Survivable impairment-aware traffic grooming and regenerator placement with connection-level protection

In this paper, we address the problem of survivable traffic grooming and regenerator placement in optical wavelength division multiplexing (WDM) networks with impairment constraints. The working connections are protected end to end by provisioning bandwidth along a sequence of lightpaths through either a dedicated or a shared connection-level protection scheme. We propose an auxiliary-graph-based approach to address the placement of regenerators and grooming equipment for both working and backup connections in the network in order to minimize the total equipment cost. Simulation results show that the proposed algorithms outperform lightpath-level protection algorithms, in which each lightpath is protected separately. We also show the performance of connection-level protection under both dedicated and shared protection schemes in terms of the network cost, along with the effect of different cost models on equipment placement and performance for networks with different line rates. The restoration time of dedicated and shared connection-level protection is also investigated.