Subscription Owner Standalone Non-Public Network

Description

A Subscription Owner Standalone Non-Public Network (SO-SNPN) is a specific operational model for a 5G Non-Public Network (NPN) as defined in 3GPP Release 17 and beyond. In this model, the network is a Standalone NPN (SNPN), meaning it operates independently without relying on the network functions of a Public Land Mobile Network (PLMN). The key differentiator of an SO-SNPN is that the entity which operates the SNPN also acts as the 'Subscription Owner'—the authority that issues and manages subscriber identities and credentials. This is in contrast to an SNPN that relies on credentials from a PLMN (conceptually similar to roaming).

Architecturally, an SO-SNPN comprises all the standard 5G core network functions (AMF, SMF, UDM, AUSF, etc.) and radio access, but they are dedicated to the private network. The critical component is the Unified Data Management (UDM) function and the Authentication Server Function (AUSF), which are configured with subscriber data owned and provisioned by the SNPN operator itself. When a User Equipment (UE) attempts to access the SO-SNPN, it uses a subscriber identifier specific to that private network. The primary identifier is a Network Identifier (NID) combined with a PLMN ID that is specifically allocated for SNPN use (not a commercial PLMN ID). The UE authenticates directly with the SO-SNPN's AUSF/UDM using credentials stored in its Universal Integrated Circuit Card (UICC) or soft credential store that were provisioned by the SNPN operator.

How it works involves a dedicated registration and authentication procedure. The UE identifies available SNPNs by their broadcasted NID and SNPN PLMN ID. For an SO-SNPN, the UE must possess a subscription specifically for that network. During initial registration, the UE provides its SUCI (Subscription Concealed Identifier) derived from its SNPN-specific subscription. The SO-SNPN's network functions process this request internally. The AUSF performs authentication with the UDM using the credentials owned by the SNPN operator, establishing security context without any interaction with an external public network's home subscriber system. This model gives the private network operator complete autonomy over subscriber lifecycle management, security policies, and service provisioning within its isolated domain.

Purpose & Motivation

The SO-SNPN concept was created to meet the demand from vertical industries (e.g., factories, ports, utilities, campuses) for truly private and autonomous 5G networks. Prior to Release 17, private network concepts often involved some dependency on public mobile network operators, such as using network slicing on a public PLMN or requiring PLMN-issued credentials for access. This dependency could be undesirable for industries requiring full control over their network infrastructure, data sovereignty, operational independence, and specialized security models.

SO-SNPN solves the problem of complete operational separation. It enables an enterprise or vertical to deploy a 5G network as a fully self-contained system, where it is the sole authority for issuing identities to its employees, devices, and sensors. This is crucial for security-sensitive environments where subscriber data must not leave the premises, for specialized devices that will never need public network access, and for operational models where the enterprise wishes to be entirely independent of telecommunications service providers. It addresses limitations of earlier approaches by providing a standardized, 3GPP-defined method to build a private cellular network with the same level of control as a traditional Wi-Fi or wired enterprise network, but with the superior performance, reliability, and mobility features of 5G NR. This empowers verticals to tailor the network precisely to their unique application and security requirements.