This paper investigates the wavelength efficiency of failure protection based on rerouting in wavelength-routed optical networks. In order to study the impacts of different traffic pattern over the efficiency, a param...This paper investigates the wavelength efficiency of failure protection based on rerouting in wavelength-routed optical networks. In order to study the impacts of different traffic pattern over the efficiency, a parameter, wavelength reusability ρ, is introduced as an evaluation criterion. Performance of different failure protection methods and the influence of different routing schemes over the performance are investigated. The routing and wavelength assignment problem involved in failure protection is formulated as integer linear programming problem, relevant heuristic optimization algorithms are also developed, numerical results are presented and discussed in detail.展开更多
According to previous studies, limited range wavelength conversion (LWC) can improve the performance of optical network. In this paper, the effects of FWM (Four Wave Mixing) and XGM (Cross-Gain Modulation) conversion ...According to previous studies, limited range wavelength conversion (LWC) can improve the performance of optical network. In this paper, the effects of FWM (Four Wave Mixing) and XGM (Cross-Gain Modulation) conversion are both examined. It is found that the performance difference between LWC and full conversion becomes quite remarkable with the increase in numbers of wavelengths per-link. So in order to improve the performance of optical network with limited conversion in the case of large number of wavelengths, three simple dynamic wavelength assignment algorithms (LUWC, FUWC and WSM) are proposed. Simulation results show that the algorithms greatly reduce the blocking probabilities of networks with LWC. Moreover, the algorithms require no global information of network.展开更多
The problem of routing logical links (lightpaths) on a physical topology of WDM networks in a way that the logical topology remains connected in the event of single physical link failure is called survivable routing. ...The problem of routing logical links (lightpaths) on a physical topology of WDM networks in a way that the logical topology remains connected in the event of single physical link failure is called survivable routing. This paper addresses the survivable routing problem with and without wavelength-continuity constraints by proposing a new Integer Linear Programming (ILP) algorithm, which is based on a simplified necessary and sufficient condition. Numerical results are given and discussed to show that survivable routing solutions of most logical topologies can be found by the algorithm of the authors. Furthermore, comparing with other similar methods, the above algorithm can find out a survivable solution in much shorter time, and it works especially well with sparse-connected logical topologies. The impact of wavelength-continuity constraints and the other factors that influence the probability to find out a survivable solution are also discussed in the paper.展开更多
文摘This paper investigates the wavelength efficiency of failure protection based on rerouting in wavelength-routed optical networks. In order to study the impacts of different traffic pattern over the efficiency, a parameter, wavelength reusability ρ, is introduced as an evaluation criterion. Performance of different failure protection methods and the influence of different routing schemes over the performance are investigated. The routing and wavelength assignment problem involved in failure protection is formulated as integer linear programming problem, relevant heuristic optimization algorithms are also developed, numerical results are presented and discussed in detail.
文摘According to previous studies, limited range wavelength conversion (LWC) can improve the performance of optical network. In this paper, the effects of FWM (Four Wave Mixing) and XGM (Cross-Gain Modulation) conversion are both examined. It is found that the performance difference between LWC and full conversion becomes quite remarkable with the increase in numbers of wavelengths per-link. So in order to improve the performance of optical network with limited conversion in the case of large number of wavelengths, three simple dynamic wavelength assignment algorithms (LUWC, FUWC and WSM) are proposed. Simulation results show that the algorithms greatly reduce the blocking probabilities of networks with LWC. Moreover, the algorithms require no global information of network.
文摘The problem of routing logical links (lightpaths) on a physical topology of WDM networks in a way that the logical topology remains connected in the event of single physical link failure is called survivable routing. This paper addresses the survivable routing problem with and without wavelength-continuity constraints by proposing a new Integer Linear Programming (ILP) algorithm, which is based on a simplified necessary and sufficient condition. Numerical results are given and discussed to show that survivable routing solutions of most logical topologies can be found by the algorithm of the authors. Furthermore, comparing with other similar methods, the above algorithm can find out a survivable solution in much shorter time, and it works especially well with sparse-connected logical topologies. The impact of wavelength-continuity constraints and the other factors that influence the probability to find out a survivable solution are also discussed in the paper.
