Optical/IP Networks

Throwing Brix at Glass Houses

Our friends at Light Reading recently highlighted a study from Brix Networks that cites declining IP phone call quality over the last 18 months. See VOIP Quality Getting Worse. It's a catchy headline, but the testing methodology seems to say more about broadband Internet network congestion than the quality of actual VOIP calls. To showcase its real-time VOIP and IPTV testing and monitoring products, Brix launched the TestYourVOIP.com site in March 2004. Since then, users have generated nearly a million simulated SIP-based VOIP calls. To do so, they download a Java applet that acts as a SIP calling client. The client makes a "call" through Brix's SIP network, which Brix monitors to meaure call quality. According to the Brix press release: "Nearly 20 percent of Internet telephone test calls experienced unacceptable call quality over the last 18 months." How so? Since launching its test Web site, Brix has clocked Mean Opinion Score (MOS) calculations for conversational voice quality and notes: "The number of test calls throughout this time that achieved a MOS of 3.6 or higher, also known as Acceptable Call Quality (ACQ), was only 81 percent." Not so bad actually, but here's the punch line: "Over the last few years, the global market for consumer VoIP services has grown to nearly 20 million subscribers. These results from TestYourVoIP.com indicate that during this same period, Internet call quality has declined," said Kaynam Hedayat, vice president, engineering, and chief technology officer at Brix. That's a bit of a leap, considering that Brix is not actually measuring the quality of calls delivered through VOIP service provider networks in this test. Might another equally valid conclusion from this exercise be that Brix has trouble designing and operating a reliable SIP-based VoIP network? Seriously, what the test results may actually point to is increased broadband and Internet network congestion and its impact on latency-senistive applications, like voice and video. And, how such applications suffer without the use of traffic prioritization schemes. Maybe Brix should change the name of its test Web site to demonstratingthedrawbacksofsocallednetworkneutrality.com Or better yet, areasontobuymanagedcablevoipservice.com -- Michael Harris, Chief Analyst, Cable Digital News
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