local number portability (LNP)

Number portability( NP), local number portability (LNP) or wireless local number portability( WLNP) refers to the portability of a telephone number. In this context, the end subscriber has the option of retaining his original number despite certain changes to his network access.

Number portability makes particular sense in the event of a change of residence, change of network operator, or changeover from analog telephony to ISDN or Internet telephony, as the subscriber can retain his old number. In the first case, when there is a change of address, this is referred to as number portability; in the second, when there is a change of provider, it is referred to as network operator portability, and when there is a change of service, it is referred to as service portability. If portability depends on the geographical location of the network, it is Geographical Number Portability (GNP); if, on the other hand, the connection is not permanently identifiable, it is Non-Geographical Number Portability (NGNP).

The numbering space for Europe defined by the International Telecommunication Union( ITU), European Telecommunications Numbering Space ( ETNS), supports number portability.