What is Airtime Fairness


What is airtime fairness and why do I need it?

Customer Environment

Legacy and latest standards based clients operating in the same environment

Root Cause

Slowness of higher data rated client in the presence of slow clients


802.11 standards have evolved over time. Over a decade ago, 11 Mbps is the fastest speed you could get over WiFi. Current 802.11n standard and upcoming 802.11ac standard devices (802.11ac draft standard devices are already out) can give speeds in the range of 100s of Mbps.

In a typical conference room style environment someone could be using a old laptop with 802.11g standard while rest of the crowd is on latest 802.11n standard laptops OR tablets.

By the laws of Physics, slow devices take relatively longer times to transmit and receive data compared to faster and newer devices. This gives less time to faster devices and disproportionately longer times to slow transmitting devices. Similar behaviors in air time can be observed if a device is farther away from an access point relative to other clients.

From the above it is obvious that you might want to cut down time given to legacy and distant devices to allow faster devices download data for longer times. This can significantly increase overall capacity of the network. To achieve such objective Airtime Fairness is introduced.

Airtime Fairness gives equal amounts of air time (instead of equal number of frames) to each client regardless of its theoretical data rate. This will ensure higher download speed to latest devices when slower devices are connected to the same AP.

Just as an additional note, band steering in combination of Airtime Fairness will really help with the speeds since most of the latest clients are dual-band enabled.

Article Number:

March 05, 2014 12:07 AM (over 6 years ago)

Performance, ZoneDirector, ZoneFlex Indoor, ZoneFlex Outdoor


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