Restricted Local Operator Services

Description

Restricted Local Operator Services (RLOS) is a service control mechanism defined within the 3GPP architecture, primarily managed by the Home Subscriber Server (HSS) and applied through the Policy and Charging Control (PCC) framework. The core function of RLOS is to impose a specific service profile on a user's session, which selectively permits only a predefined set of services deemed essential or locally relevant by the network operator. When a user is flagged for RLOS, the HSS provides an indication to the serving network nodes, such as the MME in EPS or the AMF in 5GS. This indication triggers the enforcement of a corresponding PCC rule set, which is configured to allow only certain traffic flow templates (TFTs). Typically, these permitted TFTs are for accessing the operator's own service network (e.g., for customer care, balance top-up, or service portals) and for emergency services (e.g., calls to 112, 911). All other outgoing communication attempts, such as regular voice calls or data sessions to the public internet, are blocked by the Policy and Charging Enforcement Function (PCEF) or the Session Management Function (SMF) with UPF. The architecture integrates with the Rx and Gx interfaces (or their 5GC equivalents) to dynamically apply these policies. RLOS is not a standalone network function but a service logic implemented across core network elements, leveraging existing subscription data and policy control mechanisms to achieve granular service restriction. Its role is to provide a flexible tool for operators to manage service accessibility in a controlled manner, aligning with commercial, regulatory, or network management needs without requiring complete service disconnection.

Purpose & Motivation

RLOS was introduced to address specific operational and commercial scenarios where a subscriber needs to be restricted from making general outgoing calls but must retain access to a minimal set of operator-managed services. A primary use case is for inbound roamers who have not established a roaming agreement or whose credit has been exhausted; instead of denying all service, the operator can apply RLOS to allow the user to contact customer service for assistance or to top up their account. It also serves users on restrictive service plans, ensuring they can always reach emergency services and operator support. Historically, without such a feature, the options were binary: either full service access or complete service barring. RLOS provides a middle ground, enhancing customer experience by maintaining a lifeline to essential services while protecting the operator from potential revenue loss from unpaid usage. Its creation was motivated by the need for more sophisticated service control within the PCC architecture defined from Release 7 onwards, allowing for dynamic, policy-driven service differentiation beyond simple barring lists.

Key Features

• Dynamic policy enforcement via the PCC (Policy and Charging Control) architecture.
• Selective allowance of traffic to operator-defined service destinations and emergency numbers.
• Integration with HSS/UDM for subscriber-specific service profile indication.
• Application in both 4G EPS (via MME, P-GW) and 5G 5GC (via AMF, SMF, UPF) systems.
• Support for scenarios like roaming, credit control, and limited service subscriptions.
• Utilizes standardized traffic flow templates (TFTs) for precise packet filtering and gating.

Evolution Across Releases

Defining Specifications