Mobile number portability (MNP) enables mobile telephone users to retain their mobile telephone numbers when changing from one mobile network operator to another. Mobile number portability is implemented in different ways across the globe. The International and European standard is for a customer wishing to port his/her number to contact the new network (recipient), which then sends the number portability request (NPR) to the current network (donor). This is known as "recipient-led" porting. The UK and India are the only exceptions to implement the donor-led system. The customer wishing to port his/her number is required to contact the donor to obtain a code (Porting Authorisation Code (PAC) in the UK and Unique Porting Code (UPC) in India) which is then given to the recipient network. The recipient continues the porting process by contacting the donor with porting code. This form of porting is known as "donor-led". A significant technical aspect of MNP is relat...