Person to Application and Application to Person

Description

P2A2P (Person to Application and Application to Person) is a service communication paradigm introduced in 3GPP Release 19 that describes traffic and interaction patterns in which a human user communicates with a server-hosted application, and that application communicates back to the user. Unlike traditional client-server models where the user simply consumes content, P2A2P explicitly captures both directions as first-class communication scenarios: the person initiates requests, commands, or media toward an application (Person to Application), and the application proactively generates responses, notifications, media, or actions directed at the person (Application to Person). This bidirectional framing matters because 3GPP systems must support both latency-sensitive uplink interactions (for example, gesture or voice input) and downlink delivery of rich generated content, often within the same session.

Architecturally, P2A2P is realized over existing 3GPP service enablers rather than a single new network function. The user equipment (UE) connects through the 5G System (5GS), and application traffic is carried over user-plane paths negotiated via PDU sessions, typically anchored at an Application Function (AF) or edge application server. The application may reside in the public cloud, at a multi-access edge computing (MEC) host, or on a local enterprise server. Session and service continuity, QoS flows, and policy control (PCF) ensure that the Person-to-Application direction and the Application-to-Person direction receive appropriate treatment, which is important when one direction is bursty uplink (such as real-time input) and the other is bandwidth-heavy downlink (such as streaming generated media).

P2A2P is closely related to immersive and AI-driven service categories studied in 3GPP, including extended reality (XR), conversational AI, and network-hosted agents. In these use cases the boundary between 'user sends input' and 'application sends output' blurs, since an application may respond continuously and adaptively to user behaviour. P2A2P therefore requires the network to support low round-trip latency, high uplink reliability, and consistent QoS across both directions. The 3GPP studies captured in TR 24.186 examine protocol aspects and traffic characteristics, while TR 33.929 addresses security considerations such as authentication of the application, protection of user data, and authorization of application-initiated actions toward the user.

From a service delivery perspective, P2A2P influences how operators design QoS profiles, charging models, and exposure of network capabilities to application providers. Because the application actively pushes to the person, notification mechanisms such as NEF-based event exposure, service-level agreements for latency, and edge deployment become relevant. Charging may need to distinguish application-initiated downlink from user-initiated uplink, or to bundle the two directions into a single service session. This is a departure from purely user-initiated data sessions and requires richer policy and charging rules.

In summary, P2A2P provides 3GPP with a vocabulary and a set of requirements for interactive human-to-application sessions in which both directions carry meaningful, often real-time traffic. It supports the shift from content consumption toward AI-assisted and immersive interaction, and it drives requirements on QoS, edge computing, security, and charging that are studied across Releases 19 and 20.

Purpose & Motivation

P2A2P exists because 3GPP service models historically treated uplink and downlink somewhat asymmetrically, with most services framed as the user requesting content from an application. As conversational AI, immersive XR, and network-hosted agents emerged, it became clear that the Application-to-Person direction deserves equal attention: applications now generate rich, latency-sensitive, and personalized output continuously in response to user behaviour. Without a dedicated term and study, requirements for QoS symmetry, uplink reliability, and application-initiated actions could be overlooked.

The concept also addresses the limitations of treating interactive services as generic data traffic. Generic QoS flows cannot easily express the intertwined nature of real-time user input and application-generated output, nor the security needs of an application acting on behalf of or toward a user. P2A2P gives 3GPP a framework to specify protocol behaviour, security controls, and policy handling for these bidirectional interactions.

Finally, P2A2P supports the commercial and architectural shift toward edge-hosted and AI-driven applications. It provides a basis for operators to offer differentiated connectivity, exposure of network capabilities, and charging models that reflect the value of both directions of an interactive session.