Lessons from real-world VOIP

Will 2006 be the year that voice and data convergence really takes off? Looking back, VOIP was one of the hottest and most hyped technologies of 2005. Yet despite all the attention, only about a third of IT departments have rolled out full-fledged deployments, according to a recent survey by Forrester Research.

Much of the reluctance can be attributed to the burden that VOIP can place on even the most efficient networks, in addition to concerns about voice quality, scalability, and QoS. Still, many experts say present-day technologies have smoothed over most of the potholes. Nonetheless, there is extensive provisioning involved in implementing and maintaining a VOIP system. Fortunately, the right deployment strategy can dispel any apprehension.

"People were told that VOIP is going to be the greatest thing," says William Stofega, VOIP research director at IDC. "But in some cases, people didn't do the necessary network planning. Ninety-nine percent of all VOIP network implementations that fail do so because IT departments didn't do their homework."

So, what do you need to make it work? How will you manage it? And how much will it cost? The answers vary and depend on numerous factors. Practically no one is ripping and replacing but rather installing hybrids that put VOIP where it yields the greatest benefit while leaving legacy systems in place elsewhere. Regardless of the scenario, early adopters are providing clear answers.

Proceed With Caution

Good planning begins with a comprehensive review of your existing infrastructure. For fees starting around US$5,000, telecom equipment vendors will help you decide which systems can take on voice traffic and perform adequately, and which ones need to be replaced. A rigorous pre-assessment also aids in identifying potential network bottlenecks.

When Erlanger Health System chose Nortel Networks to provide its IP telephony hardware and software, Nortel's first performed a full network audit. The inspection revealed how little the IT staff understood about impending network requirements, says John Haltom, network director at Erlanger.

The audit "was shocking proof of how much we needed to get a better understanding of our network prior to going large-scale with VOIP," Haltom says. For example, networking gear that could handle data traffic with only minor delays would not be capable of handling the stress of voice data, he adds. "We had duplex mismatches, NIC cards chattering in several locations -- all of which have some minor effects on data-based traffic," but with voice they would be a menace.

Of course, audits are a prelude for vendors to sell products, and they "aren't always looking out for your best interest," cautions IDC's Stofega. With that in mind, internal expertise, in addition to conferring with consultants and outside colleagues, become invaluable.

Ensuring that users get the voice services they need also hinges on cabling, according to Joanne Korsuth, CIO at Olin College of Engineering. Cabling will determine the viability of future services. With an eye toward expansion, you'll want to consider stackable switches with 24 or 48 ports each.

Power is also a consideration, Korsuth says, "so we have UPSes [uninterruptible power supplies]. That seems like common sense, but with VOIP, wireless, and power over Ethernet, it's as important a consideration as cooling in closets."

Martin County in the U.S. state of Florida, chose to deploy VOIP at sites that already had fiber optic cable in place, says Kevin Kryzda, the county's CIO. "We had to consider the network connection and bandwidth. We chose sites for VOIP that have fiber-optic cable broadband connection with a limited number of data network connections, thus considerable available bandwidth," he says. The network equipment changes began in 2001, when legacy voice services were either replaced or left as separate BellSouth circuits such as fax lines. Voice session quality was the yardstick; so far so good, he says.

Knowing your phone users' calling habits plays a key role in assuring clear, uninterrupted conversations over IP. "How long are people on the phone? How much voice mail do they want?" Korsuth asks. "Because voice is another IP packet, if students flood the network with MP3s or peer-to-peer connections, you have to rate-limit traffic."

Analysts estimate that for typical VOIP rollouts, it's safe to assume that users are on the phone about 20 percent of the time. That percentage rises dramatically, however, at large call centers where employees may be on the phone as much as 85 percent of the time. Those environments typically demand extensive upgrades.

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