BroadSoft, a provider of VoIP applications to telecom service providers, this week said it acquired competitor Sylantro Systems for an undisclosed sum.

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BroadSoft provides VoIP application software designed to enable service providers to deliver hosted telephony and multimedia services to businesses and consumers. It recently aired a hosted unified communications service in conjunction with Microsoft.  

Sylantro offers server software for hosted IP communication services across fixed, mobile, and cable networks. Sylantro's Synergy and Web services software provide a platform for creating converged services for businesses and consumers (Sylantro recently announced compatibility of its Synergy platform with Amazon Web Services' Elastic Compute Cloud.)

BroadSoft acquired Sylantro to eliminate a competitor and build its market position in VoIP applications. BroadSoft provides VoIP applications to eight of the top 10 and 14 of the top 25 largest carriers worldwide, including Korea Telecom, KPN, SingTel, Sprint, Telefonica de Espana, Telstra, T-Systems and Verizon.

Sylantro customers include AT&T, China Netcom, QWEST and Swisscom, among others.

BroadSoft said it intends to support Sylantro's Synergy platform through its direct sales force and authorized Sylantro and BroadSoft partners.

Industry watcher Om Malik writes on Gigaom that he understands no cash passed hands in this deal, and that BroadSoft assumes Sylantro's debt. BroadSoft has raised more than $76 million in venture funding, while Sylantro has collected in the neighborhood of $116 million.