The following is an excerpt from the 3GPP 23.066:
Mobile Number Portability information: an information set relevant to Mobile Number Portability for a mobile subscriber. It may contain one or more of Routeing Number, generic IMSI, MSISDN,and Number Portability Status.
Here are my questions:
It is mentioned that the NPDB contains the Number Portability Status. I find it difficult to understand the necessity of the it.
Isn't it implicitly understood that if the subscriber is located in the NPDB, it is meant as the subscriber is ported-out and it is 'Number Portability Status=Yes', always.
I do not find a usecase for the subscriber entry located in the NPDB and the Number Portability Status is set as 'No'. Why is it necessary?
I could understand that the query should be forwarded to the HLR, if the subscriber entry is not located in the NPDB. If the same handling is necessary even for 'Number Portability Status=No', why should the NPDB maintain this state at all?
In my understanding, there is a 1:1 relation between the ported-out MSISDN and the 'Routeing number'. But, the specification says 'one or more Routeing Number'. Is that really the case?