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Will AirFlow shift bode well for VoIP?

Apr 21, 20042 mins
Cellular NetworksNetwork SecurityVoIP

* WLAN shakeout begins with new AirFlow strategy

Start-up AirFlow Networks has changed its business model and now intends to license its “switch on a chip” technology, announced in January, to systems makers.

Systems companies can use the AirFlow technology to turn any Ethernet switch into a WLAN switch. AirFlow will also license its technology, royalty-free, to 802.11 chipmakers.

In a crowded market, AirFlow decided it would fare better licensing its technology than doing combat in a features war with other systems vendors. This move, if successful, could bode well for VoIP over WLANs.

AirFlow’s architecture is VoIP-centric, splitting the 802.11 media access control (MAC) component between AP and switch. The technology places the “collision avoidance” function in the AP and the “high-level MAC” – the part that handles client-to-AP association – in the switch. AirFlow says this enables blanket, single-channel coverage throughout a building, rather than requiring enterprises to build a “honeycomb” of cells using channels 1, 6 and 11 in an 802.11b or g network, for example. This avoids co-channel interference and AP handoffs (and the latency associated with them).

The company’s first licensee is Engim, which makes 802.11 AP chips that support simultaneous coverage for multiple non-overlapping channels. Since AirFlow technology allows a single channel to be supported consistently throughout a building, combining AirFlow and Engim capabilities could allow multiple channels to not interfere and avoid handoffs, says Brian Jenkins, AirFlow’s vice president of marketing.

The idea is that network administrators could opt to segment voice and data onto different channels to eliminate contention, enhancing performance and capacity.

Wireless switches with AirFlow switch-on-a-chip technology will communicate with APs using AirFlow-enhanced chips (such as Engim’s) via the emerging Control and Provisioning of Wireless Access Points (CAPWAP) protocol, says Jenkins. AirFlow hasn’t announced any switch-maker licensees yet.

The new IEEE standards committee, 802.11r, is working to maintain security while supporting fast roaming. AirFlow President and CEO Bob Machlin said in a statement: “Since AirFlow’s solution inherently provides secure fast roaming, we made a strategic decision to partner with WLAN chip and system vendors – instead of fighting against them – to facilitate the growth of VoWLAN.”