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Biswanath Mukherjee - One of the best experts on this subject based on the ideXlab platform.
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Survivable WDM mesh networks
Journal of Lightwave Technology, 2003Co-Authors: S. Ramamurthy, L. Sahasrabuddhe, Biswanath MukherjeeAbstract:In a wavelength-division-multiplexing (WDM) optical network, the failure of network elements (e.g., fiber Links and cross connects) may cause the failure of several optical channels, thereby leading to large data losses. This study examines different approaches to protect a mesh-based WDM optical network from such failures. These approaches are based on two survivability paradigms: 1) path Protection/restoration and 2) Link Protection/restoration. The study examines the wavelength capacity requirements, and routing and wavelength assignment of primary and backup paths for path and Link Protection and proposes distributed protocols for path and Link restoration. The study also examines the Protection-switching time and the restoration time for each of these schemes, and the susceptibility of these schemes to multiple Link failures. The numerical results obtained for a representative network topology with random traffic demands demonstrate that there is a tradeoff between the capacity utilization and the susceptibility to multiple Link failures. We find that, on one hand, path Protection provides significant capacity savings over Link Protection, and shared Protection provides significant savings over dedicated Protection; while on the other hand, path Protection is more susceptible to multiple Link failures than Link Protection, and shared Protection is more susceptible to multiple Link failures than dedicated Protection. We formulate a model of Protection-switching times for the different Protection schemes based on a fully distributed control network. We propose distributed control protocols for path and Link restoration. Numerical results obtained by simulating these protocols indicate that, for a representative network topology, path restoration has a better restoration efficiency than Link restoration, and Link restoration has a faster restoration time compared with path restoration.
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survivable wdm mesh networks part i Protection
International Conference on Computer Communications, 1999Co-Authors: S. Ramamurthy, Biswanath MukherjeeAbstract:This investigation considers optical networks which employ wavelength cross-connects that enable the establishment of wavelength-division-multiplexed (WDM) channels, between node-pairs. In such and other networks, the failure of a network element (e.g., fiber Link, cross-connect, etc.) may cause the failure of several optical channels, thereby leading to large data losses. This study examines different approaches to protect mesh based WDM optical networks from single-Link failures. These approaches are based on two basic survivability paradigms: (a) path Protection/restoration, and (b) Link Protection/restoration. In path- and Link-Protection schemes, backup paths and wavelengths are reserved in advance at the time of call setup. Path- and Link-restoration schemes are dynamic schemes in which backup paths are discovered (from the spare capacity in the network) upon the occurrence of a failure. In part 1 of this study presented in this paper, we formulated integer linear programs to determine the capacity requirements for the above Protection schemes for a static traffic demand.
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INFOCOM - Survivable WDM mesh networks. Part I-Protection
IEEE INFOCOM '99. Conference on Computer Communications. Proceedings. Eighteenth Annual Joint Conference of the IEEE Computer and Communications Socie, 1999Co-Authors: S. Ramamurthy, Biswanath MukherjeeAbstract:This investigation considers optical networks which employ wavelength cross-connects that enable the establishment of wavelength-division-multiplexed (WDM) channels, between node-pairs. In such and other networks, the failure of a network element (e.g., fiber Link, cross-connect, etc.) may cause the failure of several optical channels, thereby leading to large data losses. This study examines different approaches to protect mesh based WDM optical networks from single-Link failures. These approaches are based on two basic survivability paradigms: (a) path Protection/restoration, and (b) Link Protection/restoration. In path- and Link-Protection schemes, backup paths and wavelengths are reserved in advance at the time of call setup. Path- and Link-restoration schemes are dynamic schemes in which backup paths are discovered (from the spare capacity in the network) upon the occurrence of a failure. In part 1 of this study presented in this paper, we formulated integer linear programs to determine the capacity requirements for the above Protection schemes for a static traffic demand.
Oliver W. W. Yang - One of the best experts on this subject based on the ideXlab platform.
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BROADNETS - Performance study of self-repairing unicast hierarchical Protection trees in mesh networks
2007 Fourth International Conference on Broadband Communications Networks and Systems (BROADNETS '07), 2007Co-Authors: Shahram Shah-heydari, Oliver W. W. YangAbstract:Protection trees have been used in the past for protecting multicast and unicast traffic in networks in various scenarios. In this paper we focus on shared Protection trees for Link Protection in unicast mesh networks. We present a heuristic algorithm that reduces the redundant capacity required for Protection on shared trees, and improves the restorability of the network. We use simulation of random mesh graphs to compute the performance improvement for various network sizes.
