DiVitas handles wireless network hops with aplomb

Around the lab, DiVitas's wireless tech has taken on a legend similar to that of Sasquatch: Many have claimed to see it, but no one's been able to confirm it for the official record. Until now. DiVitas finally made the arduous journey from Silicon Valley to Honolulu for some hands-on testing at the Advanced Network Computing Lab at the University of Hawaii.

[ The DiVitas Mobile Convergence Appliance was selected for an InfoWorld Technology of the Year award. See the slideshow of all winners in the networking category. ]

What the company brought was the latest iteration of its MCA (Mobile Convergence Appliance). Installed at the customer site, the box takes on the difficult task of handing off active mobile voice sessions between disparate wireless networks.

Here’s the example that attracted us to DiVitas in the first place: We're carrying on a conversation on our Cingular 8525 and Verizon XV6700 handsets, ruminating on the ruinous pricing imposed on us by the cell phone industry, when we suddenly roam into range of our office WLAN, happily equipped with wireless VoIP. Our Cingular handheld money pit seamlessly switches over to our internal VoIP network without dropping our ongoing conversation. (You can run the MCA without a VoIP PBX, as DiVitas has that functionality built-in as a backup.)

The MCA can't handle this task on its own, however. Helping out is the MCC (Mobile Convergence Client), a device-independent software client that sits on the mobile device and communicates back to the MCA.

Essentially, the MCC and MCA put their electronic heads together and analyze the voice quality on the existing link, as well as on surrounding links, including compatible cell carrier networks, Wi-Fi networks, and Bluetooth networks — as long as you configure your mobile devices to scan for these. If the call quality is robust enough in both directions, the system will switch the call.

To do this, the MCC contains a multimode communication interface that knows the specific requirements of voice traffic and will soon apply those same smarts to a wide variety of network-dependent apps, such as e-mail, employee presence, SMS (short message service), instant messaging, and more.

During our test, the MCC was specific to WinCE clients. But in the near future, DiVitas will support a wider variety of client platforms, including Symbian and Nokia E-Series handsets, with Palm support further out. Embedded Linux will wait until more handsets are available.

Configuring the MCA is fairly easy, considering its functionality. To set up our test box, all we had to do was provide a single IP address facing the outside world and another facing inward. The MCA already understands NAT traversal as it relates to SIP traffic, so as long as it can be seen from the outside world, the MCA can take care of everything else. Once that address was provided, we also had to log in to our firewall and open three ports: one for secure HTTP and two for the DiVitas software).

That's enough to provide basic connectivity for the MCA. However, you can tweak the MCA's configuration in a variety of ways, including your own parameters for voice quality and bridge information to your local PBX. The MCC software can be similarly tweaked, especially when it comes to security.