes round a fractional point by first rounding each coordinate independently, and then dropping some elements to reach a feasible set. Also the second step, where elements are dropped, is typically randomized. This leads to an additional source of randomization within the procedure, which can complicate the analysis. We suggest a different, polyhedral viewpoint to design Contention Resolution schemes, which avoids to deal explicitly with the randomization in the second step. This is achieved by focusing on the marginals of a dropping procedure. Apart from avoiding one source of randomization, our viewpoint allows for employing polyhedral techniques. Both can significantly simplify the construction and analysis of Contention Resolution schemes. We show how, through our framework, one can obtain an optimal monotone Contention Resolution scheme for bipartite matchings. So far, only very few results are known about optimality of monotone Contention Resolution schemes. Our Contention Resolution scheme for the bipartite case also improves the lower bound on the correlation gap for bipartite matchings. Furthermore, we derive a monotone Contention Resolution scheme for matchings that significantly improves over the previously best one. At the same time, our scheme implies that the currently best lower bound on the correlation gap for matchings is not tight. Our results lead to improved approximation factors for various constrained submodular function maximization problems over a combination of matching constraints with further constraints.
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SODA - Online Contention Resolution schemes
Proceedings of the Twenty-Seventh Annual ACM-SIAM Symposium on Discrete Algorithms, 2015Co-Authors: Moran Feldman, Ola Svensson, Rico ZenklusenAbstract:We introduce a new rounding technique designed for online optimization problems, which is related to Contention Resolution schemes, a technique initially introduced in the context of submodular function maximization. Our rounding technique, which we call online Contention Resolution schemes (OCRSs), is applicable to many online selection problems, including Bayesian online selection, oblivious posted pricing mechanisms, and stochastic probing models. It allows for handling a wide set of constraints, and shares many strong properties of offline Contention Resolution schemes. In particular, OCRSs for different constraint families can be combined to obtain an OCRS for their intersection. Moreover, we can approximately maximize submodular functions in the online settings we consider. We, thus, get a broadly applicable framework for several online selection problems, which improves on previous approaches in terms of the types of constraints that can be handled, the objective functions that can be dealt with, and the assumptions on the strength of the adversary. Furthermore, we resolve two open problems from the literature; namely, we present the first constant-factor constrained oblivious posted price mechanism for matroid constraints, and the first constant-factor algorithm for weighted stochastic probing with deadlines.
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Online Contention Resolution Schemes
arXiv: Data Structures and Algorithms, 2015Co-Authors: Moran Feldman, Ola Svensson, Rico ZenklusenAbstract:We introduce a new rounding technique designed for online optimization problems, which is related to Contention Resolution schemes, a technique initially introduced in the context of submodular function maximization. Our rounding technique, which we call online Contention Resolution schemes (OCRSs), is applicable to many online selection problems, including Bayesian online selection, oblivious posted pricing mechanisms, and stochastic probing models. It allows for handling a wide set of constraints, and shares many strong properties of offline Contention Resolution schemes. In particular, OCRSs for different constraint families can be combined to obtain an OCRS for their intersection. Moreover, we can approximately maximize submodular functions in the online settings we consider. We, thus, get a broadly applicable framework for several online selection problems, which improves on previous approaches in terms of the types of constraints that can be handled, the objective functions that can be dealt with, and the assumptions on the strength of the adversary. Furthermore, we resolve two open problems from the literature; namely, we present the first constant-factor constrained oblivious posted price mechanism for matroid constraints, and the first constant-factor algorithm for weighted stochastic probing with deadlines.
Jing Cao - One of the best experts on this subject based on the ideXlab platform.
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Demonstration of variable-length packet Contention Resolution and packet forwarding in an optical-label switching router
IEEE Photonics Technology Letters, 2004Co-Authors: Zhong Pan, Steven Butt, Sajid Butt, Venkatesh Akella, Haijun Yang, Zuqing Zhu, Jing Cao, S. J.ben YooAbstract:This letter presents experimental demonstrations of variable-length optical packet switching with all-optical Contention Resolution "on the fly" on a packet-by-packet basis by incorporating an optical router controller that examines a packet length field in the optical label. The experimental results show the effectiveness of the Contention Resolution and indicate error-free operation.
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Design and experimental demonstration of a variable-length optical packet routing system with unified Contention Resolution
Journal of Lightwave Technology, 2004Co-Authors: Fei Xue, Jinqiang Yang, Shin Kamei, Zhong Pan, Venkatesh Akella, Haijun Yang, Katsunari Okamoto, Jing Cao, S. J.ben YooAbstract:This paper presents theoretical design, network simulation, implementation, and experimental studies of optical packet routing systems supporting variable-length packets. The optical packet switching network exploits unified Contention Resolution in core routers in three optical domains (wavelength, time, and space) and in edge routers by traffic shaping. The optical router controller and lookup table, implemented in a field-programmable gate array (FPGA), effectively incorporates the Contention Resolution scheme with pipelined arbitration of asynchronously arriving variable-length packets. In addition, real-time performance monitoring based on the strong correlation between the bit-error rates of the optical label and those of the data payload indicates its application in optical time-to-live detection for loop mitigations. Successful systems integration resulted in experimental demonstration of the all-optical packet switching system with Contention Resolution for variable-size packets.
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End-to-End Contention Resolution Schemes for an Optical Packet Switching Network with Enhanced Edge Routers
Journal of Lightwave Technology, 2003Co-Authors: Fei Xue, Yash Bansal, Minyong Jeon, Shin Kamei, Zhong Pan, Venkatesh Akella, Katsunari Okamoto, Jing Cao, S. J. Ben YooAbstract:This paper investigates Contention Resolution schemes for optical packet switching networks from an end-to-end perspective, where the combined exploitation of both core routers and edge routers are highlighted. For the optical-core network, we present the architecture of an optical router to achieve Contention Resolution in wavelength, time, and space domains. Complementing the solution involving only the core router intelligences, we propose performance enhancement schemes at the network edge, including a traffic-shaping function at the ingress edge and a proper dimensioning of the drop port number at the egress edge. Both schemes prove effective in reducing networkwide packet-loss rates. In particular, scalability performance simulations demonstrate that a considerably low packet-loss rate (0.0001% at load 0.6) is achieved in a 16-wavelength network by incorporating the performance enhancement schemes at the edge with the Contention Resolution schemes in the core. Further, we develop an field-programmable gate-array (FPGA)-based switch controller and integrate it with enabling optical devices to demonstrate the packet-by-packet Contention Resolution. Proof-of-principle experiments involving the prototype core router achieve an error-free low-latency Contention Resolution.
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Optical-label based packet routing system with Contention Resolution in wavelength, time, and space domains
Optical Fiber Communication Conference and Exhibit, 1Co-Authors: S. J. B. Yoo, Zhong Pan, Jing Cao, Y. Bansal, V.k. Tsui, S.k.h. Fong, Yanda Zhang, J. Taylor, Hyuek Jae Lee, Minyong JeonAbstract:We report optical-label switched optical packet routing with wavelength, time, and space domain Contention Resolution. Testing of the packet routing system under three Contention scenarios demonstrated the successful Contention Resolution in the three domains and error free performance.