Routing and wavelength assignment for online real-time multicast connection setup is a difficult task due to the dynamic change of availabilities of wavelengths on links and the consideration of wavelength conversion ...Routing and wavelength assignment for online real-time multicast connection setup is a difficult task due to the dynamic change of availabilities of wavelengths on links and the consideration of wavelength conversion delay in WDM networks. This paper presents a distributed routing and wavelength assignment scheme for the setup of real-time multicast connections. It integrates routing and wavelength assignment as a single process, which greatly reduces the connection setup time. The proposed routing method is based on the Prim’s MST (Minimum Spanning Tree) algorithm and the K-restricted breadth-first search method, which can produce a sub-minimal cost tree under a given delay bound. The wave-length assignment uses the least-conversion and load balancing strategies. Simulation results show that the proposed algorithm is suitable for online multicast connection establishment in WDM networks.展开更多
In this paper, the wavelength-routed WDM network was analyzed for the dynamic case where the arrival of anycast requests was modeled by a state-dependent Poisson process. The equilibrium analysis was also given with t...In this paper, the wavelength-routed WDM network was analyzed for the dynamic case where the arrival of anycast requests was modeled by a state-dependent Poisson process. The equilibrium analysis was also given with the UWNC algorithm.展开更多
This paper classifies and surveys different approaches proposed for performance monitoring, in particular the optical signal-to-noise ratio (OSNR) monitoring, in transparent reconfigurable WDM networks. Some considera...This paper classifies and surveys different approaches proposed for performance monitoring, in particular the optical signal-to-noise ratio (OSNR) monitoring, in transparent reconfigurable WDM networks. Some considerations for future monitoring schemes are discussed.展开更多
To improve the network performance after traffic demand changes, reconfiguring the logical topology is necessary. We present an ILP algorithm to find out the least lightpath changes needed with guaranteed network perf...To improve the network performance after traffic demand changes, reconfiguring the logical topology is necessary. We present an ILP algorithm to find out the least lightpath changes needed with guaranteed network performance.展开更多
Crystal optics and fiber grating technology are two of the most important optical fiber device technologies. In this paper, we report several new devices developed in Accelink for WDM networks application.
Wavelength division multiplexing (WDM) has been becoming a promising solution to meet the rapidly growing demands on bandwidth. Multicast in WDM networks by employing free wavelength is an efficient approach to savi...Wavelength division multiplexing (WDM) has been becoming a promising solution to meet the rapidly growing demands on bandwidth. Multicast in WDM networks by employing free wavelength is an efficient approach to saving bandwidth and cost. However, the free wavelength may not identical between different hops in a multicast light-path, particularly in heavy load optical WDM networks. In order to implement multicast applications efficiently, a network coding (NC) technique was introduced into all-optical WDM multicast networks to solve wavelength collision problem between the multicast request and the unicast request. Compared with the wavelength conversion based optical multicast, the network coding based optical multicast can achieve better multicast performance with paying lower cost.展开更多
The problem of differentiated Multi-Layer Integrated Survivability (MLIS) in IP over WDM networks is studied, which is decomposed into three sub-problems: survivable strategies design (SSD), spare capacity dimensionin...The problem of differentiated Multi-Layer Integrated Survivability (MLIS) in IP over WDM networks is studied, which is decomposed into three sub-problems: survivable strategies design (SSD), spare capacity dimensioning (SCID), and dynamic survivable routing (DSR). A related work of network survivability in IP over WDM networks is firstly provided, and adaptive survivable strategies are also designed. A new Integrated Shared Pool (ISP) approach for SCD is then proposed, which is formulated by using integer-programming theory. Moreover, a novel survivable routing scheme called Differentiated Integrated Survivability Algorithm (DISA) for DSR is developed. Simulation results show that the proposed integrated survivability scheme performs much better than other solutions (e,g., 'highest layer recovery' and 'lowest layer recovery' schemes) in terms of traffic blocking ratio, spare resource requirement, and average traffic recovery ratio in IP over WDM networks.展开更多
