Number portability has been an issue for telephone companies since it was mandated by the FCC in 1996. Now number portability is becoming a serious issue for enterprises and VoIP service providers as the percentage of calls to ported numbers is approaching parity with calls to un-ported number. Our customers tell us that approximately 40% of their VoIP calls are to ported numbers.

Before LNP was established, the NPA-NXX of a telephone number identified the switch serving the number, the state and rate center where the number was originally assigned as well as the service provider. Because LNP allows a number to be moved from one switch to another, the NPA-NXX of a telephone number is no longer a reliable indicator of the serving switch and service provider’s identity.

If you want to manage your costs, you have to route based on the LRN, up to 40% of your calls are being incorrectly routed and priced! This can add up to huge financial losses for misrouted calls.

There is three common solutions:
1. XML query to LNP provider.
2. SIP request to LNP provider.
3. Hosting of the LNP Database locally. (sync your DB on certain times with third party LNP DB).
Obviously first two solutions will introduce extra delay in your system since extra request need to be made to third party provider for each call. This is usually the part of one routing engine which introduce the huge portion of your system PDD (post dial delay). The third solution is the fastest, especially if performed with NoSQL DB. But here you may end up with old and not accurate info.
If you do a lot of calls you should consider the third solution, beside speed this would save you money as well (each LNP query to provider costs you).

From where to get LNP data? The FCC mandated the creation of the Number Portability Administration Center, or NPAC, to manage the database of ported numbers in the U.S. In simple terms, the NPAC is a list of 300 million ported telephone numbers and their corresponding LRN. For every call, telephone carriers query the NPAC with the dialed telephone and receive the corresponding LRN needed for call routing. Companies such as NeuStar offer the complete NPAC available for download.

I know this sounds confusing, and your PBX might not be able to query the LNP. Call Center Pros™ has carriers that do the LNP query and will take advantage of the cost savings and pass that savings to your contact center.