Every SSID will perform 'beacon broadcast' 10 times a second. The more SSIDs you have, the more 'airtime' capacity is used for this overhead traffic, so the fewer capacity remains available for actual traffic.
Recommendation is to keep the number of SSIDs as low as possible, and if you go over 3-4 SSIDS, depending on the AP density, you are likely to start to notice performance degradation.
Here is the SSID overhead calculator by Revolution WiFi, that shows you that even with a single AP and 10 SSIDs, already 32% of your capacity is just gone for beacon overhead. If you have overlapping channels, APs that are using the same SSID, with 3 overlapping APs, all of your airtime is used for beacons, and no traffic can be passed.
Please reconsider the number of SSIDs, and even try to bring the number down. Maybe your Aruba partner can assist how to properly design this, with role based access you can probably easily bring down the number of SSIDs while still meeting your security requirements. If it is for 'branding', like shops having their own SSIDs, it's just a bad idea. This is just WiFi technology generic and not Aruba specific.
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Herman Robers
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If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check
https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.
In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.
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