Description
Flow Based bearer Charging (FBC) is an architectural framework within the 3GPP Packet Switched (PS) domain that enables charging based on the detection and measurement of individual IP flows or Service Data Flows (SDFs). It moves beyond bearer-level charging (where all traffic on a PDP context is charged uniformly) to a more granular model. The core network nodes, specifically the Gateway GPRS Support Node (GGSN) in GPRS/UMTS or the Packet Data Network Gateway (P-GW) in EPS, are enhanced with Traffic Plane Functionalities that include Deep Packet Inspection (DPI) and flow classification capabilities. These gateways identify individual flows based on packet filters defined by policy rules, typically provided by the Policy and Charging Rules Function (PCRF).
The charging process works by associating each detected SDF with a specific Charging Key. The gateway then measures parameters for that flow, such as volume of data uplink/downlink, duration, or specific events. This usage data is formatted into Charging Data Records (CDRs) or formatted for online charging via the Gy reference point. The records are sent to the Charging Data Function (CDF) for offline charging or to the Online Charging System (OCS) via the Gy interface for real-time credit control. A single bearer (PDP context or EPS bearer) can thus contain multiple, separately charged SDFs. For example, a user's default bearer might carry a basic internet flow charged at one rate, a video streaming flow charged at a premium rate, and a zero-rated messaging app flow.
FBC is integral to the Policy and Charging Control (PCC) architecture defined in 3GPP. The PCRF uses the Sp (or Gx) interface to provision the gateway with Policy and Charging Control (PCC) rules. Each PCC rule contains the flow filters for identifying an SDF, the associated Charging Key, and other charging characteristics (e.g., whether charging is online or offline, rating group). This tight integration allows for dynamic, service-driven charging. The architecture supports both offline and online charging models, enabling prepaid and postpaid billing scenarios with high granularity. FBC is fundamental to implementing sophisticated service plans like tiered data access, sponsored data, and quality-of-service-based billing.
Purpose & Motivation
FBC was introduced to address the limitations of bearer-level charging in the face of evolving mobile data services. Early GPRS/UMTS networks charged based on the aggregate data volume on a PDP context, which treated all internet traffic equally. This model became inadequate as operators launched diverse services like VoIP, video streaming, and partner content, each requiring different billing models (e.g., per-minute, premium data buckets, or content-provider sponsored data). FBC was created to enable service-aware charging.
The primary motivation was to allow operators to monetize network services more flexibly and create new revenue streams. It solved the problem of not being able to distinguish between different types of traffic flowing through the same IP connection for billing purposes. By enabling charging per IP flow, operators could implement differentiated pricing, zero-rating, and service-specific promotions. Furthermore, it provided the technical foundation for coupling charging with quality of service (QoS), allowing operators to charge a premium for guaranteed bit-rate services. FBC, as part of the broader PCC framework, was a key enabler for the transition from simple data access to rich, billable service offerings in 3G and 4G networks, directly supporting business models like two-sided markets where content providers could pay for user data consumption.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (239 CRs across 6 releases). Complements the general historical overview above with the evidence-based evolution of this function.
Studied in Rel-6, normative work from Rel-15.
In Release 15, the FBC function was enhanced to support offline charging for the eFMSS (enhanced Fixed Mobile Substitution Service) and its bindings within the EPC, including charging enhancements on the TDF (Traffic Detection Function). Furthermore, Release 15 introduced charging support for secondary RAT (Radio Access Technology) usage and added a new CDR parameter for WLAN-based ProSe direct discovery.
- Charging enhancement for eFMSS TS 32.251CR0498
- Bindings of eFMSS for EPC offline charging TS 32.251CR0500
- Charging enhancement on TDF for eFMSS TS 32.251CR0501
- Support for secondary RAT in offline charging TS 32.251CR0502
- Charging enhancement for eFMSS TS 32.298CR0643
- Add CDR parameter for WLAN-based ProSe direct discovery TS 32.298CR0654
+ 18 more changes
In Release 16, key enhancements were made to Flow Based Charging (FBC) by introducing comprehensive support for offline-only charging. Specifically, the release added offline-only charging capabilities for the SMF, for QoS flow-based charging, and for various triggers, while also defining new offline charging service procedures and detailed message formats. Furthermore, it expanded the architecture by defining charging requirements, principles, and information for the I-SMF (Intermediate SMF) to support its role in 5G data connectivity.
