Section: 19.4.2.9A.3 Tracking/Location Area Identity based Emergency ePDG FQDN
Content: There are two Tracking Area Identity based Emergency ePDG FQDNs defined: one based on a TAI with a 2 octet TAC and a 5GS one based on a 3 octet TAC. 1) The Tracking Area Identity based Emergency ePDG FQDN using a 2 octet TAC and the Location Area Identity based Emergency ePDG FQDN shall be constructed as specified for the Tracking Area Identity based ePDG FQDN and the Location Area Identity based ePDG FQDN in clause 19.4.2.9.3, with the addition of the label "sos" before the labels "epdg.epc". The Tracking Area Identity based Emergency ePDG FQDN and the Location Area Identity based Emergency ePDG FQDN shall be constructed as follows: "tac-lb<TAC-low-byte>.tac-hb<TAC-high-byte>.tac.sos.epdg.epc.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" and "lac<LAC>.sos.epdg.epc.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org" As examples, - the Tracking Area Identity based Emergency ePDG FQDN for the TAC H'0B21, MCC 345 and MNC 12 is coded in the DNS as: " tac-lb21.tac-hb0b.tac.sos.epdg.epc.mnc012.mcc345.pub.3gppnetwork.org" - the Location Area Identity based Emergency ePDG FQDN for the LAC H'0B21, MCC 345 and MNC 12 is coded in the DNS as: " lac0b21.sos.epdg.epc.mnc012.mcc345.pub.3gppnetwork.org" 2) The 5GS Tracking Area Identity based Emergency ePDG FQDN using a 3 octet TAC shall be constructed as specified for the 5GS Tracking Area Identity based ePDG FQDN in clause 19.4.2.9.3, with the addition of the label "sos" before the labels "epdg.epc". The 5GS Tracking Area Identity based Emergency ePDG FQDN shall be constructed as follows: "tac-lb<TAC-low-byte>.tac-mb<TAC-middle-byte>.tac-hb<TAC-high-byte>.5gstac.sos. epdg.epc.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org " As examples, - the 5GS Tracking Area Identity based Emergency ePDG FQDN for the 5GS TAC H'0B1A21, MCC 345 and MNC 12 is coded in the DNS as: "tac-lb21.tac-mb1a.tac-hb0b.5gstac.sos.epdg.epc.mnc012.mcc345.pub.3gppnetwork.org"