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A distributed hierarchial p-tree Link Protection scheme for mesh networks
Network Architectures Management and Applications, 2004Co-Authors: Shahram Shah-heydari, Oliver W. W. YangAbstract:This paper presents a distributed scheme for Link failure recovery in mesh optical networks, based on the use of network hierarchical spanning trees. The scheme intends to maximize restorability in a network with known working and spare capacities. The hierarchical Protection tree (p-tree) provides the hierarchical layering of the network. The straddling Links that are not located on the tree are protected through tree branches to the higher layer Parent nodes. The Links on the tree are protected by Links to backup parent nodes. We study the problem of finding the most optimized network tree to achieve maximum restorability, and present heuristics for finding the best tree. Our algorithm includes two steps: Selection of the best root node for the tree, and construction of the tree based on distribution of tree ID labels among the nodes. Each node selects a primary parent node and a backup parent node, and constructs pre-determined Protection paths accordingly. In case of failure, all connections on a Link are switched quickly to the Protection path as a bundle. We perform restorability analysis for several real and arbitrary long-haul networks and show that our scheme provides excellent network restorability along with exceptional scalability and maintainability.
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Hierarchical Protection Tree Scheme for Failure Recovery in Mesh Networks
Photonic Network Communications, 2004Co-Authors: Shahram Shah-heydari, Oliver W. W. YangAbstract:This paper presents a novel technique for Link Protection in mesh networks based on the use of hierarchical trees. The hierarchical Protection tree (or p-tree) provides hierarchical layering of the network. The straddling Links that are not located in the tree are protected through tree branches to higher-layer Parent nodes. The Links in the tree are protected by Links to backup parent nodes. This scheme offers several advantages such as scalability, failure impact restriction, and distributed processing. We provide a mathematical analysis to compute performance measures for our Link Protection scheme, and perform restorability analysis for several real and arbitrary long haul networks to compare our scheme to other Link Protection proposals. Our results demonstrate the applicability of hierarchical p-tree Link Protection schemes in real long-haul networks.
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A tree-based Link Protection algorithm
CCECE 2003 - Canadian Conference on Electrical and Computer Engineering. Toward a Caring and Humane Technology (Cat. No.03CH37436), 1Co-Authors: H. Liu, Oliver W. W. Yang, S. Shah-heydariAbstract:High-speed network needs efficient Protection scheme. This paper studies the tree-based Link Protection and restoration method in optical mesh network. Two logical trees can be overlain on a physical network for Protection of the physical Links and nodes. The nontree Links are protected by either of the trees, while the tree Links can be protected by one or both trees. A new algorithm is presented here on how to build two trees on a physical network. These two trees can share the same edge if their directions are different, thus reducing the overall restoration capacity, and minimizing the network total cost. Performance analysis of the algorithm executed in some existing network is presented. We can show that with this scheme the time complexity will reduce compared with the two-stage P-cycle optimization method. Also, in the best case, this scheme can get the optimization restorability result.
Zhu Yong-l - One of the best experts on this subject based on the ideXlab platform.
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Low voltage ride through characteristics of direct-driven wind turbine system based on DC-Link Protection
Chinese Journal of Power Sources, 2014Co-Authors: Zhu Yong-lAbstract:The low voltage ride through(LVRT) characteristics of permanent magnet synchronous generator(PMSG)based on DC-Link Protection circuit during grid faults were studied. The demands of Chinese new national grid code GB/T 19963-2011 for LVRT characteristics of wind turbine were analyzed. Combined with the operating theory of PMSG wind turbine, system control model of PMSG was built under PSCAD conditions. The LVRT characteristics of PMSG with and without DC-Link Protection circuit were analyzed and compared throurh three-phase symmetrical short-circuit faults on grid side. Simulation results show that the models and control methods are correct and valid,and show that PMSG equipped with DC-Link Protection circuit has predominant LVRT capability.
Hiroyoshi Miwa - One of the best experts on this subject based on the ideXlab platform.
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AINA Workshops - Efficient Method for Link Protection Under Multiple Constraints Using ZDD.
