Hardware reuse policies for fixed and flexible next-generation optical transport network architectures in multi-period scenarios

New technologies are emerging to make optical transport networks increasingly flexible and cost-effective. Transponder modules capable of rate adaptation and sliceability promise a scalable way to support the upcoming traffic growth. The deployment of these flexible modules on the line-side can be enhanced with a pay-as-you-grow approach also on the client-side, where capacity is provisioned on demand for maximum cost-efficiency. Bridging these two elements together with flexible client-to-line interconnection switch fabrics ties together the concept of a fully-flexible next-generation optical transport network. Such a high degree of configurability greatly expands the ability to automatically reuse equipment modules in multiple situations over the course of the network lifecycle. On the other hand, manual re-provisioning of available equipment is an alternative to improve resource reuse in otherwise rigid network designs based on fixed transponders and client-to-line interconnections. The policy each operator chooses regarding the level of manual reconfigurations it allows in its network to reuse idle hardware can have a lasting impact on the overall cost of deploying a transport infrastructure. This paper addresses, through a multi-period planning simulation, the effect of idle part handling on network deployment cost and resource efficiency. The analysis is conducted for multiple transport architectures, ranging from traditional transponders and muxponders to more flexible designs on both the client- and line-sides.