Section: 6.45.2 Requirements
Content: The 5G system shall allow roaming services to be provided by a roaming services provider in charge of managing roaming agreements, by mediating between two or more PLMNs, while maintaining the privacy and 5G security of any information transmitted between the home and the serving PLMN. NOTE 1: A PLMN can support both bi-lateral direct relationships with other PLMNs and make use of roaming service provider services toward different roaming partners. The 5G system shall allow a roaming services provider to be a trusted entity for either a home PLMN, a visited PLMN or both. NOTE 2: The expected maximum number of roaming service providers is two, one for the home PLMN and another for the visited PLMN. The 5G system shall allow a roaming services provider to accept or reject registration attempts, on behalf of the involved PLMNs, based on the roaming agreements. NOTE 3: Rejecting user registrations using an appropriate release cause permits the UE to be able to reselect another roaming partner or technology. The 5G system shall allow a roaming services provider to identify the origin and destination PLMN, and to verify the authenticity, of every transmitted message. The 5G system shall allow the Roaming services provider to be able to originate and modify messages as per contractually agreed SLAs. The 5G system shall allow the involved PLMNs to be able to identify the origin of any message generated by the roaming services providers as well as to identify any modification made to the exchanged messages by the roaming services providers.