Standalone Non-Public Network

Description

A Standalone Non-Public Network (SNPN) is a complete, independent 5G system defined by 3GPP starting from Release 16. It is a non-public network (NPN) that operates using 5G New Radio (NR) and the 5G Core (5GC) network functions, but it is not reliant on a Public Land Mobile Network (PLMN) for its core network services. An SNPN is identified by a unique combination of a PLMN ID (which is specifically designated for NPN use) and a Network Identifier (NID). This SNPN Identifier (comprising PLMN ID and NID) allows UEs to discover and select the correct private network. The architecture includes all essential 5G network functions: the Next Generation Node B (gNB) for radio access, the Access and Mobility Management Function (AMF), Session Management Function (SMF), User Plane Function (UPF), Authentication Server Function (AUSF), Unified Data Management (UDM), and others, all deployed within the private domain.

How an SNPN works involves dedicated procedures for network discovery, selection, and access control. A UE configured for SNPN access scans for cells broadcasting the SNPN Identifier. Upon discovery, the UE initiates registration with the SNPN. A critical aspect of SNPN operation is authentication and credential management. SNPNs support two primary models: using credentials managed by the SNPN operator itself, or using credentials provided by a separate Credential Holder. The 5G Authentication and Key Agreement (5G-AKA) or EAP-based methods are used, often involving a private authentication server. The network can enforce strict access control, allowing only pre-authorized UEs (e.g., company devices, sensors) to connect.

The role of an SNPN is to provide a secure, isolated, and performant communication platform for vertical industries. It enables features like network slicing, ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC) tailored to the specific needs of a factory, port, hospital, or energy grid. The operator of the SNPN has full control over the network's configuration, policy, and data, ensuring that sensitive traffic remains on-premises and is not routed through public networks. This makes SNPNs a cornerstone for Industry 4.0, enabling advanced use cases like automated guided vehicles, real-time process control, and augmented reality-assisted maintenance.

Purpose & Motivation

SNPNs were created to meet the stringent requirements of industrial and enterprise digital transformation, which public networks could not fully satisfy. Public networks are designed for broad consumer coverage and general-purpose services, often lacking the guaranteed performance, ultra-low latency, data sovereignty, and deep customization needed for critical industrial operations. Previous approaches like local Wi-Fi or LTE-based private networks were either not standardized for seamless mobility and service integration (Wi-Fi) or lacked the full feature set and architectural clarity of 5G (pre-Rel-16 private LTE).

The primary problems SNPNs solve are: 1) **Isolation and Security**: Providing a physically or logically isolated network where sensitive data never leaves the premises, crucial for intellectual property protection and operational technology (OT) security. 2) **Predictable Performance**: Offering dedicated resources with guaranteed Service Level Agreements (SLAs) for latency, reliability, and bandwidth, which is essential for time-sensitive industrial automation. 3) **Operational Autonomy**: Allowing the enterprise to own and operate the network independently, without dependency on a public mobile network operator's priorities or timelines. The motivation for standardizing SNPNs in 3GPP was to create a globally harmonized, interoperable framework for private 5G, avoiding proprietary solutions and fostering a healthy ecosystem of network equipment and devices.