The VoIP Peering Puzzle�Part 13: Telcordia’s Service Interconnection Registry

Telcordia Technologies, Inc. headquartered in Piscataway, New Jersey, is a leading global provider of telecommunications network software and services for IP, wireline, wireless, and cable infrastructures. The Telcordia organization may be better known by its former name, Bell Communications Research, or Bellcore, which was created in 1984 as a result of the breakup of the Bell System. Bellcore was jointly owned by the (then) seven Regional Bell Operating Companies (RBOCs), and was responsible for research and development plus standards activities in support of those companies. Bellcore was sold in 1997 to Science Applications International Corporation (known as SAIC), which changed the name to Telcordia. In 2004, the firm was sold to a group of investors, which has subsequently maintained the firm’s focus on telecommunications research.

Telcordia primarily serves wireline, mobile, cable, government, and equipment supplier markets around the globe with a robust portfolio that includes operations support systems (OSS), network services software, consulting and testing services, and research services. The company’s depth and breadth of experience is evident in products that touch nearly every corner of telecommunications, with research that has led to ADSL, ATM, Frame Relay, SONET, AIN, ISDN, and many other industry breakthroughs. Today, Telcordia software handles 100 percent of the United States toll-free traffic and holds a 90 percent market share of wireless number portability in the U.S.

Telcordia has leveraged its strong background in addressing and routing technologies for both the PSTN and IP-based networks, with its Service Interconnection Registry product, formerly known as the VoIP Routing Registry. This solution optimizes routing administration for PSTN-to-PSTN, PSTN-to-VoIP, VoIP-to-PSTN and VoIP-to-VoIP calls. The product is part of the Telcordia’s Maestro™ IP Multimedia Subsystem (IMS) Portfolio, which is designed to enable any service, over any network, to any device. (see

The Service Interconnection Registry offers a trusted, secure, carrier-grade registry that enables service providers to smoothly migrate from TDM to IP—as well as enabling cross-service-provider delivery of new, revenue-generating converged services. In North America, the Service Interconnection Registry is operated by Telcordia Routing Administration, which manages the Telcordia Local Exchange Routing Guide, or LERG, a database of telephone area code and exchange codes (NPA/NNX) published by Telcordia, and used by interexchange carriers to route calls over the PSTN. The Service Interconnection Registry includes three independent but inter-working modules: Global Dialing Data, TDM Service Interconnection, and IP Service Interconnection.

The Global Dialing Data module provides the most comprehensive database of global dialing data information, including dial codes and their associated service provider, service type, and geographical locations. It contains more than 750,000 dial codes in over 230 markets. The TDM Service Interconnection module enables service provider interconnection via TDM facilities. The IP Service Interconnection module (formerly known as the VoIP Routing Registry) enables service providers to interconnect via IP, and deliver end-to-end IP-enabled services. It is a global product that supports the Domain Name System (DNS), the Session Initiation Protocol (SIP), and the full E.164 numbering space.

This IP Service Interconnection module offers a robust set of address features and capabilities, including:

  • A carrier-grade solution, which integrates the appropriate LERG data, facilitates a smooth migration to IP, and ensures the validity of the routing data—plus the ownership of that data.
  • Support for IP services beyond VoIP, which offers service providers an efficient platform to manage all of their IP service routing administration needs.
  • A flexible routing infrastructure, in which service providers maintain different routing data for the same destination address (e.g., dialed number) to their interconnection partners, based on the service type, quality of service requirements, and business relationship with their individual interconnecting partners. Service providers can enter routing information on a telephone number basis or by a block of numbers, for ease of number management and administration.
  • Local number portability data, to ensure that the routing information has been corrected if the number has been ported.
  • Configurability for interoperability with other registries, as multiple ENUM registries will likely coexist in the foreseeable future, to provide the appropriate address resolution even if the data resides elsewhere.
  • Security and privacy, which permits only authorized parties to manage or access its data.
  • Flexible data access/distribution options for download in bulk, or to the service provider’s local server, or via a real-time query.

Further details on the Service Interconnection Registry architecture and other Telcordia addressing services are available at Our next tutorial will continue our examination of some of the commercial enterprises that are offering ENUM and other directory services.

Copyright Acknowledgement: © 2007 DigiNet Corporation®, All Rights Reserved

Author’s Biography
Mark A. Miller, P.E. is President of DigiNet Corporation®, a Denver-based consulting engineering firm. He is the author of many books on networking technologies, including Voice over IP Technologies, and Internet Technologies Handbook, both published by John Wiley & Sons.

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