Vendor Network Architectures�Part LIX: Dialexia Communications

Dialexia Communications, Inc., of Montreal, Quebec, was founded in 2001 as an Internet Telephony Service Provider (ITSP) with a focus on SIP-based telephony solutions. Today, the company has expanded beyond that initial objective to offer a complete range of communications solutions to address their customers’ business communications needs.

Dialexia provides products in four areas: single- or multiple-server SIP-enabled VoIP platforms that integrate voice, data, and video on a single network; IP-based PBX with PC-based softphones; advanced text-to-speech and voice recognition-enabled interactive voice response solutions; plus a comprehensive suite of customer, system, accounting, and administration tools.

Dialexia’s solution for the small and medium business market, Dial-Office, is a fully featured communication server based entirely on SIP standards. In addition to providing PBX features typically found only on much larger systems, the Dial-Office system is interoperable with a number of third party phones, gateways, and other adjunct systems. The system is configured for two different capacities: a small version, supporting 10 to 50 extensions, and a medium version, supporting 50 to 150 extensions. The Dial-Office code is based on Java, and runs on a Windows or Linux-based PC.

Dial-Office has a modular architecture and consists of the following key components:

  • Dial-Manager: a SIP-based proxy that enables real-time communication over IP networks. This component includes three fundamental SIP components: a SIP Proxy server, a SIP Registrar server, and a Presence server.
  • Dial-Media: an IP-based media server that runs dynamic Interactive Voice Response (IVR) applications that are based upon extensible markup language (XML) technology. This module features seamless voicemail and media services such as call park and call relay, plus IVR functions for voicemail and automated attendant. In addition, the Dial-Media component can integrate third-party media technologies such as text-to-speech and voice recognition, thus providing additional productivity tools to the end users.
  • Database: a centralized database collects and stores significant call information, including the Dial-Manager and Dial-Media provisioning data, user settings, SIP session information, call detail records, server logs, and error/alarm logs.
  • OA & M Interface: a web-based operations, administration, and maintenance (OA&M) tool provides access to the Dial-Office database, enabling the configuration of user profiles, routing and rate tables, and the IVR engine. In addition, this interface allows call traffic statistics to be monitored, gateways and domains to be configured, and web access to be managed.

The Dial-Office system also includes some optional modules to enhance office productivity, including:

  • Automatic Call Director: The ACD manages heavy incoming call volume, and deploys a call transfer distribution process based upon three different priority policies: first idle extension, most idle extension, or circular call transfer.
  • Integrated voicemail: This includes administratively definable user storage limits and profiles, as well as voice messages saved as .WAV files—so that users can access, save delete, and forward voicemail through phone or other file sharing methods such as e-mail.
  • Failover support: This reliability solution is used for large systems with more than 300 extensions. Two machines are dedicated to hosting the Dial-Office application, the first as the master, and the second as a backup, which takes over call processing operations if the master fails.

In addition, the Dial-Office system supports Network Address Translation (NAT) and firewall environments, for enhanced security for remote users. Further details on the Dialexia products and architectures can be found at Our next tutorial will continue our examination of vendors’ architectures.

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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