In future high-capacity wavelength division multiplexed(WDM)optical networks,the failure of a network component such as a fiber link can lead to severe disruption in the networks’traffic.Hence,it is imperatively impo...In future high-capacity wavelength division multiplexed(WDM)optical networks,the failure of a network component such as a fiber link can lead to severe disruption in the networks’traffic.Hence,it is imperatively important to provide fast and full protection in WDM optical networks.In this paper,we propose a new approach,called shared preconfigured protection cycles(shared-p-cycles),for the design of survivable WDM networks.We develop an integer linear program(ILP)formulation to solve the problem of shared-p-cycles design for WDM networks with and without wavelength conversion.Numerical results show that the shared-p-cycles design is more efficient in the use of spare capacity and requires much less spare capacity than the conventional pcycles design.展开更多
In wavelength division multiplexing (WDM) networks without wavelengthconversion functionality, we convert the dynamic routing and wavelength assignment problem formulti-lightpath demands to the edge-disjoint paths pro...In wavelength division multiplexing (WDM) networks without wavelengthconversion functionality, we convert the dynamic routing and wavelength assignment problem formulti-lightpath demands to the edge-disjoint paths problem, and propose a new algorithm. Thecomputer simulations show that the proposed algorithm has better blocking probability performancethan a sequential algorithm, which first separates a multi-lightpath demand into mutilplesingle-lightpath demands, then uses the fixed-alternate routing-first fit wavelength assignment(AR-FF) algorithm for each single-lightpath demand.展开更多
Aiming at minimizing spare capacity for optical WDM networks, we propose a new heuristic algorithm for preconfigured protection cycle (p-cycle) design. Numerical results show that the spare capacity obtained by our ne...Aiming at minimizing spare capacity for optical WDM networks, we propose a new heuristic algorithm for preconfigured protection cycle (p-cycle) design. Numerical results show that the spare capacity obtained by our new algorithm is very close to the optimal solution.展开更多
This paper reviews the recent advances in multi-terabit long-haul transmission technologies for terrestrial optical networks. The use of high performance new fibres, low-noise Raman amplification, optimised modulation...This paper reviews the recent advances in multi-terabit long-haul transmission technologies for terrestrial optical networks. The use of high performance new fibres, low-noise Raman amplification, optimised modulation formats, and forward error correction is shown to be effective for capacity and distance expansion.展开更多
A novel model on dynamic resource allocation in the WDM optical networks is proposed, basing on the integrated considerations of the impacts of transmission impairments and service classification on dynamic resource a...A novel model on dynamic resource allocation in the WDM optical networks is proposed, basing on the integrated considerations of the impacts of transmission impairments and service classification on dynamic resource allocation in the optical layer. In this model, the priorities of optical connection requests are mapped into different thresholds of transmission impairments, and a uniform method which is adopted to evaluate the virtual wavelength path (VWP) candidates is defined. The Advanced Preferred Wavelength Sets Algorithm (A-PWS) and the heuristic Dynamic Min-Cost & Optical Virtual Wavelength Path Algorithm (DMC-OVWP) are presented addressing the routing and wavelength assignment (RWA) problem based on dynamic traffic and multi priorities in wavelength-routed optical networks. For a received optical connection request, DMC-OVWP is employed to calculate a list of the VWP candidates, and an appropriate VWP which matches the request's priority is picked up to establish the lightpath by analyzing the transmission qualities of the VWP candidates.展开更多
We have demonstrated a flexible twin open ring WDM network for metro applications. A pair of optical switches in the network keeps the fiber rings open to prevent signal circulation. Traffics are broadcast to every no...We have demonstrated a flexible twin open ring WDM network for metro applications. A pair of optical switches in the network keeps the fiber rings open to prevent signal circulation. Traffics are broadcast to every node and selected at the receiving side. Superior transmission and protection switching are proved.展开更多
