S-NSSAI (Single Network Slice Selection Assistance Information)

An S-NSSAI is the identifier of a single 5G network slice, composed of a Slice/Service Type (SST) and an optional Slice Differentiator (SD). UEs signal Requested S-NSSAIs during registration; the network returns Allowed S-NSSAIs based on subscription and roaming agreements. S-NSSAI values are the primary key that ties a subscriber to a slice instance.