Feature Description
The AMF provides the IP Multimedia Subsystem (IMS) voice services over the Packet Switched (PS) or VoNR to the subscribers who are connected over the 3GPP Radio Access Network (RAN).
AMF receives the local configuration and capability parameters from UE or gNB. Based on this information, the AMF determines if the UE can support the IMS voice over PS sessions in the specified area. The AMF communicates the IMS support to the UE during the UE registration process.
With this feature, the AMF extends support for the following:
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PDU support for same or different SMF instances
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Discovery of the SMF instances using Tracking Area Identity (TAI as the query parameter
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Reuse of the discovered SMF instances within the cache expiry timeout period
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If used within the cache expiry time out period, the PDU release and update procedure can utilize the SMF instance discovered for the PDU creation procedure.
Note | The NO_SUITABLE_CELLS_IN_TRACKING_AREA is used for rejecting the voice-centric cause. |