In this paper, Optical Cross-Connection (OXC) induced crosstalk has been carefully analyzed for multiwavelength all-optical networks. Formulae are derived for calculating the crosstalk power of homowavelength crosstal...In this paper, Optical Cross-Connection (OXC) induced crosstalk has been carefully analyzed for multiwavelength all-optical networks. Formulae are derived for calculating the crosstalk power of homowavelength crosstalk and the total crosstalk at the receiver end. The results show that the optical switches induced crosstalk dominates over other crosstalk components of OXC, and the accumulated homowavelength crosstalk increases almost linearly with the increasing of the OXC number. At the receiver end , the heterowavelength crosstalk induced by the receiver optical filter has the same order as that of homowavelength crosstalk of OXC. The results of different optical components model are also discussed.展开更多
We demonstrate a bidirectional WDM self-healing ring network for hub/remote nodes with one fiber. In this network, self-healing can be achieved within 8 ms. The transmission capacity can be doubled in the operating st...We demonstrate a bidirectional WDM self-healing ring network for hub/remote nodes with one fiber. In this network, self-healing can be achieved within 8 ms. The transmission capacity can be doubled in the operating state.展开更多
The tremendous and consistent increase in the volume and heterogeneity of traffic has resulted in major innovations in the telecommunication networks.In regard to the optical networks,existing studies have shown that ...The tremendous and consistent increase in the volume and heterogeneity of traffic has resulted in major innovations in the telecommunication networks.In regard to the optical networks,existing studies have shown that by adopting a mixed line rate(MLR)strategy,the wavelength division multiplexed optical networks can cost-effectively respond to the diverse variety of traffic requirements which have heterogeneous service demands.Unlike existing studies which focus on various MLR network issues by considering deployment of the standard single mode fiber only within the network,in the current work,we investigate the signal quality deterioration due to the combined effects of dominant physical layer impairments for an MLR optical network conforming to the various ITU-T compliant fibers and also considering the optical frequency grid based on ITU-T Recommendation G.692.The main aim of our current study is to identify,for a given fiber,the modulation format configuration which provides the highest performance.We conduct extensive simulations on the considered MLR system using the obtained optimum channel spacing values between the single and mixed line rates.Our results show that the existence of 10 Gbit/s line rate has a detrimental effect on the 40 Gbit/s and/or 100 Gbit/s line rate;however,the 40 Gbit/s and/or 100 Gbit/s line rate’s effect on a 10 Gbit/s line rate is not so detrimental,as well as between the similar line rates.Overall,our results clearly show that choice of the line rate of both,the central channel and its adjacent channels,has a major effect on the MLR network performance.展开更多
An spatial division multiplexing/wavelength division multiplexing router is designed for applying in a fiber-optical wide area network. Our comparison shows various spans of the good SDM/WDM WAN using the SO A based r...An spatial division multiplexing/wavelength division multiplexing router is designed for applying in a fiber-optical wide area network. Our comparison shows various spans of the good SDM/WDM WAN using the SO A based router.展开更多
文摘Routing and wavelength assignment for online real-time multicast connection setup is a difficult task due to the dynamic change of availabilities of wavelengths on links and the consideration of wavelength conversion delay in WDM networks. This paper presents a distributed routing and wavelength assignment scheme for the setup of real-time multicast connections. It integrates routing and wavelength assignment as a single process, which greatly reduces the connection setup time. The proposed routing method is based on the Prim’s MST (Minimum Spanning Tree) algorithm and the K-restricted breadth-first search method, which can produce a sub-minimal cost tree under a given delay bound. The wave-length assignment uses the least-conversion and load balancing strategies. Simulation results show that the proposed algorithm is suitable for online multicast connection establishment in WDM networks.
