ITU-T Recommendations

A plan for unique international identification of mobile terminals and mobile users is required in order to enable these terminals and users to roam among public networks which offer mobility services. International Mobile Subscriber Identity (IMSI) is required so that a visited network can identify a roaming mobile terminal or mobile user, e.g., in order to query a subscriber's home network for subscription and billing information.ITU-T Rec. E.190 describes the general principles to be utilized in the assignment of ITU-T E-series international numbering resources. The procedures in this Recommendation were developed in accordance with the principles contained in ITU-T Rec. E.190, and the statements contained in ITU-T Rec. E.190 take precedence over this Recommendation.