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Abstract-In this paper, we present a practical VNT (virtual network topology) reconfiguration method for large-scale IP and optical networks with traffic matrix estimation considerations. We newly introduce a partial VNT reconfiguration algorithm with multiple transition stages. By dividing the whole VNT transition sequence into multiple transitions, estimation errors are calibrated at each stage by using network state information of prior stages. Because estimation errors are mainly due to the fewer information in the estimated traffic matrix calculation, our approach tries to increase the constraint conditions for traffic matrix estimation by introducing partial reconfiguration, and to relax the impact of estimation errors by limiting the number of optical-paths reconfigured at each stage. We also investigate the effectiveness of our proposal through simulations and clarify the robustness against estimation errors by using partial reconfiguration.

Abstract-In this paper, we present a practical VNT (virtual network topology) reconfiguration method for large-scale IP and optical networks with traffic matrix estimation considerations. We newly introduce a partial VNT reconfiguration algorithm with multiple transition stages. By dividing the whole VNT transition sequence into multiple transitions, estimation errors are calibrated at each stage by using network state information of prior stages. Because estimation errors are mainly due to the fewer information in the estimated traffic matrix calculation, our approach tries to increase the constraint conditions for traffic matrix estimation by introducing partial reconfiguration, and to relax the impact of estimation errors by limiting the number of optical-paths reconfigured at each stage. We also investigate the effectiveness of our proposal through simulations and clarify the robustness against estimation errors by using partial reconfiguration.

The growth of the Internet and emerging application layer technologies causes numerous changes in network environments. Therefore, it becomes important to achieve adaptive methods of controlling networks in addition to optimizing their performance. To achieve an adaptive network control method, we focus on attractor selection, which models behaviors where biological systems adapt to unknown changes in their surrounding environments and recover their conditions. In this paper, we show the applicability of the attractor selection to the adaptive virtual network topology (VNT) control in IP over wavelength-routed WDM networks. The simulation results indicate that our VNT control method based on attractor selection quickly and adaptively responds to various changes in traffic demand.

IP Fast Reroute techniques have been proposed for achieving fast failure recovery in just a few milliseconds. The basic idea of IP Fast Reroute is to reduce recovery time after failure by precomputing backup routes. A multiple routing configurations (MRC) algorithm has been proposed for obtaining IP Fast Reroute. MRC prepares backup configurations, which are used for finding a detour route after failure. On the other hand, requiring too many backup configurations consumes more network resources. It is necessary to recover more traffic flows with fewer backup configurations to ensure scalability. We propose a new backup configuration-creation algorithm for maximizing traffic flows which are fast recovered as much as possible under a limited number of backup configurations. The basic idea is to construct a spanning tree excluding failure links with higher link-loads in each backup configuration. We show that our algorithm has more robust on actual large IP networks.