VoIP call-monitoring a work in progress

A new generation of products that monitor voice-call quality on IP networks signals the maturity of enterprise VoIP technology. But monitoring voice quality is hardly an exact science.

A new generation of products designed to help businesses monitor voice-call quality on their IP networks is emerging, signaling the maturity of enterprise VoIP technology. However, monitoring voice quality is not an exact science.

Concord Communications Inc. recently announced the availability of its eHealth Suite 5.6.5, which includes new features that monitor the quality of calls over IP networks. A few weeks ago, Edgewater Networks Inc. added voice quality assessment to its EdgeMarc series of VoIP appliances.

These companies join a number of other vendors that have begun offering businesses the ability to monitor IP networks not only for latency, jitter and packet loss -- issues that affect voice traffic -- but also for the quality of voice service delivered through the handset.

"We are beginning to see a huge uptick in demand for voice quality monitoring from our customer base," said Frank Kettenstock, vice president of marketing at Marlboro, Mass.-based Concord.

Until now, it's been common for enterprises to test VoIP systems in their labs and deploy pilot programs, but not roll out the technology to the whole company. Now that that is changing, he said, companies understand that they need better network management and, in particular, a better way to assess voice quality.

Tracking the quality of IP-based voice traffic isn't easy, said Ray Keneipp, a vice president with the Midvale, Utah-based research firm Burton Group. Voice quality is measured on a one-through-five scale called the Mean Opinion Score (MOS). Five is excellent; one is terrible. Most switched network calls rate somewhere around a four, but Keneipp said the system is somewhat subjective.

Psytechnics Ltd., which provided the algorithms that determine MOS in Edgewater's product, used a vast linguistics database to help it determine the MOS scores. Iain Wood, director of marketing at Psytechnics, said the company used a database of 200,000 people, speaking languages from around the world, to help it develop algorithms that would accurately assess an end user's experience. While the score is still based on opinion, Wood calls it science.

But George Hamilton, an analyst with the Boston-based Yankee Group research firm, points out that there are plenty of problems with such a subjective system. For example, he said, if a call has quality issues at the beginning rather than at the end, it will generally receive a better score, even if the degradation was exactly the same. Small bits of degradation throughout a call will generate a worse score than short periods of intense degradation.

Different algorithms also account for those variables differently. In the end, it is a subjective experience that is being measured, not something as objective as application response speed, he said.

Nonetheless, some measure of voice quality is necessary for these large deployments, and MOS scoring is the best tool available, Hamilton said. "Latency, jitter and packet loss have not been a mystery," he said. "The gap has always been call quality. Now we are able to get a user perspective on latency and packet loss."

As these new products emerge, Keneipp recommends that businesses look for a number of features:

-- Products should monitor the call from phone to phone, and provide a window into the route that the call took, helping administrators identify trouble spots.

-- Products should allow companies to dig into the components of the MOS score, so they can see what amount of jitter or packet loss there was.

-- Products should allow companies to manipulate the algorithm to change the parameters if the user is finding that, for example, his calls can tolerate more jitter without a problem occurring.

-- They should allow users to correlate data from groups of phones on the same network so administrators can make comparisons.

The IP telephony call-monitoring issue also poses new questions to IT departments, Keneipp said. How often should phones be monitored? Should IT departments archive all of the monitoring data for every phone? Should companies monitor only new systems intensively, and then stop once they are running well?

Right now, there are no hard-and-fast answers. As systems are rolled out, IT departments should experiment with the approach that works best for them, Keneipp said. These systems are new, he said, and will take time to master.

FOR MORE INFORMATION:

Learn why an analyst says that, in converged networks, quality of service is paramount.

Get help from VoIP expert Carrie Higbie.

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