Is there a session border controller in your enterprise's VoIP future? If you're looking to expand your organization's VoIP reach - to VoIP-based service providers, to other enterprises or even to VoIP-interconnected distributed sites via the Internet - there very well may be.

Functionally, an SBC is a traffic cop: It facilitates and mediates VoIP flows in real time, in both directions between private VoIP domains: an enterprise and a VoIP-based service provider - the environment we tested here - or two service providers. SBCs came of age by providing peering connectivity between different carriers' VoIP services and only recently have begun penetrating enterprises.

There is no universal job description for an SBC. Certainly there has to be versatile handling of VoIP call-control protocols, such as Session Initiation Protocol (SIP) and H.323, especially amid different firewall and network address translation (NAT) configurations. And there needs to be some security safeguards - hiding the network topology of the private network, for example. But overall, SBCs are complex and costly components, coming from diverse backgrounds and offering widely varying capabilities.

We invited more than a dozen vendors who were touting new SBC wares earlier this year to submit their packages for testing in Miercom's New Jersey lab. Four accepted our challenge for this feature-based testing: Ditech Communications, Ingate Systems, Mera Systems and NexTone Communications.

Despite many differences in the feature sets of these products (see "What SBCs do"), their general orientations lie in a few similar, basic areas, including VoIP call handling, QoS handling and security capabilities. Based on our assessment in these areas, our Clear Choice Test Award goes to NexTone's package, the Multiprotocol Session Controller (MSC) coupled with its iView Management System (iVMS). NexTone's dynamic VoIP session control, real-time monitoring with active error and threshold-limit notification, call-level reporting system, and integrated firewall features make it the best of the enterprise-focused SBCs we tested. We note, though, that the NexTone package costs considerably more than the competition (more than $100,000, compared with $25,000 to $38,000 for the others).

Next: NexTone Communications >