IP Telephony Moves Forward

And in the enterprise market, the convergence of voice, data and video traffic on a single IP-based network—often referred to generically as IP telephony, or IPT—is moving rapidly toward the mainstream.

“IP telephony has moved out of the early adopter phase and into the early majority phase. There are some major corporations that have deployed this technology,” says Matt Tighe, senior consultant and practice lead for convergence at International Network Services (INS,www.ins.com), a Santa Clara, Calif.-based network consulting firm.

According to a recent report from Insight Research Corp. (www.insight-corp.com), Boonton, N.J., shipments of VoIP phones for use with IPT private branch exchanges (PBXs) are expected to grow at a compound annual rate of more than 20 percent between 2004 and 2009. Shipments of traditional, analog time-division-multiplexed (TDM) phone technology, meanwhile, will decline at roughly the same rate during that period, the company projects.

For manufacturers converting to IP telephony, the benefits can be substantial. According to various reports, the total cost of ownership for a converged network can run 40 percent to 60 percent less than that of separate voice, data and video networks. The savings include reduced staff and administration costs, and lower cabling and infrastructure costs. Long distance calling charges are also reduced, because IP voice calls carried on corporate data circuits, or even the Internet, can avoid per-minute phone company tolls for voice traffic between corporate locations.

One oft-cited IPT savings comes through a reduction in so-called move/add/change costs. When an employee changes locations in a plant, for example, the cost for phone cabling and reconfiguration in a traditional TDM environment can run $50 to $150, says Tighe. But that cost drops to pennies with an IPT system, he contends. “All you do is unplug the phone from the data jack, plug it in at the employee’s new location, and the phone will automatically re-register itself and get back on the network with the same phone number it had before.”

These kinds of infrastructure savings alone, together with reductions in long distance tolls, can often be enough to make the business case for IPT, particularly for new plant or greenfield applications, says Russell Sellers, director of product development at NetSolve Inc. (www.netsolve.com), an Austin, Texas-based remote infrastructure management company that is being acquired by Cisco Systems Inc. (www.cisco.com), San Jose, Calif.

这是更不用说一系列额外的公关oductivity improvements and other competitive advantages that IPT can bring to a company, says Sellers. “In an IP telephony environment, you’re actually getting a new PBX that has new functionality and capabilities that allow you to do things that you couldn’t do historically with the traditional PBXs,” he says.

One example in a manufacturing environment might be an IP telephony handset on a factory floor that enables workers to order parts replenishment with the touch of a single button. “The phone keypad and the functions on the phone can be integrated with other backend business applications, so you don’t need both a phone and a computer at that location,” Sellers explains. Some early IPT handsets were not rugged enough for some hostile factory environments, he notes, but those problems now have been generally overcome.

Oops, dropped it

One good time to consider conversion to IPT is when leases expire on existing TDM PBX systems. But users must look before they leap. “Voice, unlike data, does not handle errors in the data network very well. They manifest themselves as dropped calls, gaps in the voice conversation and just generally low quality,” says Tighe, of INS. “If your data network is not highly tuned, your Voice-over-IP call is going to sound like a really bad cell phone connection,” he warns.

The INS consultant recommends that companies do a thorough analysis of their network systems before implementing an IPT system. “You’ve definitely got to have a switched network,” he says. “Using the old Ethernet hubs is just totally out of the question.” So-called “quality-of-service” features within the network equipment must almost always be turned on, Tighe adds.

An analysis of current voice calling patterns is also advisable. “A single voice call takes minimal bandwidth, but if you’re doing hundreds of calls, that becomes a little more significant. If your data network is already constrained, it could push you over the edge,” Tighe observes.

Wes Iversen,wiversen@automationworld.com