Advances in Intelligent Systems and Computing, 2020Co-Authors: Masataka Akasaka, Hiroyoshi MiwaAbstract:It is an important issue to design a highly reliable information network that is robust against network failures. As a method for design of a robust network, there is an approach of Protection, which decreases Link failure probability by backup mechanism and fast recovery mechanism. It is desirable to protect all Links; however, Link Protection needs much cost. Therefore, it is necessary to find the small number of Links to be protected so that a network resulting from failure of any non-protected Links satisfies constraints of quality. In this paper, we propose a method to design an information network satisfying multiple constraints by using an efficient data structure, Zero-suppressed Binary Decision Diagram (ZDD). This method holds the set of the feasible solutions satisfying each constraint by ZDD, and it determines the intersection of the sets of the feasible solutions for all constraints by the calculation of ZDD. Thus, the method can determine the sets of the feasible solutions satisfying the multiple constraints simultaneously, and finally it determines the optimum solution. This approach also makes it easy to change or to add constraints.
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EIDWT - Optimization Problem for Network Design by Link Protection and Link Augmentation
Advances in Internet Data and Web Technologies, 2020Co-Authors: Hiroki Yano, Hiroyoshi MiwaAbstract:Information networks need high reliability. Although Link failure is one of the causes of communication disconnection in networks, it is necessary to be able to continue communication even in such a failure. There are two approaches of Link Protection and Link addition against Link failure. Link Protection is to make the failure probability of Links sufficiently small by sufficient backup resource and rapid recovery system. Link addition is to increase network connectivity by adding new Links to a network. Both Link addition and Link Protection are methods to design a reliable network. Some network design methods either only by Link addition or only by Link Protection have been investigated so far. However, it is possible to design a reliable network at lower cost by a combination of Link addition and Protection than a network designed either by only Link addition or by only Link Protection. In this paper, we deal with a network design problem to realize a reliable network at lower cost by combining Link addition and Link Protection. First, we formulate this network design problem as a decision problem and we prove the NP-hardness. Furthermore, we propose some polynomial-time algorithms for the problems of the optimization version under some restricted conditions.
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INCoS - Network Design Method by Link Protection Considering Probability of Simultaneously Links Failure
Advances in Intelligent Networking and Collaborative Systems, 2019Co-Authors: Keyaki Uji, Hiroyoshi MiwaAbstract:Information networks are required to be reliable. It is important to design robust networks that are resistant to network failure. For that propose, it is necessary to decrease the failure probability of Links by the backup resource and the fast recovery mechanism and so on. However, it costs very much to protect all the Links. Therefore, it is necessary to preferentially protect only some highly required Links and improve the reliability of the entire network. In this paper, we consider the simultaneously failure of Links. A set of Links has the probability that all the Links in the set simultaneously are broken. When a family of the sets is given, we address the network design maximizing the network reliability (the probability that the entire network is connected) by protecting the limited number of Links. We formulate this network design problem and propose a polynomial-time heuristic algorithm. Furthermore, we evaluate the performance by using the topology of some actual information networks, and we show that the proposed algorithm works well.
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INCoS - Network Design Method by Link Protection to Keep Connectivity and Communication Quality to Servers
Advances in Intelligent Networking and Collaborative Systems, 2017Co-Authors: Daishi Irie, Hiroyoshi MiwaAbstract:Information network must be sufficiently reliable. The most reliable method is to protect all Links so that the failure probability of a Link is sufficiently small by sufficient backup resource and rapid recovery system. However, as Link Protection needs much cost, it is necessary to find the smallest number of Links to be protected so that a network resulting from failures of any non-protected Links can provide sufficient connectivity. Especially, in content delivery services, a request from a user is navigated to one of the mirror servers so that small delay time and balance of loads can be achieved; the network topology must be designed so that the navigation can be efficiently achieved even after failure. In this paper, we focus on the problem of finding the protected Links so that the conditions that include the stretch factor and the fragmentation factor are satisfied. First, we formulate this problem and prove that this problem is NP-hard. Next, we present a polynomial-time algorithm to solve the problem that the number of the simultaneous Link failures is restricted to one. Furthermore, we present a polynomial-time approximation algorithm with the approximation ratio of a constant that is the number of the simultaneous Link failures. In addition, we apply the approximation algorithms to the topology of actual networks and evaluate the approximation ratio.
