  The metrics play increasingly fundamental role in the design, development,
deployment and operation of telecommunication systems. Despite their
importance, the studies of metrics are usually limited to a narrow area or a
well-defined objective. Our study aims to more broadly survey the metrics that
are commonly used for analyzing, developing and managing telecommunication
networks in order to facilitate understanding of the current metrics landscape.
The metrics are simple abstractions of systems, and they directly influence how
the systems are perceived by different stakeholders. However, defining and
using metrics for telecommunication systems with ever increasing complexity is
a complicated matter which has not been so far systematically and
comprehensively considered in the literature. The common metrics sources are
identified, and how the metrics are used and selected is discussed. The most
commonly used metrics for telecommunication systems are categorized and
presented as energy and power metrics, quality-of-service metrics,
quality-of-experience metrics, security metrics, and reliability and resilience
metrics. Finally, the research directions and recommendations how the metrics
can evolve, and be defined and used more effectively are outlined.
