The aim of this Technical Report is to study and specify potential enhancements to the IMS architecture to enable IMS FE to integrate with the 5GC network functions to enable IMS applications to directly leverage the features and capabilities of 5GC.
The specific capabilities of 5GC included in this study include the PCC functionality required to resolve the key issue related to:
Network Slicing and IMS
Routing of IMS traffic via a localized UPF
The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
: "Vocabulary for 3GPP Specifications".
: "Study on enhanced IP Multimedia Subsystem (IMS) to 5GC integration Phase 2; CT WG1 aspects".
: "Study on enhanced IP Multimedia Subsystem (IMS) to 5GC integration Phase 2; CT WG4 aspects".
For the purposes of the present document, the terms given in TR 21.905
and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905
For the purposes of the present document, the following symbols apply:
For the purposes of the present document, the abbreviations given in TR 21.905
and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905
UE Route Selection Policy
Regarding the evaluation to solution #1, please refer to clause 7 of TR 23.700-10
Regarding the evaluation to solution #2, please refer to clause 7.1 of TR 23.700-12
Regarding the conclusion to key issue #1, please refer to clause 8 of TR 23.700-10
. As providing a new parameter "IMS home network domain name" in the traffic descriptor will be the basis for work in the normative phase, the URSP needs to be extended to enable a UE connects to two IMS networks through two 5GC network slices.
Regarding the conclusion to key issue #2, please refer to clause 8.1 of TR 23.700-12
. This solution proposes to convey the UPF service area for the IMS PDU session from SMF to PCF and on to P-CSCF during multimedia session establishment. The PCF either stores the UPF service area as part of the SM policy or fetches the UPF service area from the SMF when requested by P-CSCF. PCF may also subscribe to a new event "UPF service area change" upon establishment of the SM policy association.