Martin County, 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.

Manage With Care

Upgrading the network was essential when the Arizona Cardinals NFL football organization 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 category 3 to category 6 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."