文摘In this paper, the wavelength-routed WDM network was analyzed for the dynamic case where the arrival of anycast requests was modeled by a state-dependent Poisson process. The equilibrium analysis was also given with the UWNC algorithm.
文摘This paper classifies and surveys different approaches proposed for performance monitoring, in particular the optical signal-to-noise ratio (OSNR) monitoring, in transparent reconfigurable WDM networks. Some considerations for future monitoring schemes are discussed.
文摘To improve the network performance after traffic demand changes, reconfiguring the logical topology is necessary. We present an ILP algorithm to find out the least lightpath changes needed with guaranteed network performance.
文摘Crystal optics and fiber grating technology are two of the most important optical fiber device technologies. In this paper, we report several new devices developed in Accelink for WDM networks application.
基金supported by the Doctor Foundation of Shandong Province (BS2013DX032)the Youth Scholars Development Program of Shandong University of Technology
文摘Wavelength division multiplexing (WDM) has been becoming a promising solution to meet the rapidly growing demands on bandwidth. Multicast in WDM networks by employing free wavelength is an efficient approach to saving bandwidth and cost. However, the free wavelength may not identical between different hops in a multicast light-path, particularly in heavy load optical WDM networks. In order to implement multicast applications efficiently, a network coding (NC) technique was introduced into all-optical WDM multicast networks to solve wavelength collision problem between the multicast request and the unicast request. Compared with the wavelength conversion based optical multicast, the network coding based optical multicast can achieve better multicast performance with paying lower cost.
文摘The problem of differentiated Multi-Layer Integrated Survivability (MLIS) in IP over WDM networks is studied, which is decomposed into three sub-problems: survivable strategies design (SSD), spare capacity dimensioning (SCID), and dynamic survivable routing (DSR). A related work of network survivability in IP over WDM networks is firstly provided, and adaptive survivable strategies are also designed. A new Integrated Shared Pool (ISP) approach for SCD is then proposed, which is formulated by using integer-programming theory. Moreover, a novel survivable routing scheme called Differentiated Integrated Survivability Algorithm (DISA) for DSR is developed. Simulation results show that the proposed integrated survivability scheme performs much better than other solutions (e,g., 'highest layer recovery' and 'lowest layer recovery' schemes) in terms of traffic blocking ratio, spare resource requirement, and average traffic recovery ratio in IP over WDM networks.
基金supported by China Postdoctoral Science Foundation (Nos.20070420013,200801030)Open Fund of National Laboratory on Local Fiber-Optic Communication Networks&Advanced Optical Communication Systems,Peking University,China,Guangxi Science Foundation (No.0731003)Science Foundation of Guangxi University (No.X071032).
文摘In future high-capacity wavelength division multiplexed(WDM)optical networks,the failure of a network component such as a fiber link can lead to severe disruption in the networks’traffic.Hence,it is imperatively important to provide fast and full protection in WDM optical networks.In this paper,we propose a new approach,called shared preconfigured protection cycles(shared-p-cycles),for the design of survivable WDM networks.We develop an integer linear program(ILP)formulation to solve the problem of shared-p-cycles design for WDM networks with and without wavelength conversion.Numerical results show that the shared-p-cycles design is more efficient in the use of spare capacity and requires much less spare capacity than the conventional pcycles design.
基金Supported by the National High Technology Development 863 Program of China(2001AA122023)
文摘In wavelength division multiplexing (WDM) networks without wavelengthconversion functionality, we convert the dynamic routing and wavelength assignment problem formulti-lightpath demands to the edge-disjoint paths problem, and propose a new algorithm. Thecomputer simulations show that the proposed algorithm has better blocking probability performancethan a sequential algorithm, which first separates a multi-lightpath demand into mutilplesingle-lightpath demands, then uses the fixed-alternate routing-first fit wavelength assignment(AR-FF) algorithm for each single-lightpath demand.
