Section: 28.3.2.2.9 Prefixed Tracking Area Identity based N3IWF FQDN
Content: The Prefixed Tracking Area Identity based N3IWF FQDN, used by a UE that is configured with Slice-specific N3IWF prefix configuration, shall be constructed as specified for the Tracking Area Identity based N3IWF FQDN in clause 28.3.2.2.3, with the addition of <Prefix> before the TAC. The <Prefix> is provided in the Slice-specific N3IWF prefix configuration for the selected PLMN that contains S-NSSAIs that match all (or most, in case there is no full match) of the S-NSSAIs that the UE is going to include in the Requested NSSAI in the subsequent Registration procedure, and is specified in 3GPP TS 24.526[ User Equipment (UE) policies for 5G System (5GS); Stage 3 ]  [144]. There are two Prefixed Tracking Area Identity based N3IWF FQDNs defined: one based on a TAI with a 2 octet TAC and a 5GS one based on a 3 octet TAC. 1) The Prefixed Tracking Area Identity based N3IWF FQDN using a 2 octet TAC shall be constructed respectively as: "<Prefix>.tac-lb<TAC-low-byte>.tac-hb<TAC-high-byte>.tac.n3iwf.5gc.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" The syntax and semantics of <TAC-high-byte>, <TAC-low-byte>, <MNC>, and <MCC> are specified in clause 28.3.2.2.3. As an example, the Prefixed Tracking Area Identity based N3IWF FQDN for the TAC H'0B21, MCC 345, MNC 12, and an example <Prefix> value "ssn3iwfprefix-Y" is coded in the DNS as: "ssn3iwfprefix-Y.tac-lb21.tac-hb0b.tac.n3iwf.5gc.mnc012.mcc345.pub.3gppnetwork.org" 2) The 5GS Prefixed Tracking Area Identity based N3IWF FQDN using a 3 octet TAC shall be constructed respectively as: "<Prefix>.tac-lb<TAC-low-byte>.tac-mb<TAC-middle-byte>.tac-hb<TAC-high-byte>.5gstac.n3iwf.5gc.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" The syntax and semantics of <TAC-high-byte>, <TAC-middle-byte>, <TAC-low-byte>, <MNC>, and <MCC> are specified in clause 28.3.2.2.3. As an example, the 5GS Prefixed Tracking Area Identity based N3IWF FQDN for the 5GS TAC H'0B1A21, MCC 345, MNC 12, and an example <Prefix> value "ssn3iwfprefix-Y" is coded in the DNS as: "ssn3iwfprefix-Y.tac-lb21.tac-mb1a.tac-hb0b.5gstac.n3iwf.5gc.mnc012.mcc345.pub.3gppnetwork.org"