Support for network service

An access and mobility management function (AMF) comprising one or more processors and memory storing instructions that, when executed by the one or more processors, cause the AMF to:

• receive, from a wireless device, a non-access stratum (NAS) message comprising:
• an establishment request for a protocol data unit (PDU) session;
• and
• a network slice identifier of an allowed network slice within which the PDU session is established, wherein the allowed network slice comprises a first network slice;
• send, to the wireless device, one or more messages comprising a first list of allowed network slices comprising the first network slice, wherein based on the AMF determining that the first network slice becomes unavailable, the one or more messages further comprise:
• a second list of alternative network slices comprising a second network slice and a third network slice;
• and
• information indicating which one of the second network slice and the third network slice is an alternative network slice for the first network slice;
• wherein the information indicates that the second network slice is an alternative network slice for the first network slice;
• the first list of allowed network slices further comprises a fourth network slice;
• and
• the information indicates that the third network slice is an alternative network slice for the fourth network slice;
• and
• receive, from the wireless device, a second request message, for a second PDU session, indicating the alternative network slice.

A method comprising:

• sending, by a wireless device to an access and mobility function (AMF), a non-access stratum (NAS) message comprising:
• an establishment request for a protocol data unit (PDU) session;
• and
• a network slice identifier of an allowed network slice within which the PDU session is established, wherein the allowed network slice comprises a first network slice;
• receiving, by the wireless device from the AMF, one or more messages comprising a first list of allowed network slices comprising the first network slice, wherein based on the AMF determining that the first network slice becomes unavailable, the one or more messages further comprise:
• a second list of alternative network slices comprising a second network slice and a third network slice;
• and
• information indicating which one of the second network slice and the third network slice is an alternative network slice for the first network slice;
• wherein the information indicates that the second network slice is an alternative network slice for the first network slice;
• the first list of allowed network slices further comprises a fourth network slice;
• and
• the information indicates that the third network slice is an alternative network slice for the fourth network slice;
• and
• sending, by the wireless device to the AMF, a second request message, for a second PDU session, indicating the alternative network slice.