J.5 ISR deactivation

23.4013GPPGeneral Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) accessRelease 18TS

Deactivation of ISR for the UE does not require any specific functionality. The status of ISR activation is refreshed in every RAU and TAU Accept message. If there is no explicit indication of ISR Activated in these messages then ISR is deactivated and the UE sets its TIN to "GUTI" or "P-TMSI", as specified in Table 4.3.5.6-1. This causes always ISR deactivation when a UE performs a RAU with a Gn/Gp SGSN of any standards release as these SGSNs never indicate "ISR Activated" to the UE.