1850 with ME: occasional traffic outages

[sasha]

Hi. We have a small WiFi network with two 1850i APs, 20 WiFi clients and a switch which provides PoE to the APs. The network is isolated from the rest of the world, there are no wired devices either. The amount of traffic is quite low.

But we're occasionally (e.g. 2-3 times per hour) experiencing traffic outages which last from a couple of seconds to 15-20 seconds. During such outage, the affected client can't send nor receive any traffic. Sometimes just one or two clients are affected, and sometimes all of them at the same time. We're detecting such outages by loss of keepalive messages that the clients exchange. Wireshark on the affected client shows it's trying to send messages but it doesn't receive anything during outage. Sometimes the affected client reconnects, and sometimes it doesn't loose the connection.

APs are running ME software 8.5.131. Client stats on the APs show just a small amount of Tx errors, show logg on both APs and ME doesn't show any obvious problem. ME GUI shows very small amount of interference and 0 rogue APs on 5 GHz. We tried lowering speeds and it seems to help to some extent (we're currently at 802.11n MCS13 2ss i.e. 240 Mbps), but outages still occur.

1) How to discover the cause of the outages?

2) Is there any way we could force a client to reconnect / roam if it doesn't receive anything in e.g. 2-3 seconds?

Thanks and best regards.

[Haydn Andrews]

Roaming is the clients decision so if the client has any ability to change this it would be on the client.

Has a site survey using something like Ekahau been completed?

You could be experiencing co-channel interference or non WiFi interference.

If you have the ability from the client you can see if the client is rate shifting when standing still this could indicate an issue.

I would leave all the MCS values turned on, and disable the legacy data rates if you want to change data rates.

Is it a particular type of client? is it always in the same position?

Just wondering if your able to if you turn one of the two APs off, do you still experience issues? As in is the issue related to when the client is trying to roam or when its static right under the AP.

[sasha]

Hi Haydn, I checked noise values and it turned out that there's a lot of noise on many channels, stronger than the threshold set in ME profiles. That could be the cause. Interference is also quite close to the threshold.

The same problem existed with just one AP. All devices are in one room approx. 7x11m, APs are on opposite sides. Clients are 17 PCs (HP with Intel WiFi) and 3 tablets (MS Surface Pro 5th gen). All devices are in fixed positions, even the tablets. Bluetooth keyboards and mice are used. Mobile base stations on approx. 30m. Microwave oven quite close, on the floor below. There was some rate shifting and roaming occasionally.

In the meantime I went down to 11a and the WiFi works stable now! What else can be done to improve stability in such situation? Thanks and best regards.