Cross-layer optimization: Network cost vs. physical layer margins

Transmissions in optical networks are typically over-provisioned with respect to their capacity but also their physical layer performance: to account for physical layer interference and aging effects, worst-case assumptions and gross margins are used, resulting in low network efficiency and high network cost. Using realistic assumptions we evaluate the network cost gains that can be obtained by establishing connections with just enough physical layer performance on the first day of a flexible network operation.