What is a MSISDN number?

MSISDN is Mobile Subscriber Integrated Service Digitel Network. ITU-T ( International Telecommunications Union) that defines some numbering plan to the ISDN networks, Data networks and it also defines the format of Telephone Numbers.

Simply you can say MSISDN is nothing but it is your telephone Number.

Mobile Subscriber ISDN is the standard international telephone number used to identify a given subscriber. The MSISDN is the telephone number of a GSM (Global System for Mobile Communications) cell phone that is stored in the SIM (Subscriber Identity Module) smart card inside the phone. A public user identity in IMS is the equivalent of the MSISDN in a GSM network. Example:

+919-123-4567

(919)-155-4567

0113 272 2245

0044 113 272 2245

+44 113 272 2245

When requesting IMSPublicIdentity or ChargingInformation either the public_user_identity or msisdn parameter is required.