Description
The Performance Measurement Function (PMF) is a core component within the 3GPP management architecture, specifically defined within the context of the 5G Core Network and its service-based interfaces. It operates as a producer of performance measurement data, collecting raw metrics from network functions (NFs) such as the Access and Mobility Management Function (AMF), Session Management Function (SMF), and User Plane Function (UPF). The PMF processes this data, which can include counters for successful procedures, failure rates, latency measurements, and resource utilization, transforming it into structured performance reports. These reports are then made available to consumer functions, primarily the Network Data Analytics Function (NWDAF) or external Operations, Administration, and Maintenance (OAM) systems, via standardized service-based interfaces like Npmf.
Architecturally, the PMF is defined to support both immediate and aggregated reporting. For immediate reporting, it can provide near-real-time performance data upon request. For aggregated reporting, it collects data over defined measurement periods and generates consolidated reports. The function handles measurement jobs, which are configurations specifying what to measure, from which NF, and the reporting format. It ensures data consistency and alignment with 3GPP-specified measurement types and formats, enabling standardized analytics across multi-vendor networks.
Its role is integral to closed-loop automation and network intelligence. By providing a centralized, standardized mechanism for performance data collection, the PMF feeds the analytics engines that drive network optimization, predictive maintenance, and dynamic resource allocation. It abstracts the complexity of raw data collection from individual NFs, offering a unified service for performance management. This supports key 5G goals like network slicing, where per-slice performance monitoring is essential for Service Level Agreement (SLA) assurance.
Purpose & Motivation
The PMF was introduced to address the challenges of performance management in the 5G service-based architecture (SBA). Previous generations relied on more rigid, element-manager-centric approaches where performance data collection was often vendor-specific and tightly coupled to network elements. This made centralized, cross-domain analytics and automation difficult. The 5G SBA, with its decoupled, cloud-native functions, required a new paradigm for observability.
The primary motivation was to create a standardized, scalable, and flexible function dedicated to performance data exposure. This enables network analytics and OAM systems to consume performance data in a consistent way, regardless of the underlying NF vendor. It solves the problem of data silos and heterogeneous collection methods, which were barriers to implementing advanced, AI-driven network automation and assurance for complex 5G use cases like network slicing and ultra-reliable low-latency communication (URLLC).
By defining the PMF, 3GPP provided a foundational enabler for the Management Data Analytics Service (MDAS) and the NWDAF ecosystem. It allows the network to self-monitor and self-optimize based on actual performance data, moving from reactive to proactive and predictive network management. This is critical for meeting the diverse and stringent performance requirements of 5G services.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (378 CRs across 6 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the Performance Measurement Function (PMF) was newly introduced to enable UE and UPF to exchange access performance measurements for Multi-Access PDU Sessions, specifically for procedures like Round-Trip Time (RTT) and Packet Loss Ratio (PLR) measurement. Key introductions included the support for measurements over QoS flows of non-default QoS rules, contingent on UE capability, and the transport of PMF protocol messages via UDP for IP-based sessions or Ethernet frames for Ethernet PDU sessions. This release also provided clarifications and corrections for measurement parameters, report types, and the precise definition of measurement start points and interfaces.
- Remove the redundant measurement of end-to-end latency KPI TS 28.552CR0002
- Correction of the Packet loss measurements TS 28.552CR0024
- Clarification of volume-based measurement report from UP to CP TS 29.244CR0093
- Essential correction on the start point of time based measurement TS 29.244CR0203
- Parameters for Performance Measurement TS 29.244CR0244
- Accurate Interface Type for Supporting Performance Measurement TS 29.244CR0243
In Release 16, the PMF was enhanced to support performance measurements on QoS flows of non-default QoS rules, not just the default QoS flow, based on a new UE capability indication. Furthermore, the SMF gained the ability to dynamically update the list of QoS flows used for measurements via Measurement Assistance Information (MAI), and detailed PMF protocol procedures were specified for both IPv4/IPv6 and Ethernet PDU session types.
- Add PDU Session Resource setup related measurements for gNB TS 28.552CR0004
- Add inter-gNB handover related measurements TS 28.552CR0005
- Add use case and definitions of TB related measurements TS 28.552CR0011
- Add PDU session modification related measurements for SMF TS 28.552CR0017
- Add PDU session release related measurements for SMF TS 28.552CR0018
- Add N4 Session Establishment related measurements for UPF TS 28.552CR0019
+ 124 more changes
In Release 17, the PMF was enhanced to support access performance measurements on QoS flows of non-default QoS rules, requiring the UE to indicate a specific "access performance measurements per QoS flow" capability. The SMF can then provide Measurement Assistance Information (MAI) containing a list of these specific QoS flows for measurement, and PMF protocol messages are transported over these designated flows using specified UDP ports.
