What is Dynamic Airtime Scheduling?

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  • Updated 4 years ago
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This is also referred to as airtime fairness, and ensures that “slow-speed” clients don’t monopolize the resources of an AP radio. An old rule-of-thumb used to state that when the first 802.11b client joined the network, the entire network performance dropped to 802.11b speeds. The reason was due to monopolization of airtime by slow-speed clients, starving “high-speed” clients of adequate access to transmit, resulting in severe degradation of throughput for those clients.

Dynamic airtime scheduling gives equal airtime, rather than frame transmission opportunity, to clients, thereby allowing high-speed clients to achieve much higher throughput without significantly impacting the slow-speed clients. This is true between 11n slow-speed (e.g. tablets, smartphones) and 11n high-speed (e.g. laptops) clients or devices capable of higher speeds but positioned farther away from the access point. And we can tie Airtime allocation into Client SLA minimum throughput levels that administrators can define per User Profile.
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FAQ poster, Official Rep

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Posted 5 years ago

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Jade Rampulla

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Why isn't this a default setting? It seems to make tons of sense to turn it on. Are there any reasons to leave it off?
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Crowdie, Champ

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Some people in the forums have reported issues with some Apple products when dynamic airtime scheduling is enabled.
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Mike Kouri, Official Rep

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Other than as Crowdie mentioned that some people have reported problems with certain products when it's enabled, no, I can't think of any real world reasons to leave it disabled.

So why is it off by default? Inertia, and benchmarks. When we implemented it we weren't sure it would be appropriate for all environments, and we didn't want to fare poorly on benchmarks tests back in those days that often were not really reflective of real-world environments.