Page 406 - 5G Basics - Core Network Aspects

1 Core network aspects

Figure 9-1 – Enriched call composition

1) MUE1_IF(1) sends a SIP SC1 invite (service compose message, SDP audio session) to SCF1(1) to
create SC1 component.

2) MUE1_IF(2) sends a SIP SC2 invite (SDP video session) to SCF1(2) to create the SC2 component.
3) SCF1(1) forwards the SIP SC1 invite message of SC-1 to MAS-F.
4) SCF1(2) forwards the SIP SC2 invite message of SC-2 to MAS-F.
5) MAS-F obtains related information (such as the equipment that the messages come from, the
applications that the messages belong to, etc.) from MUP-FE, and decides whether the components
(SC-1 and SC-2) can be composed.
6) MAS-F identifies that the requests belong to the same call and can be composed. MAS-F combines
SC-1 and SC-2 as SC-3.

7)-9) The SIP invite of SC-3 is routed to an SCF1(2), which is SCF1(2) in the figure, but which may also be
another proper one. Then the SIP invite is forwarded to UE2. UE2 can be a multi-connection UE or
an ordinary UE.
10) UE2 accepts the call, but indicates that it would not want to send video back.

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