Product Specific Applications

Description

Product Specific Applications (PSA) is a term used across numerous 3GPP specifications to denote application functions or services that are not generic but are tied to a specific commercial product, service bundle, or use case. It is not a single protocol or network function but a conceptual entity used in requirement and architectural modeling. PSAs represent the logical endpoint or source of service-specific traffic and signaling that the 5G System (5GS) must support. They are often discussed in the context of service-based architecture, network exposure, and quality of service (QoS) differentiation.

Architecturally, a PSA interacts with the 5G Core Network (5GC) through defined interfaces, primarily the Network Exposure Function (NEF) or directly with the User Plane Function (UPF) for traffic steering. The PSA can be an Application Function (AF) as defined in the 5GC architecture, but with the distinguishing characteristic of being product-specific. This means its communication with the network carries requirements unique to the product it enables, such as specific QoS parameters (e.g., latency, reliability), charging policies, or mobility restrictions. The 5GC uses the information provided by or about the PSA to apply appropriate network policies.

How it works involves the PSA (or an entity representing it, like an AF) providing session or service-related information to the 5GC. For example, a PSA for a real-time gaming service might request a guaranteed bit rate and low-latency QoS flow for its users via the NEF. The Policy Control Function (PCF) would then generate policies based on this request and the user's subscription, and the Session Management Function (SMF) would enforce them by configuring the UPF accordingly. The role of the PSA concept is to provide a formal model for these product-specific interactions, ensuring the network can be dynamically tailored to support a vast array of specialized services beyond basic connectivity, which is central to the 5G vision of network-as-a-service.

Purpose & Motivation

The concept of Product Specific Applications exists to address the need for the 3GPP system to support a diverse and ever-growing ecosystem of specialized services, each with unique network requirements. In early mobile networks, services were largely monolithic (e.g., voice, SMS, basic internet). As networks evolved, operators and third parties began offering differentiated products like streaming bundles, IoT solutions, and enterprise VPNs, which required the network to treat their traffic differently.

PSA provides a standardized way to model these bespoke services within the 3GPP architecture. It solves the problem of how to formally describe and integrate the requirements of a specific commercial product into the network's control and management planes. Before such modeling, enabling a new service often required proprietary integrations or broad, inefficient network configurations. The PSA concept, particularly as refined in the 5G service-based architecture, allows for dynamic, policy-driven network slicing and QoS management on a per-application or per-product basis. This enables operators to efficiently monetize their networks by offering tailored connectivity as a product feature.