Description
The Home Policy and Charging Enforcement Function (H-PCEF) is a specialized instance of the PCEF that operates within the boundaries of the subscriber's Home Public Land Mobile Network (HPLMN). Introduced in 3GPP Release 7 as part of the Policy and Charging Control (PCC) framework, the H-PCEF's role becomes particularly significant in roaming scenarios, specifically in the Home Routed roaming architecture. In this architecture, the user's data traffic is routed back to the HPLMN, and the H-PCEF is the entity that applies the policy and charging rules. It is typically collocated with or is the Gateway GPRS Support Node (GGSN) in 3G or the Packet Data Network Gateway (PGW) in 4G/5G within the home network. The H-PCEF interfaces with the Home Policy and Charging Rules Function (H-PCRF) via the Gx reference point. The H-PCRF provides it with PCC rules that contain instructions for bearer control (e.g., QoS parameters like guaranteed bit rate), gating control (allowing/blocking packets), and charging control (identifying charging keys and metering methods). The H-PCEF enforces these rules in real-time on the user plane traffic. It performs deep packet inspection (DPI) to detect service data flows, applies the corresponding QoS (e.g., setting DiffServ Code Points), and interacts with the Online Charging System (OCS) via the Gy interface for credit management or the Offline Charging System (OFCS) via the Gz interface for CDR generation. When a user is roaming, the Visited PCEF (V-PCEF) in the visited network may handle local breakout traffic, but for home-routed traffic, the H-PCEF is the ultimate policy enforcement point, ensuring the home operator's service and charging policies are applied consistently.
Purpose & Motivation
The H-PCEF was developed to enable home network operators to maintain direct control over the quality of service, charging, and policy enforcement for their subscribers, even when those subscribers are using roaming partners' radio access networks. Prior to PCC and the clear definition of H-PCEF, policy enforcement in roaming scenarios was less granular and often left to the visited network, which could lead to inconsistent service experiences and complex settlement processes. The H-PCEF, as part of the Home Routed roaming model, solves this by ensuring that the subscriber's service profile, defined and controlled in the HPLMN, is faithfully executed. This allows the home operator to offer tiered service plans, implement fair usage policies, and apply accurate charging based on their own business rules, regardless of the visited network. Its creation was motivated by the need for more sophisticated service differentiation, the growth of mobile data usage, and the requirement for a standardized architecture that supports complex inter-operator settlements for data services. It forms the enforcement backbone for monetizing data services and ensuring network resources are used according to subscriber agreements.
Key Features
- Enforcement point for PCC rules (QoS, gating, charging) in the HPLMN
- Critical role in Home Routed roaming architecture for data sessions
- Deep Packet Inspection (DPI) for service flow detection and classification
- Interaction with OCS (Online Charging System) for real-time credit control
- Interaction with OFCS (Offline Charging System) for charging data record generation
- Bearer binding and enforcement of QoS parameters on the user plane
Evolution Across Releases
Initial introduction of the PCEF concept within the PCC architecture. The H-PCEF was defined as the PCEF residing in the HPLMN, with its primary role in enforcing policies for home-routed roaming traffic. Key interfaces Gx (to PCRF), Gy (to OCS), and Gz (to OFCS) were specified, establishing the foundation for dynamic policy and charging control.
Defining Specifications
| Specification | Title |
|---|---|
| TS 23.203 | 3GPP TS 23.203 |