A.1 General structure of the SS stage 3 diagrams

24.0103GPPGeneral AspectsMobile radio interface layer 3Release 17Supplementary services specificationTS

In the SS stage 3 diagrams the messages that correspond to the normal case with successful outcome are shown using solid arrows. Messages for exceptional, or unsuccessful cases are shown using dashed arrows. In general, the diagrams show the initiating operation together with all possible outcomes. Obviously, in practice only one of the possible outcomes shown in the diagrams will occur when the operation is used. An example is given in figure A.1.

MS Network

Initiating Operation

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Normal, Successful Outcome

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Unsuccessful Outcome 1

<- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

Unsuccessful Outcome 2

<- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

Figure A.1: Example of the general structure of the SS stage 3 diagrams

A.1.1 Exceptional release procedures

To prevent transactions being kept open following exceptional cases, either side of the transaction may release it by sending a RELEASE COMPETE message without a Facility IE. This procedure can be used to release any call independent SS procedure, at any time while supplementary service support is established. For clarity this is not shown on the specific diagrams in the 3GPP TS 24.08x and 24.09x series, though it is still available.

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RELEASE COMPLETE

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‑ or ‑

RELEASE COMPLETE

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Figure A.2: Exceptional release procedures