This report presents a comprehensive, in-depth analysis of the existing standards and metrics, exploring their historical context, methodologies, strengths, and inherent limitations. It meticulously identifies and dissects the critical challenges in achieving metric harmonization, delving into definitional inconsistencies, pervasive boundary conflicts, the complexities introduced by multi-tenancy and virtualization, challenges related to data quality and accessibility, and the difficulties of comparing KPIs across vastly different technological layers. Building upon this foundational analysis and grounded in the specific requirements of the IOWN Global Forum ecosystem—including All-Photonics Network (APN) and Data-Centric Infrastructure (DCI)—this report proposes a Unified Metric Framework.