Performance Metric

Description

Performance metric is an umbrella term introduced in 3GPP Release 19 to collectively refer to performance measurements and Key Performance Indicators (KPIs) as defined in management specifications such as TS 28.622 and TS 32.401. In the 3GPP management architecture, performance management (PM) is a functional area that collects, aggregates, and reports data about the behavior of network elements, network functions, and services. A performance metric is the fundamental unit of this data: a quantifiable measure that reflects some aspect of performance, such as throughput, latency, error rate, or resource utilization.

The term encompasses two related but distinct concepts. Performance measurements are raw or minimally processed counts and gauges collected at the network element or network function level. Examples include the number of successful handovers, the number of dropped calls, or the average CPU utilization of a virtualized network function. KPIs, on the other hand, are typically derived from one or more measurements and are defined to assess the fulfillment of a specific requirement or objective, often from an end-user or service perspective. For example, a KPI might be the call setup success rate, which is computed from several measurements. By using the umbrella term performance metric, 3GPP avoids ambiguity when referring to both categories collectively.

In the 3GPP management framework, performance metrics are defined in TS 28.552 for 5G core and TS 28.554 for 5G end-to-end KPIs, among others. TS 32.401 provides the general performance management concept and requirements, including the definition of measurement jobs, collection periods, and reporting mechanisms. TS 28.622 is the generic network resource model (NRM) for 5G management, which includes performance metric definitions as attributes or notifications. The metrics are typically structured with a name, a unit, a collection method, and a set of associated dimensions (e.g., network slice, PLMN, QoS flow).

Performance metrics are used for multiple purposes: network optimization, fault management, capacity planning, and service assurance. They feed into closed-loop automation, where analytics functions (e.g., NWDAF) consume them to detect anomalies, predict trends, and trigger corrective actions. They are also essential for verifying Service Level Agreements (SLAs) and for regulatory reporting. The introduction of the umbrella term in Rel-19 reflects the growing complexity of 5G and beyond, where performance data spans multiple domains (RAN, core, transport, cloud) and must be harmonized across standards.

From an implementation perspective, performance metrics are often exposed via the management services defined in TS 28.532 (generic management services) and TS 28.550 (performance assurance). These services allow a management system to create measurement jobs, subscribe to notifications, and retrieve performance data. The metrics can be aggregated over time and space, and they can be filtered by various dimensions. The Rel-19 definition emphasizes that the term is a collective noun, not a specific measurement, which helps in writing requirements that apply to both measurements and KPIs without listing them separately.

Purpose & Motivation

The term Performance metric was introduced in 3GPP Release 19 to provide a clear, unified vocabulary for the management community. Prior to this, specifications often referred separately to 'performance measurements' and 'KPIs', which led to verbose and sometimes inconsistent phrasing. As 5G networks became more complex, with network slicing, virtualization, and multi-vendor environments, the need for a common umbrella term became evident. It allows requirements, interfaces, and data models to be written generically, covering both raw measurements and derived indicators.

The motivation also stems from the convergence of management and analytics. In 5G, performance data is not only used for traditional OAM but also for automation and assurance. By defining a single term, 3GPP facilitates the integration of performance management with other management functions such as fault management, configuration management, and intent-driven management. It also helps align with external standards bodies like TM Forum, which use similar umbrella concepts.

Historically, performance management in 3GPP has evolved from simple counters in 2G/3G to sophisticated, service-aware metrics in 5G. The Rel-19 definition is a natural progression, acknowledging that the boundary between measurements and KPIs is often blurred and that both are essential for assessing network health. The term is expected to be used in future releases as networks move toward 6G, where performance metrics will be even more diverse and dynamic.