Feature Description
The MME includes the Additional Mobile Subscriber ISDN (A-MSISDN) flag in the Features List AVP of the Update Location Request (ULR) messages that are sent over the S6a interface to the Home Subscriber Server (HSS) at the time a UE Attaches. In response, if an A-MSISDN is available then the HSS sends a provisioned A-MSISDN and an MSISDN in the Subscription Data AVP in Update Location Answer (ULA) and IDR messages.