On the Impact of Deploying Optical Transport Networks Using Disaggregated Line Systems

Based on fundamental software-defined networking principles, disaggregated solutions have recently been proposed for optical transport networks. The first solution of such type takes the form of disaggregated line systems, which allow network operators to build networks using add/drop multiplexers from multiple vendors. In addition, these line systems allow any specification-compliant optical transponder to be freely connected, independent of their manufacturer. By removing the single-vendor dependency from line systems, traditional business models, based on vertically integrated solutions, are challenged and need to be rethought. Furthermore, competition between vendors is expected to increase, leading to higher innovation and differentiation. However, the development of interoperable line systems sharing a common set of specifications and capabilities may only be able to deliver suboptimal optical transmission performances when compared with proprietary solutions where line systems are fine-tuned. Hence, this paper evaluates the routing performance between disaggregated and proprietary optical line systems. Network simulations are carried out considering two different topologies with single- and multidomain proprietary deployments. The results obtained show that while proprietary line systems keep the capability of achieving the best optical performance, disaggregated solutions cannot be ignored since they have the potential to reduce the optical–electrical–optical interface count with respect to multivendor deployments while still guaranteeing minimal demand blocking.