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Community Member

Client disconnects unexplained

We are having an odd problem with clients now that we've moved from WiSMs to a 5760 controller.  I'll try to address the basic questions in this post.

In one area of only one building (of 22 buildings), we have clients being disconnected from wireless randomly with no consistency that has been reported.  Clients are Apple & Windows, and they don't seem to have problems elsewhere.  We are unable to replicate the problem on demand, so must allow it to happen randomly.  Problem seems confined to one geographic area of the building on two different floors (problem areas are essentially stacked upon each other).

RRM reports no interference, no channel or Tx power change events taking place.  There is not a bandwidth issue on the multiple switches hosting the APs.  Controller is a 5760 running 3.3.4 (yesterday upgraded from 3.3.3 to see if it helped the problem).  APs are 3702i US version.  No previous problem in this area using Wisms and mix of 1042, 1142, and 1252 APs, all of which have been replaced with 3702.  That's when the problem began--new controller & APs.

DHCP doesn't appear to be a problem (remember, no issues elsewhere in the same building) idle timer has been increased from default.  The entire building is in the same wlan group, same VLAN, same DHCP, same SSID, same controller, same everything.  Yet the problem appears restricted to an area.  Multiple different switches involved, so it's probably not the switch or switch uplink.

Since DHCP, switches, bandwidth, and even the wlan group seem ruled out considering there are no problems elsewhere, what else would cause clients to just disconnect?  It's hard to track down since we can't replicate the issue.  We don't use ACLs, everyone is treated equally, and we have no VOIP running wireless or wired.  over 1,000 wireless users at any moment and only a few in one corner are having problems.  Our total wireless bandwidth use is under 100Mb each direction aggregate during its busiest.  All APs are connected with gigabit.  Sounds like interference, but the APs aren't complaining.  Fortunately, wireless isn't our primary means of connecting clients.

Baffled and confused.

Community Member

If the SSID is configured to

If the SSID is configured to use TKIP, there remains the possibility that bug ID CSCuo97883 is a factor when clients are connected to this WLAN on a 3700 series access point. The bug gives you options but they did not work for us, but our disconnects are specific to the 3702i. Hope this works or you get an answer.

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