VoIP quality

04 Aug 2006

How good is your VoIP service‾

A US service assurance firm promises to help you answer that question online at http://www.testyourvoip.com/.

Its test appliances in half a dozen cities worldwide check the latency, jitter and packet loss of each call to measure call setup, delivery and quality.

Even more clever, Brix Networks issued a press release of the accumulated test data over the last 18 months, indicating that a fifth of all VoIP calls suffer from "unacceptable" quality.

The result is a hit: the hitherto anonymous Brix has become known all over the blogosphere.

Brix says call quality has been steadily going down in the past 18 months, with consistently 20% of calls today below the 3.6 MOS (mean opinion score) service level.

That's a fairly rough test, though, and doesn't include any destinations in Asia, with the world's biggest broadband population which, arguably might skew the results higher. My own connection performed quite well. Out of a possible 5, it scored 3.8 for the link to Sydney, 4.1 to Vienna and 4.2 to San Jose and Helsinki.

Yet empirically, a lot of us would believe Brix. Even if you're using a cheap residential IDD service using IP in the trunk segment you've had plenty of long-distance where the other party is unintelligible.

It does underline the fact that VoIP as an application suffers from variable QoS because there isn't the same quality control as the established TDM environment. Or, as a spokesperson for broadband VoIP provider HKBN pointed out, voice quality is really a function of the quality of the broadband connection.

HKBN is a facilities-based VoIP provider. By contrast Vonage, for example, does not own its own infrastructure. These are not happy times for Vonage: after a disastrous IPO and a likely shareholder class action, its quarterly revenue has come in short of forecast, it's churn is going up and it has trimmed its next quarterly guidance.

There's surely a connection between Vonage's reliance on other companies' infrastructure and its declining position in the market, especially as it is competing with big players with their own networks.

Which brings us in a roundabout way to the industry's hot topic du jour, the "net neutrality" debate (which would be better termed the traffic tiering debate), sparked by AT&T's declaration that it wishes to tier the charging for discrete Internet services.

Brix CTO Kaynam Hedayat, presumably a neutral on "neutrality", says VoIP quality is declining because voice is losing the battle for network resources against services such as video and music downloads.

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