Issue with two new Dell PC's conntecting to a further AP with terrible signal

[keithsauer507]

We have a newer training room that was thrown together this year and we have an issue where two of the 4 pc's seem to find their way to an AP that is on the floor above them at 2.4 GHz.  The ping times are terrible, like over 1000, and they complain of connectivity issues.  I can't even remote control onto those machines.  What I have to do is log into our 5508 controller and reboot the AP above them and then these machines find their way to the AP that is on the ceiling just outside this room at 5 GHz.

The 5508 WLC is supposed to orchestrate all of our AP's and at this particular building all 4 of the APs are in the same AP group.  3 AP's on the second floor are the 3802i's and the 1 AP on the first floor which is a newly leased space is a 3502i.  We threw a spare AP there since the budget did not have any line items for this space.

What could be a possible fix?  Would replacing that 3502i in the first floor with a matching 3802i make a difference?  There is only 100mbps metro Ethernet between this building and the HQ facility so the speed was not really a concern.  However 1gbps fiber is being built to the site from another provider and we will run it with a lower cost OSPF and just use the 100mb circuit as a backup.  So in normal operations in the near future the site WILL have 1 gig to HQ and then maybe it would make sense to upgrade this access point.

Any other ideas are welcome.

[Scott Fella]

Well, devices prefer the "faster and better" ap.  You have 3802's on the 2nd floor, those are ac capable access points.  Then you have a 3502 which is only 802.11n.  The devices will prefer the 3802 and not the 3502 which you have already seen.  My suggestion is to either replace that ap, or create a new SSID just for that floor and add that ssid to a new ap group which only includes that ap.

Depending on how comfortable you are you can also disable the lower data rates on the 2.4ghz to prevent devices from connecting at a low rate, now this can affect your other floors, so that is why I asked how comfortable are you with making and or understanding what these changes can affect.

[keithsauer507]

Ok we have 14 3502i AP's throughout the org.  The 5508 End of hardware support is in 2023 (July I think?).  Anyway that gives us budget year 2022 and 2023 and maybe find a little bit in this year yet to replace all the 3502's.  Im thinking of going to the 9800 virtual controller in our ESXi farm, and from what I am seeing that controller does not support those older AP's anyway.  So I agree, I think the right move is to upgrade that AP, then that whole building will match.  Thats one less of the 14 older APs in inventory that we need to replace prior to the 5508 being replaced due to end of hardware support.

I'm going to try to suggest this to management and the good news is there's a reason to migrate anyway and our org never keeps hardware past the EOL support date (In fact we are replacing a lot of 3750X switches this year).

[patoberli]

What you could do, but this takes some planning, is to lower the signal strength. Depending on how dense your AP placement is, you could maybe lower the signal on them by 1-2 power levels. Floors typically have a very high dampening effect on the signal. The idea is to make the signal of the AC APs worse enough on the other floor, so that the clients decide to take the "slower" data rate, but much stronger signal. 

This will make your cells smaller though, so if you are already tight with the signal and the cell borders, this might not work for you.

Another thing is what Scott already mentioned, disable some of the lower data rate (disable 1 - 12 Mbps, maybe even 18). This has a similar effect and can also cause issues for the clients at the cell edge. 

[Leo Laohoo]

What is the wireless NIC model and what firmware are they running on?