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Networking

Short-circuiting the VoIP revolution

Brix Networks CTO Kaynam Hedayat warns that VoIP quality is getting worse, not better.

    I love VoIP phone services. Unlimited long distance at half the price of landline phones but with four times the features. What's not to love?

    A new generation of voice over Internet Protocol (VoIP) phones, routers and other equipment are nearly idiot-proof to install and use by both consumers and businesses.

    But a funny thing is happening on the way to the VoIP revolution: Voice quality is getting worse, not better.

    Conventional wisdom would hold that the Internet should be getting better at handling voice. But since March 2004, we?ve been testing nearly 1 million Internet phone calls by all sorts of customers from around the world. The results are disheartening, showing a consistent decrease in voice quality based on a commonly used Mean Opinion Score. The bottom line: The voice quality of one in five VoIP calls is unacceptable according to the data. If the trend continues, unacceptable calls will increase by 5 percent each year.

    Simply throwing bandwidth at the problem will not suffice.

    I?m not advocating we abandon VoIP services. The fact that 81 percent of Internet calls are good makes me believe the quality gap is not insurmountable. Providers just need to fix the problems.

    The key causes of poor voice quality are late, lost or discarded packets and latency. But that's like saying cars are moving slowly because the highway is congested. There is no single cause and no single fix to the problem. It could be that your Internet service provider is throttling bandwidth from another provider. Or traffic has been slowed by firewalls or address translators. Or perhaps your call is conflicting with that huge video your neighbor is downloading.

    But it's not your problem to figure out. And simply throwing bandwidth at the problem will not suffice. Instead, providers need to apply technologies that lessen delays and the number of packets discarded by the network. Consumers and businesses that are thinking of moving to VoIP need to demand service level agreements that carefully measure the factors that hamper VoIP. Customers should look to both their VoIP provider and their ISP when having voice quality problems. There is an equal chance that the problem is in the network they use to access the Internet, the VoIP providers' infrastructure or the Internet itself.

    With VoIP quality falling, the industry cannot be complacent. Early adopters of VoIP technology may have been willing to accept an occasional poor-quality call, but the mass market of consumers and businesses won't. Service quality matters. And providers that hope to capture more of their customers' dollars need to consistently provide a high-quality experience.