Local Home Network ID

Description

The Local Home Network ID (LHN ID) is a fundamental identifier introduced in 3GPP Release 12 to support the concept of Local Home Networks (LHN) within a Public Land Mobile Network (PLMN). A Local Home Network is a network deployment, typically small-scale, that provides local connectivity and services to a restricted set of users, often within a residential or enterprise environment. The LHN ID uniquely identifies such a network within the broader PLMN, allowing the core network and the UE to distinguish between different local home networks and to route traffic appropriately.

Architecturally, the LHN ID is used in conjunction with the Local Home Network Gateway (LHN-GW) and the Local Home Network Management (LHN-M) functions. When a UE connects to a Local Home Network, it may receive the LHN ID during the attach or PDN connection establishment procedure. This identifier is then used by the network to determine whether the UE is authorized to access the local services and to apply the correct policies for local IP access (LIPA) and selected IP traffic offload (SIPTO). The LHN ID is also used for mobility management, ensuring that the UE can maintain its local services when moving between different local home networks or between a local home network and the macro network.

The LHN ID is typically composed of a PLMN ID and a Local Home Network identifier, which may be a numeric or alphanumeric string. The exact format and allocation of the LHN ID are defined in 3GPP specifications such as TS 23.060 and TS 23.401. In TS 23.060, which covers General Packet Radio Service (GPRS) enhancements, the LHN ID is used for GPRS-based local home network access. In TS 23.401, which covers Evolved Packet System (EPS) enhancements, the LHN ID is used for EPS-based local home network access. The LHN ID is signaled between the UE and the network using protocols such as NAS (Non-Access Stratum) and RRC (Radio Resource Control).

One of the key roles of the LHN ID is to enable the UE to discover and select a suitable Local Home Network. When a UE is in the vicinity of a Local Home Network, it may receive broadcast information containing the LHN ID. The UE can then use this information to decide whether to attempt to access the local services offered by that network. The LHN ID also plays a crucial role in access control, as the network can use it to verify that the UE is a member of the Local Home Network and is allowed to use its resources.

In terms of evolution, the LHN ID was introduced in Release 12 and has been maintained in subsequent releases without significant changes to its definition. The concept of Local Home Networks itself has evolved, with enhancements in areas such as mobility, security, and QoS. However, the LHN ID remains a stable identifier that ensures backward compatibility and consistent identification of local home networks across different releases. Its importance is expected to grow with the proliferation of small cells, femtocells, and other local access technologies in 5G and beyond.

Purpose & Motivation

The Local Home Network ID was created to address the need for a standardized way to identify and manage local home networks within a PLMN. Prior to Release 12, there was no unified identifier for such networks, leading to interoperability issues and limited support for local services. The LHN ID enables UEs to access local services seamlessly, supports local IP access and traffic offload, and facilitates mobility management. It solves the problem of distinguishing between multiple local home networks and ensures that UEs can be authorized and authenticated correctly. The LHN ID also supports the growing demand for local connectivity in residential, enterprise, and public spaces, paving the way for new business models and services.