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Wi-Fi voice ecosystem is still evolving

When evaluating Vo-Fi, consider the many piece-parts
Wireless Alert By Joanie Wexler , Network World , 04/09/2007
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One of my recent newsletters pointed out the dearth of power-save-certified Wi-Fi devices in general and Wi-Fi phones in particular.

Based on reader feedback, let me clarify that power save, which lets a handset doze when not in use to conserve battery power, is just one QoS component needed to optimize voice-over-Wi-Fi, or Vo-Fi, experiences. My point, though, is that there seems to be an awful lot of industry hype about Vo-Fi, considering the neophyte state of certified technologies required to deliver it reliably on a large scale.

Lack of enterprise-class devices—particularly handsets—that have been Wi-Fi Alliance-certified for power save and other QoS capabilities makes you wonder just how well large-scale Vo-Fi deployments would actually work in the standards-based world as it currently stands.

Here’s the status: the Wi-Fi Alliance has certified voice-capable handsets for basic Wi-Fi and security interoperability, but it doesn’t begin actual voice certification testing for enterprises until the first half of 2008. Enterprise voice certification will require interoperability of the currently optional Wi-Fi Multimedia (WMM) Prioritization, WMM-Power Save and WMM-Admission Control components of the 802.11e QoS standard.

Also, elements of the emerging 802.11k standard for radio resource management and 802.11r for fast roaming will be required for the enterprise tests, according to Gerri Mitchell-Brown, who chairs the alliance’s Voice over Wi-Fi Marketing Task Group and is Wi-Fi strategist at Polycom/SpectraLink. These standards haven’t even been completed yet.

With all this work still to be done, how is it that Vo-Fi has seen the limited success that it has?

First, business Wi-Fi networks aren’t very heavily loaded with data, and contention hasn’t been much of an issue in many organizations. Putting all voice in a virtual LAN and then prioritizing that VLAN has done the trick in such organizations—for now.

Second, veteran wireless voice system provider SpectraLink, recently acquired by Polycom, has long had proprietary prioritization and call admission controls in its system, which have served the voice-centric Wi-Fi population quite nicely.

Finally, let me clear up an omission. The former Symbol Technologies’ “thick” access points, now the Motorola AP-5131 and AP-5181 since Motorola’s acquisition of Symbol in January, have indeed been Wi-Fi certified for WMM-Power Save. I overlooked these devices when discussing the slim pickings of power save-certified, enterprise-class devices because of the name change and regret the error.

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Only been averaging 70%By Anonymous on January 13, 2008, 9:36 pmOnly been averaging 70% success rate with Vocera after numerous and expensive tune-ups. They keep telling us to eliminate other noise and it will work better. ...

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Campus-wide Vocera voice over wirelessBy Anonymous on April 10, 2007, 10:45 pmI couldn't agree more. I've deployed Vocera on a campus-wide basis in a local hospital in my community. I'd give it about an 85% success rate...better than expected. Re:...

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