The VoIP Peering Puzzle�Part 10: The SPIDER Registry

Our last peering tutorial reviewed NetNumber’s TITAN (Transactional IP-Telephony Addressing & Numbering) service, which provides an addressing server infrastructure for next generation carriers (see The TITAN specifications state that one of the ENUM services that TITAN can be configured to receive is data from the SPIDER Registry. So let’s see if we can untangle this web, and understand more about the SPIDER Registry.

NetNumber, Inc. and Arbinet-thexchange, Inc. an electronic trading marketplace and VoIP peering consortium, launched the SPIDER Registry, Inc., an acronym that stands for Service Provider ID E.164 Record, in May 2006. SPIDER was formed as a non-stock, not-for-profit entity, governed by a board of directors representing Internet Protocol (IP) industries from around the globe. SPIDER is also neutral, in that the registry database services are made available on an equal-access basis to any registrar that wants to utilize the registry‘s tools. Service providers that choose to utilize solutions based on SPIDER may purchase interconnect services from any number of competing solutions providers.

So what’s in the web? In short, SPIDER is a registry of registries—a database where service providers register and then exchange their E.164 addressing records with trusted interconnection partners around the globe. When a telephone number is dialed, the SPIDER registry goes about answering the question: “Which of my trusted interconnect partners and/or trusted intermediaries is capable of terminating traffic to this number?” Thus, SPIDER provides a shared VoIP registry infrastructure and thus enables the efficient exchange of interconnect addressing data between the many islands of VoIP.

The SPIDER registry database services are offered exclusively via registrars, and are made available on an equal-access basis to any registrar that wants to utilize the SPIDER tools to enhance its interconnect services. The registrar services are typically delivered by VoIP interconnect solution providers, although membership is open to any organization, including enterprises, government agencies, or higher education institutions, that have an interest in the interconnection of IP services.

SPIDER provides a secure, publicly available Simple Object Access Protocol (SOAP/XML) application programming interface (API) to enable registrars to create and administer SPIDER accounts and provide SPIDER services to their communication service provider customers. The registrars then configure the registry to distribute data to downstream addressing servers operated by service providers and/or other intermediaries. Note that SPIDER does not provide any ENUM or SIP-redirect address resolution services, and does not provide any interconnect services. SPIDER is much more focused than that: It provides the shared database tools that are necessary to exchange interconnect addressing data between trusted partners, and then bills each registrar for the use of the SPIDER data associated with its accounts.

So how does the SPIDER spin its web? Let us envision two VoIP communities, each with its own addressing servers, which are served by the SPIDER process. A SPIDER registrar has provisioned the interconnect data (E.164 numbers, etc.) from its customer (a communications service provider). Account administration and provisioning information is then sent from that registrar via the SPIDER SOAP/XML API to the SPIDER registry. SPIDER data, which has been customized and approved for distribution to that particular account, is then returned from the SPIDER registry to the addressing server within each VoIP community. A communications application would then query its addressing server (which could be an ENUM server or a SIP location server). If the query succeeded in returning addressing data, a report would be made to the SPIDER registry, which would in turn trigger a bill to be rendered for those services.

Three different billing models are available:

  • a successful query fee, on a per-usage basis
  • a monthly fee, for each subscriber supported by a service-provider account holder
  • a flat rate fee, for account holders that want unlimited use of the SPIDER data

After only six months in operation, some of the largest providers have signed on to become SPIDER members, including Arbinet and VoEX, Inc., the Voice Exchange. The registry presently holds 115 million numbers, representing 52 million active subscribers. Further details on the SPIDER architecture are available at

Our next peering 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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