Local Number Portability (LNP) is possible thanks to the Location Routing Number (LRN), a unique 10-digit telephone number assigned to each switch.
Prior to the establishment of LNP, a telephone number’s original state, rate center, service provider and carrier type (wireline, wireless, or VOIP) were identified in the North American Numbering Plan (NANP) by the NPA (area code) and NXX (central office code). With the introduction of LNP, telephone numbers were being ported between service providers and a new way of determining the network address of the serving switch was needed to ensure the call was routed correctly. With that, the LRN was created.
The LRN is a unique 10-digit telephone number assigned to each switch to support call routing through the public switched telephone network (PSTN). It serves as the network address and includes the NPA and NXX for a telephone number. A single LRN can be used for every ported number served between a switch and the NPA-NXX assigned location. The assignment of an LRN allows for LNP.
There are three reasons a telephone number might need to be ported:
Each telephone number entered into the NPAC’s records, is called a “Subscription Version” and contains the following information:
The entire porting process can take just minutes. The FCC has mandated simple one-number port requests be completed within one business day.
A call is made to a ported telephone number