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Alliance to pass WME, go directly to 802.11e

Nov 24, 20032 mins
Cellular NetworksNetwork SecurityWi-Fi

* IEEE, vendors examine voice-over-WLAN issues

The Wi-Fi Alliance says it will skip an “interim” certification for Wireless Multimedia Extensions, a component of the forthcoming IEEE 802.11e wireless LAN standard for quality-of-service.

Frank Hanzlik, the alliance’s managing director, explained that reports from the IEEE Task Group E’s meeting earlier this month indicate that the group is on track to ratify the full 802.11e standard by June 2004. At that time, he says, “The alliance will begin offering a certification for 802.11e and all of its components.”

WME is the 802.11e QoS piece that supports priority tagging and queuing. It supports eight priority classes per station and leverages Enhanced Distribution Coordination Function (EDCF), which requires mobile stations with lower-priority traffic to wait longer than those with high-priority traffic before trying to access the wireless medium.

Hanzlik says that WME is a subset of 802.11e’s “polled access,” which recently gained the new moniker Wi-Fi Scheduled Multimedia, or WSM. Polled access schedules time to devices based on needs or required bandwidth.

It seems that there are a number of industry issues that need resolving for voice over IP (VoIP) over WLAN support to become robust.

Several experts at the recent Next-Generation Networks show in Boston, for example, said compression algorithms such as G.729 should be added to the wireless mix.  Richard Watson, director of telephony product marketing at WLAN maker Symbol Technologies, said, “Most of the VoIP packet is the header. Compression is needed to increase packet-per-second throughput” and reduce latency.

Ben Guderian, director of marketing at wireless phone-maker SpectraLink, added that for predictable latency, battery life management of mobile devices, including “sleep modes,” are a consideration, along with bandwidth management to minimize contention and maximize available capacity.

And separately, Ron Seide, WLAN product line manager at Cisco, noted that fast, secure roaming at Layer 3 – across IP subnets – “will be important for voice for companies that want a segmented network.”

He said Cisco, which recently began shipping radio-frequency management tools and Advanced Encryption Standard-ready 802.11g access points, will support Layer 3 roaming sometime in 2004.

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