10 Other considerations

23.2793GPPCombining Circuit Switched (CS) and IP Multimedia Subsystem (IMS) servicesRelease 17Stage 2TS

10.1 Handover

– Handover from DTM GERAN or UTRAN to non-DTM GERAN
If, during a simultaneous IMS session and CS call between two end-users, one of the end-users makes an intersystem handover into a non-DTM GERAN access, in this case the data traffic on the PDP contexts are handled as per procedures described in TS 23.060 [10].

– Handover from non-DTM GERAN to DTM GERAN or UTRAN
When a UE is participating in a CS call and not able to operate in Class A mode of operation, the UE cannot perform IMS capability exchange procedures. When the UE is again able to operate in Class A mode of operation, the UE can perform the IMS capability exchange procedures during the CS call, if required according to procedures outlined in clauses 7 and 8.

10.2 Relation to SMS

A user should be able to send or receive SMS during an ongoing CSI session. SMS is in general treated independently from CSI.

Annex A (Informative):
Support of CSI origination towards IMS termination with CSI interworking