The Experts below are selected from a list of 819 Experts worldwide ranked by ideXlab platform
Lian-kuan Chen - One of the best experts on this subject based on the ideXlab platform.
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Novel network architectures for survivable WDM passive optical networks
2008 34th European Conference on Optical Communication, 2008Co-Authors: Calvin C. K. Chan, Lian-kuan ChenAbstract:In this paper, several considerations in designing survivable WDM-PONs will be discussed. Several feasible protection schemes and architectures for automatic traffic restoration upon any Fiber Cut in WDM-PONs will be reviewed.
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Novel network architectures for survivable WDM passive optical networks
2008 34th European Conference on Optical Communication, 2008Co-Authors: Calvin C. K. Chan, Lian-kuan ChenAbstract:As WDM-PON has been emerging to be the next generation optical access network, the issue of network survivability has recently aroused much attention. In this talk, several considerations in designing survivable WDM-PONs will be discussed. Besides, several feasible protection schemes and architectures for automatic traffic restoration upon any Fiber Cut in WDM-PONs will be reviewed.
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A novel centrally controlled protection scheme for traffic restoration in WDM passive optical networks
IEEE Photonics Technology Letters, 2005Co-Authors: Zhaoxin Wang, Chun-kit Chan, Lian-kuan ChenAbstract:We propose and experimentally demonstrate a novel centrally controlled protection scheme for arrayed waveguide grating-based bidirectional wavelength-division-multiplexing passive optical networks which can provide automatic traffic restoration against Fiber Cut between remote node and optical network unit. Compared with the previous structures, its requirements on the network resources are greatly reduced with negligible protection performance degradation.
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A self-protected architecture for wavelength-division-multiplexed passive optical networks
IEEE Photonics Technology Letters, 2003Co-Authors: Tsan-kim Chan, Chun-kit Chan, Lian-kuan Chen, Fei TongAbstract:We propose a novel network architecture for wavelength-division-multiplexed passive optical networks which can provide bidirectional 1:1 protection against any Fiber Cut between the remote node and the optical network units (ONUs). In case of such Fiber Cut, the affected ONU can still communicate with the optical line terminal by rerouting the wavelength channels via the adjacent ONU.
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Fiber-fault identification for branched access networks using a wavelength-sweeping monitoring source
IEEE Photonics Technology Letters, 1999Co-Authors: Chun-kit Chan, Lian-kuan Chen, F. Tong, Keang-po HoAbstract:We propose and experimentally demonstrate a new Fiber-fault identification scheme for optically amplified branched networks. The scheme makes use of Fiber Bragg gratings and an internally generated light source from erbium-doped Fiber amplifiers through an optical feedback loop, and no additional dedicated monitoring source is required. The monitoring technique invokes both frequency and time domain by sweeping the wavelength of the monitoring source. By combining with a conventional optical time-domain reflectometer technique, exact location in Fiber Cut in branched network can be identified readily.
Chun-kit Chan - One of the best experts on this subject based on the ideXlab platform.
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A novel centrally controlled protection scheme for traffic restoration in WDM passive optical networks
IEEE Photonics Technology Letters, 2005Co-Authors: Zhaoxin Wang, Chun-kit Chan, Lian-kuan ChenAbstract:We propose and experimentally demonstrate a novel centrally controlled protection scheme for arrayed waveguide grating-based bidirectional wavelength-division-multiplexing passive optical networks which can provide automatic traffic restoration against Fiber Cut between remote node and optical network unit. Compared with the previous structures, its requirements on the network resources are greatly reduced with negligible protection performance degradation.
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A novel bidirectional wavelength division multiplexed passive optical network with 1:1 protection
OFC 2003 Optical Fiber Communications Conference, 2003., 2003Co-Authors: T. J. Chan, Yuen-ching Ku, Chun-kit Chan, Fei TongAbstract:We propose a novel network architecture for WDM-PON which offers 1:1 protection capability. In case of any Fiber Cut between remote node and ONUs, the affected ONU can re-route the wavelength channels via the adjacent ONU.
