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> Broadband Gear Report's VoIP Alert for August 10, 2006

Up Front

VoIP Rollout Numbers Are High, But How's the Quality?

Cable engineers don't need more stats to know that MSOs are rolling out IP telephony services at a demanding clip. The technical community is the one staying up nights to make it happen. Quantity may be making upper management relatively happy (for now), but HFC engineers worth their VoIP salt aren't just thinking about expanding sub numbers. They're thinking hard about quality.

And while it's not all bad, some of the current news about VoIP call quality is not exactly pristine. For example, one out of five VoIP calls were deemed unacceptable during the last 18 months, according to recent data released by Brix Networks'. The info comes from the company's TestYourVoIP.com Voice Quality Testing Portal, which offers consumers a way to independently measure the quality of their cable- or DSL-based Internet phone connections for free.

From late 2004 through mid-2006, the test results generated by TestYourVoIP.com showed a consistent decrease in overall voice quality as calculated via a mean opinion score (MOS). Test calls with a MOS of 3.6 or better are typically regarded as having acceptable call quality (ACQ). The number of test calls in that time that achieved ACQ was 81%. (See the accompanying figure.)

Do We Really Need to Bat 3.6?

So, around 20% of VoIP calls maybe aren't hitting an MOS of 3.6. However, there's the idea floating out there in the technical community that always shooting for 3.6 or better is sometimes aiming too high. That's because if you've heard a 3.0-rated call, you might not think it was so bad. But that's completely the wrong way to look at it, according to Michel Nadeau, president/CEO of Minacom.

"The human ear can sense it is OK because the human brain is attached to it, and decodes extremely well," Nadeau tells Broadband Gear Report. "But think about interactive voice response (IVR) and direct banking applications, and their needs for voice recognition and speech security algorithms. What if the call has dual encoding on top of it like when you're calling a mobile number or through an interconnect using VoIP compression?"

Test units can hear the glitches that make voice recognition not work well, whereas a technician listening cannot hear these subtleties, Nadeau concludes.

Divide and Conquer, From a Central Locale

Roger Lingle, VP of the service assurance solutions business unit of JDSU's Communications Test and Measurement (T&M) group, agrees that VoIP is much more sensitive to network conditions, and voice quality is affected greatly by packet loss, jitter and delay.

"To complicate matters, these degradation factors, from an end-to-end network perspective, can be introduced at any point as the voice travels through many different network elements and different transport mechanisms," Lingle says. "Those include the MTA at the subscriber home to the DOCSIS channel over the electrical and optical HFC access network, to the CMTS router and potentially to a PSTN media gateway, announcement/voicemail server or the end subscriber.

Lingle explains that this sensitivity places greater demands on the customer service and engineering organizations to manage voice service quality and workflow between disparate groups (both corporate and regional) spanning the HFC plant, CMTS hub-site, IP network and voice PSTN gateways.

The potential result is a big bump in the number of truck rolls as compared to high-speed data and a lengthy meant-time-to-repair (MTTR) because of a lack of coordination for dispatches and information sharing between groups. "To avoid these service quality pains, it is essential for cable operators to have the ability to sectionalize the network from a centralized location," Lingle stresses. "That way they can detect voice service problems and effectively pinpoint issues to the HFC plant, IP network, PSTN hand-off or customer premise, as well as identify whether a systemic network issue is affecting multiple customers vs. a single customer."

Gear Watch

CableLabs Summer Conference and Beyond

This week at the CableLabs Summer Conference in Keystone, CO, Cedar Point Communications showcased new developments in SIP-based and IMS applications for cable telephony providers. The company demonstrated advanced SIP applications that increase subscriber dialing flexibility and also showed interoperation with core elements that support the anticipated migration to IMS platforms for fixed-mobile convergence.

Also at the CableLabs summer meeting, Nominum demonstrated an ENUM-based VoIP peering solution featuring Acme Packet, NeuStar and Siemens technology. This integrated solution incorporates Nominum Navitas, an ENUM-based IP-application Routing Directory, Siemens' SURPASS hiQ 8000 softswitch, Acme Packet's Net-Net Session Border Control and NeuStar's SIP-IX data services, including local number portability, which enable interoperability for VoIP peering architecture.

Sigma Systems provided a converged multimedia services product demonstration with Nortel at the CableLabs conference. They hosted a VoIP telephony product demonstration targeted to small and medium business enterprises. The demo showcased automating the rollout of Nortel's implementation of IMS and converged communications services.

• In other news, Time Warner Cable signed a two-year purchase agreement for the ARRIS C4 and C3 CMTS products. TWC has already deployed the 1RU-size ARRIS C3 CMTS in several of its systems and, in anticipation of this purchase agreement, placed its first C4 CMTS orders last week.
• The wireless industry association, 3G Americas, recently published a white paper that focuses specifically on IMS architecture, as defined by the 3rd Generation Partnership Project (3GPP). "IMS: Application Enabler and UMTS/HSPA Growth Catalyst," addresses the ways that 3GPP IMS architecture is best suited for the blending of real-time and non real-time multimedia services, and how it optimizes the application life-cycle through rapid and efficient service creation and deployment.
  
  It also shows how basic IMS services like presence, messaging and others, can become enablers of larger, personalized, interactive and collaborative multimedia services. The paper describes how IMS will play a key role in the introduction of these new services, and how the deployment of the GSM evolution through UMTS/HSPA will improve the user experience and generate demand for additional services. The paper was collaboratively developed by 3G Americas' board member companies, and is available for free at www.3gamericas.org.

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