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
To maximize the aggregate user utility in networks with both multirate multicast and unicast traffic, a unified convex program formulation of the problem is used to integrate multicast and unicast sessions into a comm...To maximize the aggregate user utility in networks with both multirate multicast and unicast traffic, a unified convex program formulation of the problem is used to integrate multicast and unicast sessions into a common framework, which also takes into account the heterogeneity of multicast receivers. By applying a penalty function approach, a heuristic rate control algorithm is derived. In the distributed implementation of the algorithm in IP networks, core routers employ Random Early Detection (RED) to mark packets in the case of congestion; end-users analyze congestion feedback information and update their rates to calculated optimal values. With an appropriate choice of utility functions and parameters, multicast and unicast sessions can share network resources in the proportional fair manner. Simulation results prove the algorithm's effectiveness. Study is also done on the effect of bandwidth discretization density upon resource allocation fairness in a layered multicast scenario.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To maximize the aggregate user utility in networks with both multirate multicast and unicast traffic, a unified convex program formulation of the problem is used to integrate multicast and unicast sessions into a common framework, which also takes into account the heterogeneity of multicast receivers. By applying a penalty function approach, a heuristic rate control algorithm is derived. In the distributed implementation of the algorithm in IP networks, core routers employ Random Early Detection (RED) to mark packets in the case of congestion; end-users analyze congestion feedback information and update their rates to calculated optimal values. With an appropriate choice of utility functions and parameters, multicast and unicast sessions can share network resources in the proportional fair manner. Simulation results prove the algorithm's effectiveness. Study is also done on the effect of bandwidth discretization density upon resource allocation fairness in a layered multicast scenario.
