Presented herein are techniques to facilitate visited network selection by a user equipment (UE) based on slice considerations. In one example, a method may include requesting, by a UE that is roaming among a plurality of visited mobile networks, registration for a network connection associated with a slice type; obtaining, by the UE from home mobile network for the UE, a priority for each of the plurality of visited mobile networks and an indication of one or more slice types provided by each of the plurality of visited mobile networks; selecting, by the UE, a highest priority visited mobile network of the plurality of visited mobile networks that provides the slice type; and establishing, by the UE, the network connection with the highest priority visited mobile network of the plurality of visited mobile networks that provides the slice type.

Presented herein are techniques to facilitate visited network selection by a user equipment (UE) based on slice considerations. In one example, a method may include requesting, by a UE that is roaming among a plurality of visited mobile networks, registration for a network connection associated with a slice type; obtaining, by the UE from home mobile network for the UE, a priority for each of the plurality of visited mobile networks and an indication of one or more slice types provided by each of the plurality of visited mobile networks; selecting, by the UE, a highest priority visited mobile network of the plurality of visited mobile networks that provides the slice type; and establishing, by the UE, the network connection with the highest priority visited mobile network of the plurality of visited mobile networks that provides the slice type.

Systems, methods and computer software are disclosed for resolving multiple contexts for a User Equipment (UE) in a wireless network. In one embodiment a method includes maintaining, for a coordinating node hosting a first Radio Access Technology (RAT) controller and a second RAT controller simultaneously, a centrally maintained database; determining, based on the contents of the centrally maintained database, when the UE is registering with the second RAT controller while currently registered with the first RAT controller; and sending, by the second RAT controller, a deregistration command to the first RAT controller the UE was registered with, wherein context is freed and wherein resources held at both the coordinating node and at a base station are freed.

Systems, methods and computer software are disclosed for resolving multiple contexts for a User Equipment (UE) in a wireless network. In one embodiment a method includes maintaining, for a coordinating node hosting a first Radio Access Technology (RAT) controller and a second RAT controller simultaneously, a centrally maintained database; determining, based on the contents of the centrally maintained database, when the UE is registering with the second RAT controller while currently registered with the first RAT controller; and sending, by the second RAT controller, a deregistration command to the first RAT controller the UE was registered with, wherein context is freed and wherein resources held at both the coordinating node and at a base station are freed.

A state notification method, a device, and a system are provided. The state notification method includes: before the first UE leaves a first network on which the first UE camps, determining, according to leaving notification configuration information, whether to send a leaving notification message; and when determining to send a leaving notification message, sending a leaving notification message to a first network device. The leaving notification message is used to indicate that the first UE will leave the first network, and the first network is a network in which the first network device is located.

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method for coordinating an unavailability period parameter of User Equipment (UE) in wireless network is provided. The method includes determining, by an Application Function (AF) of a network apparatus in the wireless network, the unavailability period parameter for the UE based on at least one event to be performed at the UE. Further, the method includes sending, by the AF of the network apparatus, the unavailability period parameter for the UE to an Access and Mobility Management Function (AMF) of the network apparatus. Further, the method includes configuring the unavailability period parameter at the UE. In an embodiment, UE detects it has to execute the event, UE initiates a non-access stratum (NAS) procedure to indicate it will become unavailable by indicating the unavailability period parameter to the 5th generation core (5GC), 5GC forwards the unavailability period parameter to the AF, with this the co-ordination between UE, 5GC and AF is achieved.

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method for coordinating an unavailability period parameter of User Equipment (UE) in wireless network is provided. The method includes determining, by an Application Function (AF) of a network apparatus in the wireless network, the unavailability period parameter for the UE based on at least one event to be performed at the UE. Further, the method includes sending, by the AF of the network apparatus, the unavailability period parameter for the UE to an Access and Mobility Management Function (AMF) of the network apparatus. Further, the method includes configuring the unavailability period parameter at the UE. In an embodiment, UE detects it has to execute the event, UE initiates a non-access stratum (NAS) procedure to indicate it will become unavailable by indicating the unavailability period parameter to the 5th generation core (5GC), 5GC forwards the unavailability period parameter to the AF, with this the co-ordination between UE, 5GC and AF is achieved.

A network function and a method for associating a UE of a UE group to a PDU session with in a CN. The NF establishes a shared PDU session for the UE group before all of the UEs in the UE group register with the CN and binds a UE that has not yet registered with the CN to the shared PDU session when the UE registers with the CN, provided the UE will share at least one of a UL UP connection and a DL UP connection associated with the shared PDU session. The NF may be an SMF.

A method and an apparatus for performing verification using a shared key are disclosed. The method includes: receiving, by a first network element, a registration request message from a second network element, where the registration request message includes a user identifier, first network identifier information, and second network identifier information, the second network identifier information is obtained by processing the first network identifier information by using a shared key, and the shared key is a key used between the first network element and the second network element; verifying, by the first network element, the registration request message by using the shared key; and sending, by the first network element, a registration response message to the second network element. When receiving a registration request from a visited network, a home network verifies the registration request message by using a shared key, to avoid a spoofing attack from the visited network.

One disclosure of the present specification provides a method performed by a terminal that performs registration in a non-3rd generation partnership project (3GPP) access. According to the method, the terminal may receive a rejection message including a value of a back-off timer. In addition, the terminal may determine a value of a non-3GPP de-registration timer on the basis of the value of the back-off timer. In this case, the value of the non-3GPP de-registration timer may be determined to be greater than the value of the back-off timer.