What is session transfer number for SRVCC in delete subscriber data?when this will be sent to mme?

Question

In Diameter S6a specification (3GPP 29.272), it is indicated that the full procedure for Delete-Subscriber-Data from the HSS should be described in the 3GPP 23.401
However, I don't see any clear reference there.
Do you know where I can find it, especially for the deletion of one of the APN-configuration in the MME

Answer 1

Its a number which MME stores the STN-SR (Session Transfer Number for SRVCC) along with C-MSISDN of the UE from the HSS during the UE attach procedure.

Comments

will you tell the purpose of this IE

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- Per TS 24.237 the STN-SR is assigned to the SCC-AS/ATCF
- For the case where the SRVCC is enhanced with the use of the ATCF, the STN-SR is used to direct signaling towards the ATCF, otherwise it is used to direct signaling to the SCC AS per TS 23.237
- According to TS 23.003, STN-SR follows the E.164 telecommunications number format
- It is used by the MSC for session transfer of the media path from the PS domain to the CS Domain
- The STN-SR is provisioned in the HSS as part of the subscriber profile information to indicate that the UE is SRVCC capable (TS 23.216)
- If the STN-SR is updated from the value that is in the HSS, then the SCC AS updates the HSS which in turns updates the MME