According to a survey by Harris Interactive, 12 percent of businesses have already deployed it, and another 29 percent are planning to do so before the end of the year. Harris also found that 87 percent of business decision makers were aware of VoIP.
Not surprisingly, companies like Ford, Bank of America, New York Life, Merrill Lynch and the Erlanger Health System have announced their own VoIP implementations.
Erlanger, for example, has multiple campuses in the vicinity of Chattanooga, Tenn. Its separate voice and data networks covered a 125-mile radius and 30 sites. On the voice side, it ran a no-longer-supported ATM Local Area Network (LAN) and Lucent PBXs (phone switches) that were no longer under warranty or maintenance contracts.
The organization operates one centralized data center with 163 Windows servers for general departmental applications, a couple Linux servers for DNS and about 19 AIX UNIX servers for financial and HR applications. The data center now also is the home of several dedicated servers, which function as an IP-based PBX -- Nortel Networks' Succession 1000 server and Nortel's Multimedia Communication Server (MCS) 5100.
These boxes have Nortel software loaded onto Dell servers. They utilize a data backbone based on Nortel switches -- primarily the Passport 8600 and Passport 8300 routing switches, as well as the Business Policy Switch (BPS) 2000 and BayStack 460-POE -- and a Synchronous Optical Network (SONET) smart ring provided by BellSouth. Nortel OC-3 links connect Erlanger's downtown campus with three remote campuses. Voice and data run across the same Ethernet path, although all voice-based packets are shuffled to a separate switch.
''We have several servers in our computer room that run voice application software and act as proxies for telephone calls,'' says Haltom. ''The good news is that users have not been able to detect any audible difference between the old and new phone systems.''
Rather than a campus-wide deployment, Erlanger elected to gradually add VoIP. Beginning in 2000, IT organized a VoIP upgrade around a campus renovation and building program. Out of 8,000 phones, 1,300 currently run on IP. As the old PBX still runs well, Haltom saw no reason to dump it. In fact, he intends to keep it running for another couple of years until VoIP has been rolled out to every phone.
In terms of VoIP costs, the hospital has spent more than a million dollars to date. Haltom expects the job to exceed $2.3 million by completion.
''The biggest stumbling block is licensing,'' he says. ''Every IP device that talks to a switch has to have a license.''
However, the savings are significant. Haltom cites a figure of $40 saved per VoIP phone due to eliminating the need for separate data and IP lines. In addition, the technology brings substantial cost savings over traditional long distance telephone calls.
While the cost savings may be impressive, viewing VoIP purely in terms of the present-day economics may be a mistake.
Doing it that way would mean anyone with an existing investment in a traditional PBX would have no reason at all to consider VoIP. The savings often aren't there when you try to replace an old system with an IP PBX.
''The replacement case is a difficult one to make,'' says Bern Elliot, a telecommunications analyst with Gartner Inc. ''It is probably smarter to present a vision case -- implement VoIP now and have faith that the applications will be there in the future.''
Elliot points out that shared voice and data opens up a whole new world of converged applications, many of which have yet to be conceived.
IP, for instance, can facilitate more sophisticated internal communications which improve collaboration and productivity. Voicemail, e-mail and faxes can be moved into a common inbox where they can be deleted, answered, forwarded or saved from one screen. VoIP also can provide 'presence management' -- the ability to see who else is logged onto the network at the time.
Helpdesk staff, for example, can see at a glance who else is available if a call needs to be escalated, then they can transfer the caller along with all supporting data or documents. This slashes the number of returned calls, and improves customer service.
Teleconferencing, too, can become a standard desktop and telephone feature, rather than something that needs to be specially scheduled. Simply clicking on an icon brings additional participants into the discussion.
''The big breakthroughs in VoIP are in convergence, not new applications,'' says Elliot. ''When you take voice off its own channel, it enables better applications for the enterprise.''
At Erlanger, converged applications are being rolled out.
At a basic level, users tailor communications to their needs. When calls arrive, for instance, they can have multiple devices ring simultaneously or one at a time in a specific sequence. A dynamic presence capability lets users in 40-person work groups visually check the availability of others before calling or sending an instant message.
Further converged features available from the Nortel MCS 5100 server include:
The healthcare organization's roving nurse force, for example, harnesses 120 mobile computers in conjunction with the Nortel phone system.
''This facilitates communication between nurses and physicians using presence indicators, instant messaging and other tools,'' says Halton. ''The whole phone tag scenario goes away, and time wasted is minimized.''
He also notes improved management capabilities.
''Older phones have little or no intelligence,'' says Haltom. ''Using SNMP, I can monitor VoIP phones and everything else under one seamless management umbrella. As issues are reported long before users notice it, our SLA's are overwhelmingly better.''
But running two systems simultaneously -- one VoIP and one traditional PBX -- can have its drawbacks.
Halton says whenever a new unit is under renovation, users complain they can only transfer voice mails to other IP phones, not to the rest of the campus phone system.
He expresses regret, too, about his attitude to VoIP during its earliest stages. Back in 2000 when the technology first appeared at Erlanger, a massive emergency room renovation project was underway. Due to lack of experience with VoIP, he elected to not put VoIP in there.
''It was more comfortable for me not to do it back then, whereas today it would have been easy,'' says Halton. ''We won't get back there till 2008, so I wished I'd done it.''