A cost comparison of survivable subwavelength switching optical metro networks

In this paper, we compare the cost of the survivable optical transport solutions with subwavelength switching granularity. The focus is on Time-Domain Wavelength Interleaved Network (TWIN) and Packet Optical Add/Drop Multiplexer (POADM) network. Both technologies exploit optical slot switching: TWIN on a physical mesh topology, and POADM on a physical ring. The cost model accounts for the node components, the transponder cost and the cost of wavelength use per km of fiber. For the first time, a single network dimensioning model supporting protection is proposed for these metro technologies. The network planning solution is based on linear programming, and addresses the routing and wavelength assignment problem (RWA) and the optimal scheduler calculation. We consider dedicated protection, which consist in doubling the capacity of each operational connection network and shared protection, in which the protection capacity is potentially shared between multiple backup flows. By running the linear programming optimization we study the impact of different protection models on the cost of networks in different configurations and identify the scenarios for which each of the technologies is best suited.