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A self-protected architecture for wavelength-division-multiplexed passive optical networks
IEEE Photonics Technology Letters, 2003Co-Authors: Tsan-kim Chan, Chun-kit Chan, Lian-kuan Chen, Fei TongAbstract:We propose a novel network architecture for wavelength-division-multiplexed passive optical networks which can provide bidirectional 1:1 protection against any Fiber Cut between the remote node and the optical network units (ONUs). In case of such Fiber Cut, the affected ONU can still communicate with the optical line terminal by rerouting the wavelength channels via the adjacent ONU.
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Fiber-fault identification for branched access networks using a wavelength-sweeping monitoring source
IEEE Photonics Technology Letters, 1999Co-Authors: Chun-kit Chan, Lian-kuan Chen, F. Tong, Keang-po HoAbstract:We propose and experimentally demonstrate a new Fiber-fault identification scheme for optically amplified branched networks. The scheme makes use of Fiber Bragg gratings and an internally generated light source from erbium-doped Fiber amplifiers through an optical feedback loop, and no additional dedicated monitoring source is required. The monitoring technique invokes both frequency and time domain by sweeping the wavelength of the monitoring source. By combining with a conventional optical time-domain reflectometer technique, exact location in Fiber Cut in branched network can be identified readily.
Maurice Gagnaire - One of the best experts on this subject based on the ideXlab platform.
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A SDN-based network architecture for cloud resiliency
2015 12th Annual IEEE Consumer Communications and Networking Conference (CCNC), 2015Co-Authors: Antoine Fressancourt, Maurice GagnaireAbstract:In spite of their commercial success, Cloud services are still subject to two major weak points: data security and infrastructure resiliency. In this paper, we propose an original Cloud network architecture aiming at improving the resiliency of Cloud network infrastructures interconnecting remote data centers. The main originality of this architecture consists in exploiting the principles of Software Defined Networking (SDN) in order to adapt the rerouting strategies in case of network failure according to a set of requirements. In existing Cloud networks configurations, network recovery after a Fiber Cut is achieved by means of the usage of redundant bandwidth capacity preplanned through backup links. Such an approach has two drawbacks. First, it induces at a large scale a non-negligible additional cost for the Cloud Service Providers (CSP). Second, the pre-computation of the rerouting strategy may not be suited to the specific quality of service requirements of the various data flows that were transiting on the failing link. To prevent these two drawbacks, we propose that CSPs deploy their services in several redundant data centers and make sure that those data centers are properly interconnected via the Internet. For that purpose, we propose that a CSP may use the services of multiple (typically two) Internet Service Providers to interconnect its data centers via the Internet. In practice, we propose that a set of “routing inflection points” may form an overlay network exploiting a specific routing strategy. We propose that this overlay is coordinated by a Software Defined Networking-based centralized controller. Thus, such a CSP may choose the network path between two data centers the most suited to the underlying traffic QoS requirement. The proposed approach enables this CSP a certain independency from its network providers. In this paper, we present this new Cloud architecture. We outline how our approach mixes concepts taken from both SDN an- Segment Routing. Unlike the protection techniques used by existing CSPs, we explain how this approach can be used to implement fast rerouting strategy for inter-data center data exchanges.
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A fast and accurate meta-heuristic for failure localization based on the monitoring trail concept
Telecommunication Systems, 2013Co-Authors: Ahmed Haddad, Elias A. Doumith, Maurice GagnaireAbstract:Recent advances in WDM technology enable an optical Fiber to carry up to 200 wavelengths operating at 40 Gbps each. In such networks, service disruptions caused by network faults (e.g., Fiber Cut, amplifier dysfunction) may lead to high data losses. Therefore, it is mandatory for a network operator to be able to detect and localize such faults in the lowest possible delays. Fault detection and localization in meshed WDM networks have been deeply investigated in the literature. Numerous schemes, both exact and approximate, have been proposed to achieve fast and accurate failure localization. In this paper, we propose an original Meta-heuristic for Monitoring Trail Assignment (MeMoTA). We show through numerical results that MeMoTA provides monitoring solutions closer to optimal than existing heuristic approaches while ensuring an acceptable scalability.
