Is it mandatory to have an MSISDN associated with a IMSI record on the HLR?

Question

M2M devices and data cards without voice services may not need an MSISDN, how are such records maintained on the HLR? Is it mandatory to have an MSISDN associated with every IMSI record on the HLR? If yes, can we just have a dummy/fake MSISDN associated in such a case so to avoid consuming/wasting a real MSISDN?

Comments

Adding my thoughts, not really an answer:

I agree your point for M2M devices where MSISDN would not be required as they can have IP connectivity alone. However a fallback to SMS channel if IP is not available can also be argued as need for MSISDN.

But for the evolving Datacard scenario, the operators are providing rich UI with the datacard where you can have personalized inbox to send and receive SMS, get usage stats, etc. It might be required to have MSISDN for datacards in such case.

It is however interesting to know if on a need basis the MSISDN can be re-used or have dummy MSISDNs.

Answer 1

The home location register (HLR) is a central database that contains details of each mobile phone subscriber that is authorized to use the mobile core network. There can be several logical, and physical, HLRs per public land mobile network (PLMN), though one international mobile subscriber identity (IMSI)/MSISDN pair can be associated with only one logical HLR (which can span several physical nodes) at a time.
Datacards, dongles do have the MSISDN/IMEI/IMSI so it should not be a problem, however in some case specially related with IMS these things may not be present in that case the database is not HLR rather something else.
In case fake MSISDN it is technically possible but why operator will like to do that???