Conference Paper

This paper analyzes how the next-generation of coherent optical interfaces for transport networks, based either on pluggable or high-end transponder modules, perform when required to provide traditional layer-0 protection/restoration mechanisms used in these scenarios. While the typical trade-off between these different devices lies in the capacity and reach vs. cost/complexity, survivability methods add further dimensions to the problem. Specifically, line-side protection methods have more stringent performance requirements due to the need to support both the working and protection paths with the same channel format. Optical restoration allows both backup spectrum and regenerators to be shared, which coupled to a much wider array of possible transmission formats leads to nontrivial design solutions for a given planning instance. In this analysis, we leverage a thorough optical performance characterization of pluggable and high-end interfaces, accounting for various realistic impairments, and combine it with an Integer Linear Programming (ILP) model that optimizes optical interface count in network designs with both line-side path protection and shared restoration. The results highlight, for different topology and traffic requirements, how deploying optical protection benefits from having more granular channel formats to choose from with high-end coherent. Optical restoration with backup regenerator placement optimized for sharing is also shown to be critical in making pluggable interfaces more competitive in larger topologies.