//Publication Date: 02/13/2025_

CLEC formation - overview

The genesis of this article was my attempt to answer what I, at the time, thought would be a straightforward question: “If IP addresses come from ARIN and get routed through BGP-peered ASNs, where do phone numbers come from, and how are they routed?” The answer to this question turned out to have been not so simple after all. What I didn’t know then, and what I would come to learn over the next two years, is that learning the answer to this question and then actually completing the process of obtaining numbers to completion would turn out to be one of the most complex legal and technological feats possible, easily eclipsing becoming a publicly peered ASN and purchasing and setting up a mainframe, and perhaps only secondary to creating a chip fab in your garage (which I also hope to do someday). If you read the rest of this article series, you will learn in detail how the US phone system works, how it’s regulated, and how to operate within it. Should you decide to attempt this process and follow it all the way through to completion, you will achieve a thing that less than 2,000 other US operations can claim to have done and have full access to the US telephone network as a legally declared peer carrier to AT&T, Verizon, and CenturyLink (aka Lumen aka Brightspeed aka whatever they’re calling themselves this week), giving you the ability to directly open up your own telephone number blocks, directly route your calls using the LERG, and directly interconnect with the major carriers, and a host of other interesting, nerdy features.

The complex overlapping between regulatory, technical, and corporate issues makes this process uniquely difficult. In order to even get started in the first place, you must obtain a Certificate of Public Convince and Necessity or CPCN (This is the name in most states, though some use Certificate of Authority or something else altogether), a state certificate that allows you to operate as a telephone company. In most states, this can require 100+ pages of paperwork and deep knowledge of the regulatory terminologies and requirements in order to be approved by the state commission or Administrative Law Judge (ALJ) hearing the case. In addition to this procedural roadblock, many states also have capital and management experience requirements, which can further hamper your success in the process. Understanding the distinction between the state and federal certification types and how to file for each will be part 1 of this series.

The next challenge is the confusing layout of the PSTN as a whole. Unlike IP networks, where routing tables are built dynamically with minimum manual overhead to establish and sync new paths, PSTN routes are built manually, based on several expensive routing codes used to denote switches, companies, and many other things. These disparate elements are used to compile a set of master source of truth CSV files that dictate the correct routing for the whole phone network (no, this is not a joke), distributed to individual carriers to build their routing tables. The network typically takes 30-60 days to converge new changes. Automatic path selection and routing is only possible within a single carrier’s network, and even this is not universal. Part two of the series will cover the different government agencies, NGOs, and private companies responsible for maintaining different segments of the network information and the process of obtaining and activating a new block on the network, along with the structure and design of the PSTN and its routing.

Once you have obtained codes and understand how number blocks are obtained and built, the next hurdle to overcome is building a switch that is compliant with the needs of the public telephone network. Since your switch will control your end product, call quality, billing, routing, and almost everything else about the services you deliver, it’s essential to either buy something that meets your needs or have the technical know-how to build it yourself. Softswitch and VoIP network design can (and will) be multiple series on their own, so for this series, part 3 will stick to an overview of the major pitfalls that someone familiar with simple PBX designs might encounter when making the switch to carrier systems, and some of the commercial vendors that are available.

With certifications, codes, and infrastructure in place, you’re about three-quarters of the way done. With your network in good shape, you have to figure out how to get calls into it! Connectivity generally comes in two types and is from two different sources. Calls on the PSTN are either local or long-distance, and these are the two different types of connectivity that you will need for your network: regulated local interconnection for the rate centers that your numbers are technically local to and long-distance interconnection for literally everything else. In this context, regulated interconnect refers to formalized interconnection agreements between the post-divestiture incumbent telephone company and you, as mandated by the Telecommunications Act of 1996. It’s typically a massive pain in the rear to work with as it can only come from one of these incumbent companies, but it is required if you want full local call coverage in your area. The converse of this is long-distance interconnection, which will cover 99% of all of your inbound calls and for which you actually have a choice of which provider to use and can typically get it delivered over IP. Interconnection agreements, dealing with the ILECs, and other types of voice connectivity will be part 4.

With all of this in hand, you will have a fully interconnected, fully built-out CLEC network, but for one thing: STIR/SHAKEN. S/S is the caller ID authentication system that has been implemented to attempt to stem the massive tide of robocalls that have been inbound into the US phone network through IP-based trunks. S/S is another thing that could be its own much larger article, but only the basics are required to get in compliance with the FCC. S/S will be part 5. With all of these steps done, you’re finished! Your network will be fully compliant and fully built out for wireline services. This series will conclude with a brief overview of the mobile network and its systems, SMS, and some final thoughts. If all of this sounds interesting, then strap in, buckle up, and tune in next time for some high-octane legal research!