Disaggregated OTN-over-WDM vs. Private Line Emulation based IP-over-WDM Core Networks: A Techno-Economic Comparison

Over the last two decades, Optical Transport Network (OTN) technology has been a crucial enabler of the core network by efficiently switching and multiplexing traffic with quality-of-service guarantees. Despite their high costs, core network architectures based on traditional monolithic OTN solutions still dominate due to their robustness and performance. Nevertheless, with the increase in high-speed services and the adoption of 400 Gb/s interfaces, novel architectures are needed to fully exploit the transmission capacity of the underlying wavelength division multiplexed (WDM) optical system. In this regard, this paper conducts a techno-economic study that investigates two emerging architectures: disaggregated OTN-over-WDM and Private Line Emulation (PLE)-based IP-over-WDM. They differ in the mechanisms applied to serve packet and circuit-switched services over a common WDM network. Disaggregated OTN-over-WDM replaces monolithic OTN fabrics with white-box Ethernet devices that interwork with IP routers and WDM optical switches. In contrast, PLE-based IP-over-WDM emulates private lines to enable circuit-switched services over IP infrastructures. Both architectures are compared against the standard monolithic OTN-over-WDM solution. Compared to this baseline solution, the results show that disaggregated OTN-over-WDM can achieve cost savings of up to 39%, while the PLE-based architecture can incur cost increments of up to 113%.