Network slice configuration update

A network slice configuration update method, the method being performed by a first network function in a Public Land Mobile Network, PLMN, to which a user equipment, UE is trying to register, wherein the UE belongs to a Home PLMN, HPLMN, and the PLMN is not the HPLMN, the method comprising:

• the first network function receiving a certain parameter transmitted by the UE, wherein the parameter indicates to the first network function that the first network function shall provide to the UE all of the network slice identifiers that can be used in the PLMN;
• the first network function, after receiving the certain parameter, obtaining subscription information for the UE;
• and
• after obtaining the subscription information and as a consequence of receiving the certain parameter, the first network function transmitting to the UE a message containing all of the network slice identifiers that can be used in the PLMN.

A network slice configuration update method, the method being performed by a management function, the method comprising:

• the management function obtaining information indicating that a user equipment's Subscribed Network Slices has been updated;
• as a result of obtaining the information indicating that the user equipment's Subscribed Network Slices has been updated, the management function sending to the user equipment, UE, a message containing information indicating that the UE's Subscribed Network Slices have been updated wherein
• obtaining the information comprises the management function receiving from a data manager a message containing a parameter explicitly indicating that the UE's Subscribed Network Slices has been updated and/or containing the UE's updated Subscribed Network Slices, and
• the message from data manager is a Nudm_SDM_Notification.

A network slice configuration update method, the method being performed by a data manager, the method comprising:

• the data manager detecting that Subscribed Network Slices for a user equipment, UE, has been updated;
• after detecting that the UE's Subscribed Network Slices has been updated, the data manager setting to a certain value a flag for the UE, which flag is applicable for a plurality of PLMNs and indicates that the UE's Subscribed Network Slices has been updated;
• after setting the flag for the UE, the data manager receiving a first message transmitted by a first management function, wherein the first message includes a UE identifier for identifying the UE;
• in response to receiving the first message, the data manager checking whether the flag for the UE is set to the certain value;
• if the flag for the UE is set to the certain value, then the data manager sends to the first management function a second message containing information indicating that the UE's Subscribed Network Slices has been updated;
• and
• after sending the second message to the first management function, the data manager clears the flag.

A user equipment, UE, the UE being adapted to:

• obtain information indicating that a set of one or more network slice identifiers included in the UE's subscription information, Subscribed Network Slices, has been updated;
• after obtaining the information indicating that the Subscribed Network Slices has been updated, set a particular flag for a first Visited Public Land Mobile Network, VPLMN, to a certain value;
• during a registration process for registering with the first VPLMN, determine whether the particular flag is set to the certain value;
• and
• as a result of determining that the particular flag is set to the certain value, send to a network function within the VPLMN a notification indicating that the network function should provide to the UE a set of network slice identifiers for the VPLMN.