This article originally appeared in the January 2011 issue of INTERNET TELEPHONY

ITEXPO (News - Alert) East 2011 will be in Miami in February. For the past couple of years one of the dominating themes at the ITEXPO events has been SIP trunking. The message is getting through, but still too slowly. There is no advantage whatsoever to sticking with circuit-switched connections for voice systems. Reliability and security are simpler with circuit switched, but they are easily addressed on IP voice systems, and the benefits to be gained from going all IP are vastly greater than the downside. Circuit-switched voice access is equivalent to a system that converts all your e-mail traffic to faxes for delivery to your users.

All IP can give you a unified voice and video communications network, and it can give you HD voice at a lower cost than circuit-switched voice. 

There are several ways to address the reliability issue, depending on your setup. The Internet way is redundancy rather than bomb-proofing a single system. This means for general office work the simplest way to go is to have your hosted extensions roll over to cellular numbers on no answer. This way your entire building can lose power and your phone service remains uninterrupted. For call centers this obviously doesn’t work, but call centers have to have uninterruptible power and network access in any case, so the voice systems can simply piggyback on that.

For security it is hard to beat a circuit-switched access link – by costing the caller money it eliminates a large category of spam calls, and by eliminating IP it eliminates most network vulnerabilities, though circuit-switched connections are still vulnerable to service theft. But the downside to circuit-switched connections is far greater than their benefits. Conventional firewalls are inadequate for VoIP security, which demands deep packet inspection. This is done by session border controllers. According to Infonetics, the market leaders for enterprise SBCs are Acme Packet and Cisco (News - Alert). Vendors specializing in the enterprise market include Ingate, AudioCodes and Sipera.

Michael Stanford has been an entrepreneur and strategist in VoIP for more than a decade. (Visit his blog at www.wirevolution.com.)