- Add target QoS flow capability for access performance measurement TS 24.501CR3248
- Movement of "Distribution of Normally Released Call (5QI 1 QoS Flow) Duration" and "Distribution of Abnormally Released Call (5QI 1 QoS Flow) Duration" measurements to chapter 5.1.1.24. TS 28.552CR0243
- Add PLMN granularity for UE throughput measurements TS 28.552CR0244
- Add RRC establishment failure measurements TS 28.552CR0245
- Add measurements on network slice selection TS 28.552CR0249
- Add measurements on NSSAI availability service TS 28.552CR0250
+ 66 more changes
In Release 18, the PMF was enhanced to support performance measurements over QoS flows of non-default QoS rules, enabled by a new UE capability indication and corresponding updates to the Measurement Assistance Information (MAI). This allows for more granular traffic monitoring, and the release also introduced specific measurements for Multi-Access PDU (MA PDU) session creation related to ATSSS. Furthermore, the protocol procedures were detailed for transporting PMF messages over these non-default QoS flows using specified UDP ports for both 3GPP and non-3GPP accesses.
- Measurement assistance information TS 24.193CR0106
- Add use case of remote interference related performance measurement TS 28.552CR0375
- Add the per SSB RSRQ and SINR measurements TS 28.552CR0380
- Add measurements for UE throughput of Dedicated BWP TS 28.552CR0381
- Add a EAS discovery failure measurement TS 28.552CR0383
- New measurement Mean interruption time interval for 5QI 1 QoS Flow released due to double NG (double UE context). TS 28.552CR0385
+ 82 more changes
In Release 19, the Performance Measurement Function (PMF) was enhanced with new measurements for Multi-Access PDU Session (MA PDU Session) release and network-initiated Packet Loss Ratio (PLR) specifically for ATSSS, alongside new capabilities for performing measurements over QoS flows of non-default QoS rules based on UE capability. Additionally, Release 19 introduced new performance measurements for Small Data Transmission, the distribution of time intervals for L1/L2 Triggered Mobility, and monitoring of Sub-Optimal Handovers. These additions expanded the PMF's role in providing granular, access-specific performance data to support advanced traffic steering and network optimization.
- Rel-19 CR TS 28.552 New measurements on TA acquisition requests for candidate LTM cells TS 28.552CR0528
- Add use case and measurements related to member UE selection assistance to AF TS 28.552CR0534
- Add use case and measurements related to NEF analytics exposure to AF TS 28.552CR0535
- Rel-19 CR TS 28.552 Add MA PDU session release measurement for ATSSS TS 28.552CR0551
- Rel-19 CR TS 28.552 Add new measurements for DL ITI Time Domain Proportion TS 28.552CR0554
- Rel-19 CR 28.552 Add measurement for DL packet loss on Uu with delay threshold in RAN TS 28.552CR0555
+ 61 more changes
In Release 20, the PMF (Performance Measurement Function) was enhanced to support measurements over QoS flows of non-default QoS rules, based on a new UE capability indication for "access performance measurements per QoS flow." This allowed the SMF to provide Measurement Assistance Information (MAI) specifying a list of QoS flows for RTT or PLR measurements, extending beyond the previous limitation to the default QoS rule. Additionally, protocol procedures were specified for transporting PMF protocol messages over these non-default QoS flows for IPv4, IPv6, IPv4v6, and Ethernet PDU session types.
- Rel-20 CR TS 28.552 Aggregated Performance Measurement TS 28.552CR0715
- Rel-20 CR 28.552 Add a new measurement related to the number of roaming data collection service subscriptions received by RE-NWDAF TS 28.552CR0717
- Rel-20 CR 28.552 Add a new measurement related to the number of roaming data collection service notifications generated by RE-NWDAF TS 28.552CR0718
- Rel-20 CR 28.552 Add new measurements related to the number of successful and failed roaming data collection service subscriptions received by RE-NWDAF TS 28.552CR0719
- Rel-20 CR 28.552 Add a new measurement related to the time consumed by the RE-NWDAF to provide roaming data collection service TS 28.552CR0720
- Rel-20 CR TS 28.552 Add UE Address Information Retrieval for UPF event exposure measurement TS 28.552CR0732
+ 9 more changes
Explore further
Broader topics and technologies where PMF plays a role.
Defining Specifications
3GPP specifications that define or reference PMF, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 24.193 vj50 | ATSSS Procedures Specification | Rel-19 |
| TS 24.501 vj50 | 5G NAS Protocols Specification | Rel-19 |
| TS 28.552 vk10 | 5G Performance Management Measurements | Rel-20 |
| TS 29.244 vj40 | PFCP Specification for Control/User Plane Separation | Rel-19 |