Vendor Network Architectures�Part XLI: VocalTec Communications

VocalTec Communications, Inc. is known as one of the true pioneers of converged networking technologies. The firm was incorporated in Israel in 1989, and has been involved in the VoIP marketplace since 1994. One of its earlier products was a web-enabled call center, which was spun off as a separate company in 2001, called Surf & Call Solutions, Ltd.

Since that time, VocalTec has developed trunking, peering, access gateway, and service delivery solutions that are used by many leading carriers, including Deutche Telekom and Telecom Italia San Marino, providing a smooth migration of customer’s voice networks from Time Division Multiplexing (TDM) to Asychronous Transfer Mode (ATM) to the Internet Protocol (IP) technologies. In 2005, VocalTec joined forces with Tdsoft, a leading provider of VoIP gateways, and continued to focus their attention on providing carrier-class multimedia and VoIP solutions to communication services providers.

VocalTec’s products are designed for easy integration in multi-vendor environments, and handle media processing, signaling security, and service creation within next generation networks. These solutions are part of VocalTec’s Essentra product line, and are based upon the Session Initiation Protocol (SIP), but are engineered to support a number of protocols, including H.323, MEGACO/H.248, and the Media Gateway Control Protocol (MGCP). The Essentra architecture consists of four key elements:

  • Essentra CX: is a core control softswitch that allows legacy trunking networks to migrate their systems to next-generation environments, while allowing VoIP providers to connect their networks to the Public Switched Telephone Network (PSTN) and its Signaling System 7 (SS7) environment. The Essentra CX can be configured in two ways: as a distributed solution where the signaling and PCM (Pulse Code Modulation) trunking are handled separately; or as an SS7-enabled SIP gateway which integrates both the signaling and media gateway functions. The Essentra CX includes intelligent call control, an advanced routing engine, and PSTN SS7 support, providing both control interworking functions for smoother migration to next generation environments.
  • Essentra EX: As more carrier networks deploy VoIP for both trunking and enterprise connections, the need for interconnection between these networks increases. A peering manager, which facilitates the requirements for protocol interworking, accounting/billing, and routing between SIP and/or H.323 networks is thus required. The Essentra EX provides these peering functions, and can be deployed with any VocalTec or third-party softswitch platform. The system provides enhanced call routing capabilities to maximize network performance and reduce transport costs. In addition, a SIP-based service layer is provided which hides all of the service/routing logic and network topology information from the routing layer, which simplifies the network management overhead.
  • EssentraGate: Not all subscribers will migrate simultaneously to a next generation network—a transition time will be required during which different network access methods, including digital loops, fiber optics, and cable will be in use. In North America, the GR-303 interface, defined by Telcordia Technologies (formerly Bell Communications Research) is frequently used as an access protocol for TDM-based networks. The EssentraGate product provides that access gateway, assuring that the network connectivity, signaling, codec selection, echo cancellation, silence suppression, and other key operations pass from the existing network to the IP-based infrastructure.
  • Essentra BAX: One of the key financial premises of converged networks is their ability (or the promise of the ability) to provide broadband services, such as video on demand, online gaming, multimedia conferencing, and other bandwidth-intensive applications. However, there is still a market for enhanced voice services, which can generate positive cash flows for carriers while the more exotic broadband applications are being developed and deployed. The Essentra BAX Broadband Access Server is designed to provide a broad range of subscriber calling features that can take advantage of new revenue-generating opportunities. These include subscriber calling features such as call waiting, call forwarding, caller ID, and 3-way calling; and IP Centrex features including private numbering plans, music on hold, call park/pickup and billing codes.

Further details on the VocalTec architecture and products can be found at Our next tutorial will continue our examination of vendors’ architectures.

Copyright Acknowledgement: © 2006 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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