Telecoms have relied on least cost routing for years to drive the most cost-efficient handling of subscriber calls. In this process, they often relied on the LERG, otherwise known as the Local Exchange Routing Guide. While this routing guide has been the standard for a number of years, two forces are driving it into obsolescence.

According to this TransNexus (News - Alert) blog, the forces include a growing number of subscribers porting this landline telephone numbers to cable and wireless service providers, and the growing prominence of the North American number portability database to support least cost routing efforts.

Since it was mandated by the Federal Communications Commission in 1996, number portability has been a key issue for telephone companies. The percentage of calls to ported numbers is approaching parity with calls to un-ported numbers, making number portability a serious issue for enterprises and VoIP service providers. According to TransNexus customers, as of 2010, roughly 40 percent of their VoIP calls are to ported numbers.

Least cost routing is based on the dialed telephone number. When that number has been ported to a different carrier, routing the call directs it toward the carrier that owns the number, not the carrier actually serving the subscriber. The call can be completed, yet the termination cost can be greater than expected. Most long-distance providers will charge for wholesale termination based on the final carrier and not the dialed number.

TransNexus customers have reported rate differences between dialed and ported numbers can increase termination costs by a minimum of 15 percent, eliminating the benefits normally associated with least cost routing. The problem is expected to only get worse as more people port their numbers. To manage costs, you will have to route based on the Location Routing Number (LRN).

The creation of the Number Portability Administration Center (NPAC) was mandated by the FCC (News - Alert) to manage the database of ported numbers in the U.S. This list of 300 million ported telephone numbers and their corresponding LRN should be used to drive least cost routing, whenever possible. Initially, access to the NPAC was expensive and available only to telephone companies. Today, subscriptions are affordable for enterprises and VoIP service providers seeking least cost routing and number portability correction.

TransNexus helps in the least cost routing process by offering a SIP-based Linux software package that will reduce the cost of hosting the NPAC. The company anticipates that within five years, virtually all enterprise call centers and VoIP service providers will host the NPAC in their operation to drive true least cost routing. To find out more about TransNexus, visit the company at ITEXPO West 2011. To be held Sept. 13-15 in Austin, Texas, ITEXPO (News - Alert) is the world’s premier IP communications event. Visit TransNexus in booth # 819. Don’t wait. Register now.

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