Infrastructure Costs in Dynamic Optical Networks

In this paper a cost model for the evaluation of the infrastructure costs of dynamic optical networks is provided. For an expected traffic demand, the cost model uses a bottom-up approach for the dimensioning of transponders and optical nodes, namely, reconfigurable optical add/drop multiplexers (ROADM). The infrastructure costs are calculated as the sum of the costs of ROADMs, transponders and optical amplifiers. The approach is applied to the calculation of the network costs for two ROADM implementations, namely, colorless and colorless & directionless. For selected network topologies, the results show that the lowest costs are obtained by colorless ROADMs. However, by this solution the network cannot automatically reroute traffic in case of link failures. This is overcome by adding the directionless property to colorless ROADMs. Although the resulting solution is more costly, it allows efficient utilization of network resources. In fact, a colorless & directionless network reduces the number of transponders needed to serve an expected traffic demand.