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 $5000, 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.

Have you 'Got the Power'?
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 Florida chose to deploy VoIP at sites that already had fibre-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 fibre-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 centres where employees may be on the phone as much as 85 percent of the time. Those environments typically demand extensive upgrades.

Manage With Care
Upgrading the network was essential when the Arizona Cardinals NFL football organisation deployed its VoIP system. The Cardinals' IT staff planned a new training facility and headquarters with VoIP in mind from the start. This ensured that its IP network would be capable of supporting voice, video, and multimedia. The first step was to upgrade its cabling from CAT3 to CAT6 to handle the demands of video, which is used increasingly by NFL coaches on their laptops, says Mark Feller, the team's technical director. "We upgraded because we were thinking ahead. VoIP demands less bandwidth than video. We put in cable that could handle video."

At Erlanger Health System, it was hard for the IT staff to believe that their tried-and-true switches and cabling would prove unworthy of voice. After close inspection, Haltom says, substantial changes were necessary. "We were hesitant at first to 'doubt' our network because we had just gone through a complete core/edge upgrade with all new [Nortel] Passport 8600 and BPS2000 edge switches," he recalls.

"In terms of deployment, we think of this as 'distributing' all the things you may take for granted in a larger computer room facility. Push larger UPS and HVAC units, as well as more and more switch ports out into the closets. Layer in the redundant infrastructure and fibre-optic paths to mission-critical areas, and you have effectively converted your campus, or campuses, into giant computer rooms."

To keep voice moving in Martin County, Kryzda says voice-packet prioritisation by means of service-based "tagging" is one way to ensure that voice data gets delivered to where it needs to go first. This method assigns priority to voice traffic and thereby allows it to move on the network at an acceptable rate. It differs from the other common technique, in which a portion of available network bandwidth is carved out for voice services.

With plenty of available bandwidth, Kryzda says the QoS technique did not have to be implemented. "We also had concerns about having to implement QoS to guarantee delivery of voice traffic, preventing echo and warble, but we seem to have enough bandwidth to have precluded implementing this feature."

Remember to monitor
Tagging voice packets allows Kryzda to assign packet-tagging priority to the VoIP traffic and monitor it using network monitoring tools for packet loss on each link.

"We upgraded network switches where necessary to support this service-based QoS. We proactively monitor all voice and data network connections using open source-based software monitoring tools, checking for performance and outage issues," Kryzda adds.

A big part of initial planning should be devoted to how to manage the increased load of voice data. Voice data comes with a raft of additional requirements, such as increased bandwidth and packet prioritisation, and several tactics must be employed to minimise voice disruptions.

"The biggest area of concern for IT managers is performance management," says Irwin Lazar, senior analyst at Burton Group. Managing a real-time application such as voice across a data network can be problematic, he notes, because IP networks were never designed for the strict latency and jitter requirements of voice. "Enterprises require not only a good QoS architecture, but the tools to manage voice performance in real-time, and to be able to both proactively and reactively troubleshoot problems as they occur."

Telecom vendors such as Alcatel, Avaya, Cisco Systems, Nortel Networks and others provide management tools along with their VoIP product offerings while network management software vendors, including Brix, NetIQ, Qovia and Telchemy, have licensing agreements with vendors or sell their products directly to end-users.

The software usually consists of a console that lets IT staff view how well voice traffic is moving across the network, and agent software, which gets embedded in equipment that sits in the VoIP calling path - gateways, routers, switches, vendor-supplied appliances, and more recently IP phones. The agent can report in real time on VoIP quality of service problems, such as packet loss, discard, latency, jitter and signalling issues. But VoIP management software alone is no substitute for expertise in telephony.

Where to measure voice
At what part of the network should you measure voice performance? There are several options: at switches, routers, and gateways, for example. The most crucial spot, however, is at the end point where problems are most noticeable to users.

"Nothing can substitute for the end-user experience," says Alan Clark, CEO of Telchemy, a provider of network management software to telecom vendors. "There are 12 different router interfaces between here and India, but only one end point."

Financial constraints are still an obstacle for many IT departments, according to Forrester Research, but users are finding ways to justify expenditures through significant ROI. (Hardware and solutions can range from $10,000 to $100,000.)

According to Erlanger's Haltom, "Our fit is a pure cost-avoidance model where we utilise new construction and renovation in all areas and campuses to rip out existing voice and data networks and consolidate it all into one single network, thus avoiding the expense of things like the second line, patch panel ports, other materials, and the best part - managing one network infrastructure instead of two."

Those who have gone the distance say the cost is worth it. Hank Lambert, director of product marketing for the voice technology group at Cisco, emphasises the importance of an initial network audit, saying that it will save the company money in the long run.

In addition, "you have to look at the vintage of all the Ethernet switches," Lambert says. "You should have Ethernet layer 2 and routing layer 3. You also do want to get the tools. Make sure they're good and in your budget from the beginning. That causes disappointment among executives when all of a sudden the cost of tools is added to the equation. You can pay up to $20,000 for Cisco's tools in a medium-sized company," Lambert says.

On the horizon
Costs aside, performance stands to improve even more in the year ahead. For one thing, vendors are expected this year to offer products that allow for QoS reporting calls based on SIP. Meanwhile, standards such as RTCP-XR (Real-time Transport Control Protocol Extended Reports), currently in the RFC stage with the IETF, will allow for better end-point monitoring, according to Telchemy's Clark.

"Performance management frameworks use these standards, and they need IP phone suppliers to support these," Clark says. "Test-equipment vendors use them. We gave the IETF key information they needed about protocols," Clark says.

Emerging standards will also help keep voice performance at a satisfactory level. Haltom says he looks forward to the IEEE's emerging PVQM standard, developed with Telchemy and based on RTCP-XR. "This is what we are truly waiting on to get fully implemented over the next couple of months in order to gain a pro-active handle on VoIP session-related issues such and echo, jitter, and other latency-type issues," he says.

Whether these maturing technologies will entice the holdouts to move to at least the pilot stage in 2006 is uncertain. Being sure about what you're getting into is the only way to craft a deployment strategy to carry your company forward.

"You're blending two network worlds that are fundamentally different," says Tim Gaines, vice president of field sales at Covad, a provider of integrated voice and data service. But, he adds, they can and do coexist peacefully.