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Routing Table Challenges in Least Cost Routing


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August 04, 2011

Routing Table Challenges in Least Cost Routing

By Tammy Wolf, TMCnet Web Editor

Over the years, major developments in telecommunications have severely increased the complexity of least cost routing, or the process of selecting the path of outbound communications traffic based on the most affordable cost, for the North American telephone network.

Many of these challenges are driven by commercial and regulatory requirements, including the emergence of a more complicated routing table size, thanks to wireless services growth, dwindling number blocks, and the FCC (News - Alert) requirements that came along with it.

A blog post by Jim Dalton, founder and CEO of least cost routing provider TransNexus (News - Alert), outlines how this change came to be for number blocks, or the first six digits of a telephone number.

When area codes were first established in 1947, there were a total of 78 area codes throughout the U.S. While only 36 area codes were added over the next 43 years, this number exponentially grew in the 1990s, when 109 new area codes were added to accommodate the new blocks of 10,000 numbers issued to carriers.  

The FCC, of course, was then faced with a diminishing supply of telephone numbers for new carriers to issue to subscribers. Therefore, they ordered in 2000 that NPA (News - Alert)-NXX blocks (NPA being the area code, and NXX being the switch code) be split into 1000 blocks (NPA-NXX-X). While this partitioning, also called number pooling, exponentially increased the supply of new numbers for growing carriers, this seven-digit routing system was deemed more complicated than routing six-digit blocks.

As of 2010, there were 166,431 six digit NPA-NXX dial codes, and 644,327 dial codes for routing seven-digit 1000 blocks in the Local Exchange Routing Guide.

According to Dalton, a dial code in a telephone routing table matches with a destination. This is then called a translation. So, with the majority of least cost routing tables providing an average of three destinations per dial code, this amounts to basic optimized least cost routing tables for U.S. domestic routing having more than one and a half million translations.

Of course, all of these changes over the years have resulted in the necessity for streamlined routing processes. That’s where companies like TransNexus come in to help organizations achieve new profits through the implementation of least cost routing.

To find out more, visit TransNexus’ website or bookmark the Least Cost Routing channel, exclusive on TMCnet.

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. 

Tammy Wolf is a TMCnet web editor. She covers a wide range of topics, including IP communications and information technology. To read more of her articles, please visit her columnist page.

Edited by Jamie Epstein

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