Is voice over Wi-Fi out of gas?

* Alliance continues postponing Voice-Enterprise certifications

For years, the Wi-Fi Alliance has been poised to kick off its Voice-Enterprise certification program at any moment. Heck, I myself reported in 2008, when the alliance began its "Voice-Personal" certification testing of voice equipment for use in single access-point deployments, that "Voice-Enterprise certifications…are to follow in the middle of next year."

And yet, here we are two years later, and an Alliance spokesman has this to say: "The Voice-Enterprise certification program is expected to launch in early 2011. The program is currently in the final stages of development of the testing plan."

Major Wi-Fi changes ahead

The forthcoming Voice-Enterprise certifications are aimed at supporting voice call handoff and roaming among APs, while the existing certification, Voice-Personal, presumes a single AP and no handoff required. As you likely know, latency-sensitive real-time sessions such as voice require pretty robust levels of quality of service (QoS), which can falter when users roam among APs.

QoS is covered in Wi-Fi standards by 802.11e, which the alliance split into two "halves" for purposes of certification testing: Wireless Multimedia (WMM) for packet prioritization and a call admission control (CAC) function, necessary to prevent one too many voice calls from joining a network and knocking out all the other sessions in the process.

Did the Alliance do the industry a service or a disservice in splitting 802.11e testing into WMM and the CAC capabilities that are still to come? People in the industry have tended to use "WMM" and "802.11e" and "QoS" interchangeably, when WMM is really only part of the 802.11e QoS standard. As such, people may have believed WMM-certified equipment to be automatically voice-ready and wound up befuddled when it didn't work well.

Perhaps Vo-Fi can't really get off the ground in mainstream business until the Voice-Enterprise certification testing is well underway and users feel confident in the voice capabilities of the products. Then again, the delay in the certifications might mean that Vo-Fi misses a window in the enterprise, as users find workarounds for Vo-Fi, such as using mobile-to-mobile minutes on their cellular call plans.

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