Corporate IS departments that spent heavily on data networks in the ’80s, laying down high-bandwidth IP pipes to bring email, Web, and database applications to every cube and cranny, may havegiven CFOs and financial types some long nights. But in the ’90s, the knock on the door by the CIO brings good news. There’s gold in that data stream: excess bandwidth can carry intraoffice voice, and that ultimately represents saved toll charges. Edge devices, like VoIP gateways, encapsulate digitized voice within IP packets, the ticket that’s accepted by routers, gateways, and hubs everywhere.

Difficult to manage

As these intranets have grown more complex, they’ve become more difficult for IT departments to manage. Virtual private networks, offered by data carriers and ISPs, start to look very appealing to this enterprise market. ISPs can deliver VPNs to enterprises on the cheap because their new, digital infrastructure — ATM and frame relay hardware — avoids the costlier leased lines sold by the old carriers. VPN providers also have the staff and resources to completely manage an intraoffice network. Many of the same arguments that apply to Centrex in the voice world make the case for VPNs in the digital world. Data carriers can keep up with new technology for you, and extra bandwidth can be allocated from their enormous reservoir at less cost than it would take for you to go out and buy it.

VPNS are hard to control


Unfortunately, most data VPN providers are not at the point where they can offer VoIP to their enterprise customers. Although your network admins may be able to carve out enough bandwidth on a company’s IP backbone, the VPNs generally do not have that same level of control. Their networks are often stitched together from others, and the ISPs often go to super networks, the ISP’s ISP (companies like ITXC), for the bandwidth they need. Data VPNs do not have “end-to-end” control of their networks and can only hope that all the intermediate routers traversed by the IP packets comply with common QoS (Quality of Service) standards. However, the waters are being tested, so take a look at PSINet’s PSIVoice and AT&T’s Global Clearinghouse in the roundup.


The task waiting for corporate network planners who wish to deliver on the promise of free voice is managing data and voice together on the same wire. Fortunately, the inventors of the Internet realized that different applications require different types of service: interactive activity demands quick turnaround, whereas bulk file transfers can take their time.