Multilayer flex-grid network planning

The traffic in metro and core networks is forecasted to grow in volume but also in dynamicity, and the inefficiency of WDM optical networks drove research efforts on flex-grid technologies. Flex-grid networks support variable spectrum connections as a way to increase spectral efficiency and support future transmission rates. In addition, the use of flexible transponders further increases the flexibility of such networks, bringing closer the optical and the IP layers. The joint planning and operation of both layers becomes crucial to reduce the capital and operational costs. To this end, in this paper we examine the planning problem of a multilayer (ML) flex-grid network from the perspective of capital expenditure taking into account modular IP/MPLS routers at the optical network edges along with tunable optical transponders. We propose a concise ILP formulation that jointly solves the ML planning problem. The formulation is quite generic and can be used for flex- and fixed-grid networks employing flexible or fixed transponders.