文摘Aiming at minimizing spare capacity for optical WDM networks, we propose a new heuristic algorithm for preconfigured protection cycle (p-cycle) design. Numerical results show that the spare capacity obtained by our new algorithm is very close to the optimal solution.
文摘This paper reviews the recent advances in multi-terabit long-haul transmission technologies for terrestrial optical networks. The use of high performance new fibres, low-noise Raman amplification, optimised modulation formats, and forward error correction is shown to be effective for capacity and distance expansion.
基金supported in part by the National Natural Science Foundation of China(Grant No.60272048).
文摘A novel model on dynamic resource allocation in the WDM optical networks is proposed, basing on the integrated considerations of the impacts of transmission impairments and service classification on dynamic resource allocation in the optical layer. In this model, the priorities of optical connection requests are mapped into different thresholds of transmission impairments, and a uniform method which is adopted to evaluate the virtual wavelength path (VWP) candidates is defined. The Advanced Preferred Wavelength Sets Algorithm (A-PWS) and the heuristic Dynamic Min-Cost & Optical Virtual Wavelength Path Algorithm (DMC-OVWP) are presented addressing the routing and wavelength assignment (RWA) problem based on dynamic traffic and multi priorities in wavelength-routed optical networks. For a received optical connection request, DMC-OVWP is employed to calculate a list of the VWP candidates, and an appropriate VWP which matches the request's priority is picked up to establish the lightpath by analyzing the transmission qualities of the VWP candidates.
文摘We have demonstrated a flexible twin open ring WDM network for metro applications. A pair of optical switches in the network keeps the fiber rings open to prevent signal circulation. Traffics are broadcast to every node and selected at the receiving side. Superior transmission and protection switching are proved.
文摘In this paper, Optical Cross-Connection (OXC) induced crosstalk has been carefully analyzed for multiwavelength all-optical networks. Formulae are derived for calculating the crosstalk power of homowavelength crosstalk and the total crosstalk at the receiver end. The results show that the optical switches induced crosstalk dominates over other crosstalk components of OXC, and the accumulated homowavelength crosstalk increases almost linearly with the increasing of the OXC number. At the receiver end , the heterowavelength crosstalk induced by the receiver optical filter has the same order as that of homowavelength crosstalk of OXC. The results of different optical components model are also discussed.
文摘We demonstrate a bidirectional WDM self-healing ring network for hub/remote nodes with one fiber. In this network, self-healing can be achieved within 8 ms. The transmission capacity can be doubled in the operating state.
文摘The tremendous and consistent increase in the volume and heterogeneity of traffic has resulted in major innovations in the telecommunication networks.In regard to the optical networks,existing studies have shown that by adopting a mixed line rate(MLR)strategy,the wavelength division multiplexed optical networks can cost-effectively respond to the diverse variety of traffic requirements which have heterogeneous service demands.Unlike existing studies which focus on various MLR network issues by considering deployment of the standard single mode fiber only within the network,in the current work,we investigate the signal quality deterioration due to the combined effects of dominant physical layer impairments for an MLR optical network conforming to the various ITU-T compliant fibers and also considering the optical frequency grid based on ITU-T Recommendation G.692.The main aim of our current study is to identify,for a given fiber,the modulation format configuration which provides the highest performance.We conduct extensive simulations on the considered MLR system using the obtained optimum channel spacing values between the single and mixed line rates.Our results show that the existence of 10 Gbit/s line rate has a detrimental effect on the 40 Gbit/s and/or 100 Gbit/s line rate;however,the 40 Gbit/s and/or 100 Gbit/s line rate’s effect on a 10 Gbit/s line rate is not so detrimental,as well as between the similar line rates.Overall,our results clearly show that choice of the line rate of both,the central channel and its adjacent channels,has a major effect on the MLR network performance.
文摘An spatial division multiplexing/wavelength division multiplexing router is designed for applying in a fiber-optical wide area network. Our comparison shows various spans of the good SDM/WDM WAN using the SO A based router.