Cost and Power-Consumption Analysis for Power Profile Monitoring with Multiple Monitors per Link in Optical Networks

Network monitoring is essential to collect compre-hensive data on signal quality in optical networks. As deploying large amounts of monitoring equipment results in elevated cost and power consumption, novel low-cost monitoring methods are continuously being investigated. A new technique called Power Profile Monitoring (PPM) has recently gained traction thanks to its ability to monitor an entire lightpath using a single post-processing unit at the lightpath receiver. PPM does not require to deploy an individual monitor for each span, as in the traditional monitoring technique using Optical Time-Domain Reflectometer (OTDR). PPM and OTDR have different monitoring applications, which will be elaborated in our discussion, hence they can be considered either alternative or complementary techniques according to the targeted monitoring capabilities to be implemented in the network. In this work, we aim to quantify the cost and power consumption of PPM (using OTDR as a baseline reference), as this analysis can provide guidelines for the implementation and deployment of PPM. First, we discuss how PPM and OTDR monitors are deployed, and we formally state a new Optimized Monitoring Placement (OMP) problem for PPM. Solving the OMP problem allows to identify the minimum number of PPM monitors that guarantees that all links in the networks are monitored by at least n PPM monitors (note that using n > 1 allows for increased monitoring accuracy). We prove the NP-hardness of the OMP problem and formulate it using an Integer Linear Programming (ILP) model. Finally, we also devise a heuristic algorithm for the OMP problem to scale to larger topologies. Our numerical results, obtained on realistic topologies, suggest that the cost (power) of one PPM module should be lower than 2.6 times and 10.2 times that of one OTDR for nation-wide and continental-wide topology, respectively.