02.663GPPService descriptionStage 1Support of Mobile Number Portability (MNP)TS
Mobile Number Portability cannot be offered to a subscriber as a stand alone service. Mobile Number Portability is applicable to all GSM teleservices (e.g. SMS, voice fax) and bearer services (e.g. data), except for TS12 (emergency call).
The implementation of MNP shall be flexible enough to apply to each DN of a subscriber separately. Where the DNs used in the donor network are ported to different recipient mobile networks then a new IMSI (and SIM) will be required for each recipient network. The basic and supplementary services provisioned in the recipient network shall not be dependent on those that were provisioned in the donor network.