PPSK and CPU usage

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Does PPSK use more CPU than other security methods? We seem to overwhelm our APs fairly easily and I'm wondering if it is PPSK because of the following. Most of our APs are AP120. We can usually have about 30 laptops running on them without PPSK just fine, but when we have a meeting with staff that are all using PPSK the AP starts to show 100% cpu usage.
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Ryan_w

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Posted 5 years ago

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Crowdie, Champ

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What version of HiveOS are you running on the AP120 access points?

Your issue may just be capacity. The AP120 is not the highest capacity access point so you may need a higher capacity access point; such as the AP320 or AP330; in the meeting room.
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Ryan_w

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Just upgraded them to HiveOS 6.0r2b.1190, was on r2a when I last had this issue. So there is no reason to believe that one security method compared to another might effect the CPU capacity? Is there any way to set max clients per AP so you don't overload it?
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Sam

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Ryan,

You can set the max clients per AP under the radio profile. Each radio profile defaults to 100 users. This setting can be modified under Client Selection.

You can also modify this by adjusting the maximum users per SSID under the Advanced Settings>Maximum Client Limit.

Both will net the same result, the radio profile allows you to be more granular.
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Ryan_w

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Sam,

Thanks, I will try that! Any tips on avoiding certain things that can cause the CPU usage to spike on the AP120s?

Ryan
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Sam

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Ryan,

The more roles/services[DHCP Server, RADIUS server, PPSK server etc] you put on the AP the higher the CPU usage will be. The more users connected and actively passing traffic will also increase CPU utilization.
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Ryan_w

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So, if I setup a RADIUS server running on separate hardware that might reduce the CPU usage some as compared to PPSK using local auth?
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Sam

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Ryan,

It may, but then you lose PPSK. Often we recommend placing services on APs that are not going to be under heavy load. Are you actually noticing any negative effects with the AP running at or near peak?

Bare in mind there is a delay from the time the polling interval grabs the data from the AP and the time that data is presented, it's already old. It may mean that at that point in time the CPU was at 100%, but not now. This changes constantly and happens more frequently than we would want to spend cycles updating the graph.
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Ryan_w

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We do. Sometimes complete drops of the WiFi connection and other times just slowness. I've seen the APs sit at 100% for a few polling intervals.