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A novel meta-heuristic approach for optical monitoring-tree design in WDM networks
2012 16th International Conference on Optical Network Design and Modelling (ONDM), 2012Co-Authors: Elias A. Doumith, Sawsan Al Zahr, Maurice GagnaireAbstract:Thanks to recent advances in WDM technologies, an optical Fiber is capable to carry up to 200 wavelengths operating at 40 Gbps each. In such high speed networks, service disruptions caused by network failures (e.g., Fiber Cut, amplifier dysfunction) may lead to high data losses. A network operator should be able to promptly locate such failures, in order to perform fast restoration. Hence, an efficient fault detection and localization mechanism is mandatory for reliable network design. In previous work, we have introduced the concept of monitoring-trees (m-trees) to achieve fast link failure detection and localization. We have proposed an integer linear programming (ILP) approach for the design of an m-tree solution that minimizes the number of required optical monitors, while achieving unambiguous failure detection and localization. In this paper, we propose a novel approach, based on the well known simulated annealing meta-heuristic, for the m-tree design in WDM networks. Simulations conducted in this study show the same results as the ILP approach at much lower computation time. Our proposal can thus be applied to large-sized and very large-sized networks.
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ICUMT - A meta-heuristic approach for monitoring trail assignment in WDM optical networks
International Congress on Ultra Modern Telecommunications and Control Systems, 2010Co-Authors: Ahmed Haddad, Elias A. Doumith, Maurice GagnaireAbstract:Optical network survivability relies on automatic Fiber Cut detection. Cost-effective and unambiguous Fiber Cut localization remains an open problem for transparent optical networks. In this paper, we focus on out-of-band monitoring techniques based on the concept of monitoring trail (m-trail) recently proposed in the literature [1]. An m-trail-based solution guarantees the exact localization of any single link failure. Two approaches have been proposed for the design of m-trails: an exact Integer Linear Program formulation and a heuristic approach based on the Random Code Assignment-Random Code Swapping (RCA-RCS) concept. Numerical applications underline two drawbacks of these approaches. The former is not scalable in terms of computational complexity. The latter provides monitoring solutions that strongly depend on the choice of the initial conditions. Thus, the final solutions can be relatively far from the optimal in the case of large networks. We propose an original meta-heuristic approach called MEMOTA that overcomes these drawbacks. Numerical results show that MEMOTA provides near optimal solutions with much shorter computing delays than the ILP formulation. In addition, unlike RCA-RCS, MEMOTA is less sensitive to initial conditions.
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GLOBECOM - Monitoring-Tree: An Innovative Technique for Failure Localization in WDM Translucent Networks
2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010Co-Authors: Elias A. Doumith, Sawsan Al Zahr, Maurice GagnaireAbstract:Because of the very high optical Fiber's capacity, prompt and unambiguous Fiber Cut detection is mandatory to guarantee carriers' network survivability. In this matter, the monitoring-cycle and the monitoring-trail mechanisms have been proposed in the recent literature. In this paper, we propose the innovative concept of monitoring-tree that enables to reduce considerably the monitoring cost while keeping unambiguous single Fiber Cut detection and localization. We propose an ILP formulation aiming at mapping a monitoring-tree onto a mesh topology. Applied to real networks, we show that our approach outperforms its counterparts.
Fei Tong - One of the best experts on this subject based on the ideXlab platform.
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A novel bidirectional wavelength division multiplexed passive optical network with 1:1 protection
OFC 2003 Optical Fiber Communications Conference, 2003., 2003Co-Authors: T. J. Chan, Yuen-ching Ku, Chun-kit Chan, Fei TongAbstract:We propose a novel network architecture for WDM-PON which offers 1:1 protection capability. In case of any Fiber Cut between remote node and ONUs, the affected ONU can re-route the wavelength channels via the adjacent ONU.
