Switching to VoIP

This is the Title of the Book, eMatter Edition

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Regulation and Organization of the PSTN

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So Q.931 is a signaling protocol recommendation, while E.164 is a recommendation

for a numbering scheme used for international dialing. V.90 is a modem communica-

tion recommendation, while H.248 is a media gateway signaling standard. A library

of these standards is maintained online by the ITU-T. The service providers who are

most directly affected by, and who most frequently use, all of these recommenda-

tions are the companies that operate the PSTN: RBOCs, CLECs, IXCs, and LD

carriers.

RBOCs and CLECs

Regional Bell operating companies, or RBOCs, are the largest of the local phone ser-

vice providers. These are the companies that tend to own most of the cabling infra-

structure in areas that are routinely as big as an entire state. They are sometimes

referred to as incumbent carriers because most of them got their start as a part of a

huge, national corporation called AT&T that was once in charge of the national tele-

phone system. In the early 1980s, that company was disbanded and broken into

many smaller regional Bell operating companies.

RBOCs are also called ILEC, or incumbent local exchange carriers—

because they were around before CLECs were introduced by deregula-

tion.

Competitive local exchange carriers, or CLECs, are local telephone ...