- Introduce description of volume based charging for VoLTE in PS TS 32.251CR0514
- Add offline only charging TS 32.255CR0035
- Add offline only charging for SMF TS 32.255CR0036
- Add offline only charging CDR generation TS 32.255CR0038
- Add description of charging information for offline only charging TS 32.255CR0039
- Add offline only charging for flow based charging TS 32.255CR0040
+ 41 more changes
In Release 17, the FBC function was enhanced to introduce charging support for new service types, specifically adding charging principles, requirements, and information for URLLC (Ultra-Reliable Low Latency Communication) services and 5G LAN services. It also introduced charging enhancements for 5GS CIoT (Cellular Internet of Things) across various procedures, including home-routed roaming. Furthermore, the release added specific capabilities for URLLC, such as quota management and usage reporting, within the flow-based charging architecture.
- Add URLLC Charging Requirement TS 32.255CR0254
- Add Highly reliable URLLC services Charging TS 32.255CR0255
- Add Charging Principle for Usage Reporting TS 32.255CR0263
- Add PDU Modification and Release Message flow for URLLC Charging TS 32.255CR0275
- Add the Quota Management for URLLC Charging TS 32.255CR0276
- Add the Usage Reporting for URLLC Charging TS 32.255CR0277
+ 52 more changes
In Release 18, the FBC function was enhanced to introduce charging support for new 5G capabilities, specifically for 5G Multicast/Broadcast Services (5MBS) with new architecture, principles, and procedures. It also expanded to support charging for network slicing in roaming scenarios, for Standalone Non-Public Networks (SNPN), and for connectivity via satellite access, including the satellite backhaul. Furthermore, new charging principles were added for volume-based charging on the IMS data channel and for Time-Sensitive Communication (TSC) traffic.
- Add Identifier of SNPN for 5G data connectivity charging TS 32.255CR0418
- Slice-aware charging for Roaming partners TS 32.255CR0422
- Add charging principle of volume-based charging for IMS data channel TS 32.255CR0428
- Support of Caller and Callee Information in PDU session charging TS 32.255CR0429
- Add charging requirements for 5MBS TS 32.255CR0430
- Add charging principle for 5MBS TS 32.255CR0431
+ 67 more changes
In Release 19, the FBC function was extended to support new charging principles and information for satellite operations, including store-and-forward modes for SMS and UP CIoT services. The release also introduced volume-based charging for standalone IMS data channels and added specific charging support for new scenarios like disaster roaming, UAS (Unmanned Aircraft Systems), MVNOs providing satellite service, and AIoT services. Furthermore, enhancements were made to Charging Data Records (CDRs) to include information for services such as Ranging and Sidelink Positioning.
- Add charging principle for store and forward satellite operation TS 32.251CR0520
- Add charging information for store and forward satellite operation of SMS service TS 32.251CR0521
- Add charging trigger for store and forward satellite operation with UP CIoT TS 32.251CR0522
- Add charging information for store and forward satellite operation with UP CIoT TS 32.251CR0523
- Rel-19 CR 32.255 Adding use of charging characteristics for CHF Group TS 32.255CR0566
- Rel-19 CR 32.255 Support volume-based charging for standalone IMS data channel TS 32.255CR0573
+ 27 more changes
In Release 20, the FBC function was enhanced to support charging for multi-modality services and to address the charging impacts from enhanced QoS handling in the XRM (Extended Reality and Media) context. It also included corrections and clarifications on QoS Flow Based Charging descriptions and on PDU Session ID handling for charging during EPS-5GS interworking scenarios.
- Add informatin elements to support charging aspects of multi-modality service TS 32.255CR0606
- Rel-20 TS 32.255 Add information elements to address charging impacts from enhanced QoS handling in XRM TS 32.255CR0616
- Rel-20 CR 32.255 Correct some descriptions on QoS flow Based Charging TS 32.255CR0619
- Rel-20 CR 32.255 Correction on PDU Session ID Handling for V-SMF Charging in EPS–5GS Interworking TS 32.255CR0622
Explore further
Broader topics and technologies where FBC plays a role.
Defining Specifications
3GPP specifications that define or reference FBC, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 23.125 v1700 | Flow Based Charging Architecture | Rel-7 |
| TS 23.203 vj20 | Policy and charging control architecture | Rel-19 |
| TS 23.803 v1700 | PCC Architecture Harmonization Study | Rel-7 |
| TR 23.979 vj00 | PoC over 3GPP Systems Architectural Requirements | Rel-19 |
| TS 32.251 vj00 | PS Domain Charging Management | Rel-19 |
| TS 32.255 vk10 | Telecom Management; Charging for 5G Data Connectivity | Rel-20 |
| TS 32.279 vj00 | 5G MBS Session Converged Charging | Rel-19 |
| TS 32.296 vj00 | Online Charging System (OCS) Architecture | Rel-19 |
| TS 32.298 vj30 | Charging Data Record (CDR) Parameter Specification | Rel-19 |