Abstract: A method for automatically triggering network slice selection assistance information (NSSAI) availability information updates with a network slice selection function (NSSF) includes receiving, from an access and mobility management function (AMF), a service request message. The method further includes determining, that the NSSAI availability information for the AMF is not present in an NSSAI availability information database maintained by the NSSF. The method further includes sending, to the AMF, a message for triggering the AMF to update its NSSAI availability information with the NSSF, receiving, an NSSAI Availability PUT request including NSSAI availability information for the AMF, and updating, the NSSAI availability information database to include the NSSAI availability information for the AMF.

Abstract: A method for managing NSSAI availability information at an NSSF includes receiving and storing NSSAI availability information from NF service consumers. The method further includes maintaining time values usable to determine expiration times for NSSAI availability information database records, where the time values are updated when a corresponding record is updated. The method further includes auditing the records, and, in response to failing to receive a request to update the NSSAI availability information for one of the NSSAI information database records within an expiration time, marking the record as stale. When a trigger is detected for providing NSSAI availability information from one of the database records that is marked as stale, the NSSF refrains from providing the NSSAI availability information to the NF service consumer.

Abstract: A method for providing for reliable service based interface (SBI) message transport using zero event notifications includes, at a consumer NF, sending an SBI message to a producer NF indicating an intent to use zero event notification messaging. The method further includes, at the producer NF, receiving the SBI message indicating the intent to use zero event notification messaging, and, transmitting a zero event notification request message to the consumer NF using a callback URI from the SBI message to confirm the callback URI and connectivity from the producer NF to the consumer NF. The method further includes, at the consumer NF, receiving the zero event notification request message and, in response, sending a zero event notification response message to the producer NF. The method further includes, at the producer NF, receiving the zero event notification response message, and, in response, continuing SBI subscription messaging with the consumer NF.

Abstract: A method for providing for reliable service based interface (SBI) message transport using zero event notifications includes, at a consumer NF, sending an SBI message to a producer NF indicating an intent to use zero event notification messaging. The method further includes, at the producer NF, receiving the SBI message indicating the intent to use zero event notification messaging, and, transmitting a zero event notification request message to the consumer NF using a callback URI from the SBI message to confirm the callback URI and connectivity from the producer NF to the consumer NF. The method further includes, at the consumer NF, receiving the zero event notification request message and, in response, sending a zero event notification response message to the producer NF. The method further includes, at the producer NF, receiving the zero event notification response message, and, in response, continuing SBI subscription messaging with the consumer NF.

Abstract: A method for providing for policy-based access and mobility management function (AMF) selection using network slice selection assistance information (NSSAI) availability information obtained from an NSSAI availability service includes, at a network slice selection function (NSSF) including at least one processor, obtaining, from an NSSAI availability service, NSSAI availability information regarding a plurality of AMFs. The method further includes receiving, from a first AMF, a network slice selection request specifying a network slice service requested by a user equipment (UE). The method further includes generating, based on the NSSAI availability information and the network slice service requested by the UE, a prioritized list including an identity of at least one AMF for supporting the network slice service. The method further includes communicating the prioritized list to the first AMF.

Abstract: A method for providing for policy-based access and mobility management function (AMF) selection using network slice selection assistance information (NSSAI) availability information obtained from an NSSAI availability service includes, at a network slice selection function (NSSF) including at least one processor, obtaining, from an NSSAI availability service, NSSAI availability information regarding a plurality of AMFs. The method further includes receiving, from a first AMF, a network slice selection request specifying a network slice service requested by a user equipment (UE). The method further includes generating, based on the NSSAI availability information and the network slice service requested by the UE, a prioritized list including an identity of at least one AMF for supporting the network slice service. The method further includes communicating the prioritized list to the first AMF.