Description
The Converged Charging System (CCS) is a core network function defined by 3GPP for online charging. It represents a fundamental architectural evolution from legacy, service-specific charging systems to a unified, real-time charging platform. The CCS integrates the functions of the Online Charging System (OCS) and the Charging Data Function (CDF) for online charging, providing a single point of interaction for network elements requiring real-time credit control. It operates based on the Diameter Ro and Gy reference points, interfacing with Policy and Charging Rules Functions (PCRF/PCRF), application servers, and network gateways.
Architecturally, the CCS is built around the concept of a Charging Function (CHF), which is its central logical entity. The CHF communicates with network functions via standardized service-based interfaces (e.g., Nchf) in 5G Core networks. It processes charging events in real-time, applying tariff logic, deducting funds from user accounts, and granting or denying service units based on available credit. Key internal components include the Account Balance Management Function (ABMF) for managing subscriber balances and the Rating Function (RF) for determining the monetary cost of service usage events.
Its role in the network is pivotal for monetization and service control. The CCS authorizes network resource usage in real-time before or during a service delivery, enabling prepaid, on-demand, and sponsored data services. It generates standardized Charging Data Records (CDRs) for billing and settlement. By decoupling charging logic from specific network services, the CCS allows operators to rapidly introduce and tariff new services—like 5G network slices, IoT data plans, or edge computing services—without deploying separate charging infrastructure for each.
Purpose & Motivation
The CCS was created to address the limitations of fragmented, legacy charging systems where each service type (circuit-switched voice, packet data, SMS, IMS) had its own dedicated charging platform. This siloed approach led to operational complexity, high costs, and an inability to offer unified, cross-service charging plans (e.g., shared data buckets for voice and data). The proliferation of new IP-based services and the shift towards all-IP networks (IMS) demanded a more agile and consolidated charging architecture.
The primary problem it solves is the convergence of real-time charging across all access technologies (2G/3G/4G/5G, fixed) and all service types onto a single, standardized platform. This convergence enables operators to implement innovative, personalized pricing models and launch services faster. It also provides a future-proof foundation for charging in 5G Standalone networks, where network slicing and service-based architecture require a flexible, software-defined charging function that can interact dynamically with other network functions via APIs.
Historically, its introduction in 3GPP Release 11 marked a significant step towards the full realization of the Policy and Charging Control (PCC) architecture, providing a unified online charging entity. It addressed the need for a single source of truth for subscriber credit and balance management, improving revenue assurance and reducing the risk of credit fraud across disparate service domains.
Classification
Release Timeline
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (3 CRs across 3 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the Converged Charging System (CCS) was introduced as a new network entity for IMS-based P2P Content Distribution Services, primarily functioning as a Content Cache Server. Its key capabilities include caching content segments, joining P2P swarms under the direction of a Tracker AS, and retrieving content from a Content Source Server (CSS) when needed. The release also defined specific interfaces for the CCS, such as the Tc interface for communication with the Tracker AS and the SC_s and SC_m interfaces for interaction with the CSS.
- Charging mode clarifications in Converged Charging System TS 32.240CR0402
In Release 17, the Converged Charging System (CCS) was newly introduced as a defined network function within the IMS-based P2P Content Distribution Services framework. The CCS acts as a Content Cache Server, responsible for caching content segments and providing them to UEs under the direction of a Tracker AS, utilizing specific interfaces like Tc, PP_s1, and PP_m1 for control and media transfer. New procedures were also defined, such as the CCS Joining Procedure, where a Tracker AS can instruct a CCS to join a P2P swarm and retrieve content from a Content Source Server.
- Add the CCS in the definitions TS 32.240CR0422
In Release 18, the Converged Charging System (CCS) was enhanced as a new network entity for IMS-based Peer-to-Peer Content Distribution Services, introducing specific interfaces for its operation. These include the Tc interface for communication with the Tracker AS, and the PP_s1 and PP_m1 interfaces for interaction with user equipment. The release also defined procedures such as the CCS Joining Procedure, enabling the CCS to cache and distribute content within a P2P swarm under the Tracker AS's direction.
- Correction to simultaneous BWP switch across CCs TS 38.306CR1232
Explore further
Broader topics and technologies where CCS plays a role.
Defining Specifications
3GPP specifications that define or reference CCS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 23.844 vc00 | IMS P2P Content Distribution Services Study | Rel-12 |
| TS 25.709 vf00 | Simplified HS-SCCH for UMTS Study | Rel-15 |
| TS 25.766 vd10 | Network-Assisted Interference Cancellation for UMTS | Rel-13 |
| TS 28.203 vi10 | Charging management | Rel-18 |
| TR 28.840 vi10 | Technical Report | Rel-18 |
| TR 28.843 vi10 | Technical Report on Charging Aspects for Vertical Scenarios | Rel-18 |
| TS 29.594 vj20 | 5G Spending Limit Control Service Stage 3 | Rel-19 |
| TS 32.240 vj40 | Charging Management Architecture & Principles | Rel-19 |
| TS 32.255 vk10 | Telecom Management; Charging for 5G Data Connectivity | Rel-20 |
| TS 32.256 vj40 | 5G Connection & Mobility Charging Spec | Rel-19 |
| TS 32.279 vj00 | 5G MBS Session Converged Charging | Rel-19 |
| TS 32.290 vj50 | 5G Charging for Service Based Interface | Rel-19 |
| TS 38.306 vj00 | NR UE Radio Access Capability Parameters | Rel-19 |
