Section: 28.4.4 Network Slice Instance Identifier (NSI ID)
Content: A Network Slice Instance Identifier (NSI ID) uniquely identifies a Network Slice Instance (NSI) within a PLMN or SNPN, when multiple NSIs of a same Network Slice are deployed and there is a need to differentiate between them in the 5GC. See 3GPP TS 23.501[ System architecture for the 5G System (5GS) ]  [119] for the definition of the Network Slice Instance. An NSI may be associated with one or more S-NSSAIs, and an S-NSSAI may be associated with one or more NSIs. The NSI ID is defined as an operator specific string (see clause 6.1.6.2.2 of 3GPP TS 29.510[ 5G System; Network function repository services; Stage 3 ]  [130]).