San Mateo, Calif. — A major end-user study of VoIP call quality by research firm Keynote Systems reported that despite impressive subscriber gains, the nascent telephony service has significant room for improvement when compared to its established land-line competition.
From May 21 to June 25, Keynote tested Vonage, AT&T CallVantage, Packet8, Primus Lingo, Verizon’s Voicewing and the free peer-to-peer calling service Skype. Calls were placed over both enterprise-level networks and residential DSL and cable broadband networks in the New York and San Francisco metro area.
Vonage ranked first overall as the most reliable VoIP service provider while AT&T CallVantage was tops in audio clarity. Keynote reported “noticeable gaps” between the two top providers and their competition, though Vonage and AT&T had “plenty of room for improvement.”
“VoIP reliability and audio clarity are important factors limiting the widespread adoption of VoIP in consumer markets. Consumers are unsure whether VoIP can live up to the dial-tone reliability and crystal-clear communication quality they have come to expect with traditional phone service over the years.” said Dharmesh Thakker, service level solutions senior product manager, Keynote. “While several providers and networks did well in certain areas, no single provider or network dominated the study in all metrics considered.”
The report concluded that “Internet telephone service is not yet up to the standards to which users are accustomed when using standard ‘plain old telephone service,’ and VoIP providers have some work to do to capitalize effectively on the growing consumer adoption of VoIP service.”
Not all of the quality issues can be pinned directly on the VoIP provider themselves, the study added, noting that the underlying Internet network that carries the calls also plays a role in call quality.
The services were ranked by reliability, outage hours, average number of call attempts, dropped calls, audio delay, listening quality and other factors that were merged into two general quality indicators: reliability and audio clarity.