AT&T Can Extend PBX to Remote Sites

FLORHAM PARK, N.J. (06/30/2000) - AT&T Labs is developing a VPN technology that can extend corporate PBX functions to remote workers connected via VPN data links.

Although AT&T Corp. has yet to offer what AT&T Labs calls the Virtual Communication Service (VCS), at least one customer is said to be trialing it.

Unlike voice-over-IP vendors' "follow-me" technologies that extend corporate voice and data services by integrating traffic on an IP link, VCS uses the VPN connection to communicate with the PBX while voice signals stay on the public switched network.

Key to this capability is a small device AT&T Labs code named Yorkie, a box about the size of two decks of playing cards. Yorkie runs Linux software for IP Security tunneling, Dynamic Host Configuration Protocol for accepting ISP-issued IP addresses, a Domain Name System server and an HTTP Web server so it can interact with the computer.

AT&T has also trialed a software-only version of Yorkie and may ultimately release the service using that, but the processing demands of encryption may force the company to stick with hardware.

Norm Schryer, division manager of broadband services research at AT&T Labs, says Yorkie functionality could ultimately be squeezed into a PC card.

A VPN Internet connection to a corporate network is established using whatever is available - cable modem, DSL, wireless, ISDN or even a dial-up modem.

Besides supporting typical VPN data needs, that same link will connect a Java-based soft phone on a user's PC to the user's corporate PBX.

Once connected, users let the PBX know where they are by typing in their local phone number. Calls to the user's desk extension will be forwarded to the remote location.

To place calls or use other PBX features, the remote user clicks on a screen depiction of a telephone keypad on his PC. The PBX performs the requested function and rings the user's phone over a normal public phone link.

So, for example, if the user dialed extension 333 on the soft phone, the PBX would call the user's phone and then connect it to extension 333. If the user wanted to conference in more parties, he would instruct the PBX to do so using the soft phone display.

While a DSL or cable modem Internet link would give a fast link to the VPN, the service will also work via a regular dial-up Internet connection or wireless, according to Schryer.

AT&T says it may launch VCS this year, but pricing has not been set.

Such a service may be unique, says Lisa Pierce, an analyst with Giga Information Group, a consultancy in Cambridge, Massachusetts. Using a two-channel ISDN line to get simultaneous Internet VPN access and phone service would be similar but lacks the PBX extension features, she says.

MCK Communications makes equipment that performs similar functions. Its gear extends PBX functions over data networks, but requires customers to buy equipment for both remote and central sites and uses leased data links. It also requires a digital phone set. VCS works with regular phones and puts all the pieces together for the customer.

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