802.11r (FT) support on 3702i AP under 9800-CL WLC

[Jeff A.]

I've made an interesting observation recently.

When devices roam to a 2802i AP they make it there via 802.11r (FT: Fast Transition) no problems, however when they roam back to a 3702i AP they go via 802.11i (Slow).

I'm not too fussed as the speed difference is 5-10ms which is not much, but I am interested to figure out why this is the case.

The 9800-CL was running 16.12.4a and I've upgraded to 16.12.5 and getting the same results.

Is anyone else observing the same thing? Is there a bug I'm not aware of or some other incompatibility? Keen to hear your thoughts.

[patoberli]

It sounds like you found a bug or not supported feature. Please note, 17.3.x is the last supported release for the 3700 series (AC wave1 family), but I couldn't find any addition or missing features list. There were various 11r bugs fixed in 16.12.5 though, so I tend to say you found another bug. If you like it solved, open a TAC.

I don't have an 9800, so I can't test it.

[Jeff A.]

TAC will be the way to go for sure, but I am still curious if anyone else has experienced this in the wild.

Most admins I know have upgraded from 3700 to the 9100 series, in fact that is how I ended up with two of my 3700's...

[patoberli]

To be honest, most of the users probably don't even realize if 11r is sometimes not working. So I guess only people actually using wireshark while "being bored" will realize it

[Jeff A.]

You’re not wrong when using PSK, but when using 802.11X I will get constant complaints of calls dropping out while moving through the building when it’s not working. As a workaround I pushed a PSK profile on a different SSID and the devices are none the wiser, but would still like to have it fixed at some point.

More than likely I’ll just upgrade the AP’s at some point anyway.

[patoberli]

In that case, please open a TAC and keep us updated.

[Scott Fella]

I agree... most people only care as long as their experience is good.  Basically when they have to look at their wireless icon or disable/enable the wifi, thats when they complain.  It will be interesting what TAC will say.

[Jeff A. · Accepted solution]

Reading between the lines there seems to be an incompatibility between the 2802i and 3702i AP's and the 9800-CL, so the 'unofficial' solution is to replace the 3702i AP's with a newer models or downgrade to vWLC.

Alternative solution is to simply disable 802.11r as it's not yielding any real world improvements for my PSK environment. I'll take this route until I can get my hands on some newer AP's.