6.3 Coordination between SM and GMM for supporting ISR

24.0083GPPCore network protocolsMobile radio interface Layer 3 specificationRelease 18Stage 3TS

The MS with its TIN set as "RAT‑related TMSI" for which ISR is activated shall change its TIN to "P-TMSI" to locally deactivate ISR and stop the periodic tracking area update timer T3412 or T3423, if running:

– upon modification of any PDP context which was activated before the ISR is activated in the MS;

– upon deactivation of the last remaining PDP context in the MS;

– at the time when the MS performs intersystem change from A/Gb mode to S1 mode or from Iu mode to S1 mode if any PDP context activated after the ISR was activated in the MS exists, and the MS is in EMM-IDLE mode on completion of intersystem change; or

– upon deactivation of last non-emergency PDP context in the MS, if the MS has only a PDN connection for emergency bearer services remaining.

ISR remains activated on the network side in the above cases.