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network design method based on Link Protection taking account of the connectivity and distance between sites
Intelligent Networking and Collaborative Systems, 2016Co-Authors: Tsuyoshi Yamasaki, Makoto Anan, Hiroyoshi MiwaAbstract:High reliability is required in networks, and it is important to build robust networks that are tolerant to network failures. In content delivery services in particular, service interruptions due to disconnection of communication paths between the server and nodes that receive the service must be avoided. Content delivery services use a master server that contains the original content and multiple edge-servers (mirror servers) that hold copies of the content so that communication paths exist between the master server and the edge-servers even in the event of a failure. In addition to the guarantee of network connectivity, large increases in path lengths when changing from the paths used during normal operation to alternative paths in the event of a failure must be avoided from the viewpoint of suppressing degradation of the communication quality and the possibility of congestion. However, building such high-reliability networks involves huge costs. Therefore, it is considered necessary to devise a network design that can realize continuity of communication between the master server and the edge-servers by suppressing sudden increases in path length, even if a failure occurs. In this paper, we formulate a network design problem and show that it is NP-hard. We also design a polynomial-time approximation algorithm for the case where the number of failed Links is constant, and we evaluated its performance in various actual network topologies.
S. Ramamurthy - One of the best experts on this subject based on the ideXlab platform.
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Survivable WDM mesh networks
Journal of Lightwave Technology, 2003Co-Authors: S. Ramamurthy, L. Sahasrabuddhe, Biswanath MukherjeeAbstract:In a wavelength-division-multiplexing (WDM) optical network, the failure of network elements (e.g., fiber Links and cross connects) may cause the failure of several optical channels, thereby leading to large data losses. This study examines different approaches to protect a mesh-based WDM optical network from such failures. These approaches are based on two survivability paradigms: 1) path Protection/restoration and 2) Link Protection/restoration. The study examines the wavelength capacity requirements, and routing and wavelength assignment of primary and backup paths for path and Link Protection and proposes distributed protocols for path and Link restoration. The study also examines the Protection-switching time and the restoration time for each of these schemes, and the susceptibility of these schemes to multiple Link failures. The numerical results obtained for a representative network topology with random traffic demands demonstrate that there is a tradeoff between the capacity utilization and the susceptibility to multiple Link failures. We find that, on one hand, path Protection provides significant capacity savings over Link Protection, and shared Protection provides significant savings over dedicated Protection; while on the other hand, path Protection is more susceptible to multiple Link failures than Link Protection, and shared Protection is more susceptible to multiple Link failures than dedicated Protection. We formulate a model of Protection-switching times for the different Protection schemes based on a fully distributed control network. We propose distributed control protocols for path and Link restoration. Numerical results obtained by simulating these protocols indicate that, for a representative network topology, path restoration has a better restoration efficiency than Link restoration, and Link restoration has a faster restoration time compared with path restoration.
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survivable wdm mesh networks part i Protection
International Conference on Computer Communications, 1999Co-Authors: S. Ramamurthy, Biswanath MukherjeeAbstract:This investigation considers optical networks which employ wavelength cross-connects that enable the establishment of wavelength-division-multiplexed (WDM) channels, between node-pairs. In such and other networks, the failure of a network element (e.g., fiber Link, cross-connect, etc.) may cause the failure of several optical channels, thereby leading to large data losses. This study examines different approaches to protect mesh based WDM optical networks from single-Link failures. These approaches are based on two basic survivability paradigms: (a) path Protection/restoration, and (b) Link Protection/restoration. In path- and Link-Protection schemes, backup paths and wavelengths are reserved in advance at the time of call setup. Path- and Link-restoration schemes are dynamic schemes in which backup paths are discovered (from the spare capacity in the network) upon the occurrence of a failure. In part 1 of this study presented in this paper, we formulated integer linear programs to determine the capacity requirements for the above Protection schemes for a static traffic demand.
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INFOCOM - Survivable WDM mesh networks. Part I-Protection
IEEE INFOCOM '99. Conference on Computer Communications. Proceedings. Eighteenth Annual Joint Conference of the IEEE Computer and Communications Socie, 1999Co-Authors: S. Ramamurthy, Biswanath MukherjeeAbstract:This investigation considers optical networks which employ wavelength cross-connects that enable the establishment of wavelength-division-multiplexed (WDM) channels, between node-pairs. In such and other networks, the failure of a network element (e.g., fiber Link, cross-connect, etc.) may cause the failure of several optical channels, thereby leading to large data losses. This study examines different approaches to protect mesh based WDM optical networks from single-Link failures. These approaches are based on two basic survivability paradigms: (a) path Protection/restoration, and (b) Link Protection/restoration. In path- and Link-Protection schemes, backup paths and wavelengths are reserved in advance at the time of call setup. Path- and Link-restoration schemes are dynamic schemes in which backup paths are discovered (from the spare capacity in the network) upon the occurrence of a failure. In part 1 of this study presented in this paper, we formulated integer linear programs to determine the capacity requirements for the above Protection schemes for a static traffic demand.