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A self-protected architecture for wavelength-division-multiplexed passive optical networks
IEEE Photonics Technology Letters, 2003Co-Authors: Tsan-kim Chan, Chun-kit Chan, Lian-kuan Chen, Fei TongAbstract:We propose a novel network architecture for wavelength-division-multiplexed passive optical networks which can provide bidirectional 1:1 protection against any Fiber Cut between the remote node and the optical network units (ONUs). In case of such Fiber Cut, the affected ONU can still communicate with the optical line terminal by rerouting the wavelength channels via the adjacent ONU.
Byrav Ramamurthy - One of the best experts on this subject based on the ideXlab platform.
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Survivable traffic grooming in WDM mesh networks under SRLG constraints
IEEE International Conference on Communications 2005. ICC 2005. 2005, 2005Co-Authors: Byrav RamamurthyAbstract:Survivable traffic grooming (STG) is a promising approach to provide reliable and resource-efficient multi-granularity connection services in optical networks. In this paper, we study the static STG problem in WDM mesh networks employing path protection at the lightpath level. To make connections survivable under various failures such as Fiber Cut and duct Cut, we consider the general shared risk link group (SRLG) diverse routing constraints. In addition to providing the results from the integer linear programming (ILP) approach, we propose three efficient heuristics, namely separated grooming algorithm (SGA), integrated grooming algorithm (IGA) and tabu search grooming algorithm (TSGA). While SGA and IGA correspond to an overlay model and a peer model respectively, TSGA further improves SGA and IGA by incorporating the tabu search method. Numerical results show that the heuristics use much shorter running times to generate network throughputs close to those of the ILP formulations.
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Survivable traffic grooming with path protection at the connection level in WDM mesh networks
Journal of Lightwave Technology, 2005Co-Authors: Byrav RamamurthyAbstract:Survivable traffic grooming (STG) is a promising approach to provide reliable and resource-efficient multigranularity connection services in wavelength-division-multiplexing (WDM) optical networks. In this paper, we study the STG problem in WDM mesh optical networks employing path protection at the connection level. Both dedicated-protection and shared-protection schemes are considered. Given network resources, the objective of the STG problem is to maximize network throughput. To enable survivability under various kinds of single failures, such as Fiber Cut and duct Cut, we consider the general shared-risk-link-group (SRLG) diverse routing constraints. We first resort to the integer-linear-programming (ILP) approach to obtain optimal solutions. To address its high computational complexity, we then propose three efficient heuristics, namely separated survivable grooming algorithm (SSGA), integrated survivable grooming algorithm (ISGA), and tabu-search survivable grooming algorithm (TSGA). While SSGA and ISGA correspond to an overlay network model and a peer network model, respectively, TSGA further improves the grooming results from SSGA and ISGA by incorporating the effective tabu-search (TS) method. Numerical results show that the heuristics achieve comparable solutions to the ILP approach, which uses significantly longer running times than the heuristics.
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Survivable traffic grooming with path protection at the connection level in WDM mesh networks
First International Conference on Broadband Networks, 2004Co-Authors: Byrav RamamurthyAbstract:Survivable traffic grooming (STG) is a promising approach to provide reliable and resource-efficient multigranularity connection services in wavelength division multiplexing (WDM) optical networks. In this paper, we study the STG problem in WDM mesh optical networks employing path protection at the connection level. Both dedicated protection and shared protection schemes are considered. Given the network resources, the objective of the STG problem is to maximize network throughput. To enable survivability under various kinds of single failures such as Fiber Cut and duct Cut, we consider the general shared risk link group (SRLG) diverse routing constraints. We first resort to the integer linear programming (ILP) approach to obtain optimal solutions. To address its high computational complexity, we then propose three efficient heuristics, namely separated survivable grooming algorithm (SSGA), integrated survivable grooming algorithm (ISGA) and tabu search survivable grooming algorithm (TSGA). While SSGA and ISGA correspond to an overlay network model and a peer network model respectively, TSGA further improves the grooming results from SSGA and ISGA by incorporating the effective tabu search method. Numerical results show that the heuristics achieve comparable solutions to the ILP approach, which uses significantly longer running times than the heuristics.