For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905. non-public network: private slice:

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905. 5G 5GC A/V CD/DVD IoT KPI LSA MIoT MNO OTT SCEF SPaaS URLLC V/NFs

5G supports new business role models relevant for 3GPP systems. In previous generations, business role models centered on two key types of relationships: those between Mobile Network Operators (MNOs) and their subscribers and those between MNOs (e.g., roaming, RAN sharing). To a limited extent, relationships between MNOs and 3rd party application providers have also been supported in the form of APIs (e.g., by the SCEF interface - see TS 23.682) allowing access to specific network capabilities, such as those used by 3rd party applications to access UE location information. 5G opens the door to new business role models for 3rd parties, allowing 3rd parties more control of system capabilities. This document considers these new business roles and how 3GPP can best support the trust relationships between MNOs and 3rd parties resulting from these new business role models. In 5G three role models are envisaged for stakeholders.

1. The MNO owns and manages both the access and core network.
2. An MNO owns and manages the core network, the access network is shared among multiple operators (i.e., RAN sharing).
3. Only part of the network is owned and/or managed by the MNO, with other parts being owned and/or managed by a 3rd party.

The first two are essentially those found in previous generations of 3GPP systems, where MNOs are operating PLMNs. In 5G it is expected that a 3rd party can take on the role of an MNO, however in this case the 3rd party would operate its own network. From a 3GPP perspective, stakeholder role models 1 and 2 are the same whether an MNO or vertical 3rd party is involved. Basic support for the 3rd party stakeholder role model was provided in previous generations via APIs which allowed minimal access to or management of network capabilities. In contrast, the 5G enhancements will allow greater control and ownership by the 3rd party, which will require increased trust between the MNO and 3rd party. These new trust relationships become even more impactful when network slicing is considered, particularly where the 3rd party is authorized to control some aspects of network slices that are owned by the MNO. With the introduction of network slicing, the third stakeholder role model above warrants additional investigation to understand the trust relationships between MNOs and 3rd parties. There are four potential business relationship models impacting the trust relationships for stakeholder role model 3.

• Model 3a: MNO provides the virtual/physical infrastructure and V/NFs; a 3rd party uses the functionality provided by the MNO,
• Model 3b: MNO provides the virtual/physical infrastructure and V/NFs; a 3rd party manages some V/NFs via APIs exposed by the MNO,
• Model 3c: MNO provides virtual/physical infrastructure; a 3rd party provides some of the V/NFs,
• Model 3d: a 3rd party provides and manages some of the virtual/physical infrastructure and V/NFs.

  Of these models, 3a and 3b have been addressed by the requirements in place in TS 22.261. Provision has been made to ensure appropriate APIs and management functions to support this extended 3rd party access and control of capabilities provided by the MNO, and to do so in a secure manner. Within these two models, the 3rd party has increasing control over the network capabilities that support its service. However, this control is limited to what is allowed by the MNO through the provided APIs. Models 3c and 3d provide extended control for the 3rd party on the network capabilities supporting its service. However, these models still require ensuring appropriate levels of security are maintained for any communications. In four potential business relationship models, three management role models can be considered for models 3c and 3d.

1. MNO manages all virtual/physical infrastructure and all V/NFs including 3rd party's ones,
2. 3rd party manages its own virtual/physical infrastructure and/or its own V/NFs; MNO manages the others.
3. 3rd party manages virtual/physical infrastructure and/or V/NFs including its own virtual/physical infrastructure and/or V/NFs and some MNO's virtual/physical infrastructure and/or V/NFs; MNO manages the others.

From the 3rd party perspective, the management role models 2 and 3 support the 3rd party management function and provide extended management for the MNO to coordinate with the 3rd party management. The 3rd party may use suitable APIs provided by the MNO to directly manage the V/NFs as well as the infrastructure resources so that it can properly handle when their business requirements are changed.

The degree of trust between the MNO and 3rd party has an impact on the 3GPP system. In model 3a, the 3rd party must be able to trust the MNO to provide the necessary capabilities. In the other models, the MNO must also be able to ensure that the degree of control provided to the 3rd party does not allow the 3rd party to negatively impact the MNOs network. TS 22.261 addresses the trust relationships for models 3a and 3b. For models 3c and 3d to be supported, additional consideration is needed on the mechanisms to provide the isolation and interfaces that give the 3rd party the appropriate level of control while securing the PLMN. Specifically for models 3c and 3d, where the 3rd party provides V/NFs or provides and manages some of the virtual/physical infrastructure and V/NFs, SLAs may be used to address some trust issues, such as what each party will provide and manage. However, the principles of trust and verification also come into play. The 3rd party must be able to verify, though the management interface, that all terms of the SLA are being met by the MNO. Similarly, the MNO must be able to verify that the 3rd party is managing resources appropriately so that there is no adverse impact to the rest of the network. Appropriate management interfaces are needed to support both the network operator and 3rd party. The underlying trust relationships support such models and may lead to new 3GPP requirements, such as the abilities to provide slice based authentication and slice based encryption and integrity protection. The present document considers the trust relationships related to extended control by a 3rd party.