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New Member

Help with PC associating to a far away access point

We have an issue in a training room where 4 Dell all in one PC's sometimes have wireless issues.  We relocated the AP to directly above the 4 PC's instead of the hallway outside of the training room because off that hallway there is also a lunch room with two microwaves, so we thought that was interfering.

 

Anyway sometimes one or two of the PC's in this training room fall off the wireless or they must be associating with the AP on the 3rd floor causing the latency to go in upwards of 1900ms in ping times to the machine.  Rebooting the PC will usually bring it back to the AP directly above it, resulting in ping times of 1-3 ms.

 

I drew up a very summarized diagram and what I am thinking is happening is that the wireless signal is bouncing around an emergency stairwell located in the back of the building that has direct access to the 3rd floor, and also that AP on the 3rd floor is at that end of the building near that stairwell.  Employees don't use this stairwell, there's two others and also an elevator in the building.

 

We have a 5508 WLC running on 7.4.121.0 and 6 AP's in this building.  Just curious if there is anything I should be checking on the WLC, or do you think this is a PC network card problem where I should be checking drivers, etc...

 

We could throw a small switch in there and hard wire them, but we got all in ones with wireless because the desks are on castors and being that it is a training room, sometimes they like to move things around in there.

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Hall of Fame Super Gold

Make sure your TPC and DCA

Make sure your TPC and DCA are set to enable. 

 

Change the Data Rates of the AP:  Disable all data rates from 11 Mbps and below.  make 18 Mbps as Mandatory and the rest are Supported.

New Member

Ok, I checked for both 802

Ok, I checked for both 802.11a/n and 802.11b/g/n,

TPCv1 checked.

Power level assignment method - automatic every 600 secs

Maximum power level assignment 30

Minimum power level assignment 11

Power threshold -70

 

DCA for 802.11a/n -

Channel assignment method - Automatic - Interval 10 minutes - AnchorTime 0

Avoid Foreign AP Interference - Enabled

Avoid non-802.11a noise - Enabled

DCA Channel Sensitivity - Medium

Channel Width 40 MHz

DCA Channels: 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 132, 136, 140, 149, 153, 157, 161

Extended UNII-2 Channels enabled

Event Driven RRM Enabled, Sensitivity Threshold - Low

DCA under 802.11b/g/n

Channel assignment method - Automatic - Interval 10 minutes - AnchorTime 0

Avoid Foreign AP Interference - Enabled

Avoid non-802.11b noise - Enabled

DCA Channel Sensitivity - Medium

DCA Channels 1,6,11

Event Driven RRM - Enabled

Sensitivity - Low

 

 

Now lets look at data rates.

802.11a global parameters

6,9,12,18 mbps all disabled

24 mbps Manditory

36,48,54 mbps Supported

Beacon Period - 100

Fragmentation Threshold 2346

DTPC Support - Enabled

Maximum Allowed Clients - 200

802.11a band status Low, Mid, High all enabled

CCX Location Measurement - enabled - 60 seconds

 

802.11b/g global parameters

1,2,5.5,6,9 mbps - disabled

11 mbps - Manditory

12 through 54 Mbps - Supported

802.11b/g network status and 802.11g support - enabled

Beacon - 100 ms

Short Preamble - Enabled

Fragmentation Threshold - 2346

DTPC Support - Enabled

Maximum Allowed Clients - 200

CCX Location Measurement - Enabled - 60 seconds

 

Now for the SSID these systems are connecting to,

Client load balancing is unchecked

Client band selected is checked

Coverage hole detection is enabled

MFP Client Protection is optional

DTIM Period is 1 for both a/n and b/g/n

 

 

In the trap logs, some of the things I see frequently are:

Interference Profile Failed for Base Radio MAC: 58:35:d9:39:5b:40 and slotNo: 0

Coverage hole pre alarm for client[1] c0:63:94:52:01:cc on 802.11b/g interface of AP 58:35:d9:39:5b:80 (AP3). Hist: 46 14 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Interference Profile Updated to Pass for Base Radio MAC: 50:1c:bf:80:5f:d0 and slotNo: 0

And also a bunch of Rouge AP detected or removed from Base Radio MAC.

 

Hope some of this information helps.  It seems that the training room computers have more difficulty when there are people next door with 4 laptops.  Still that would only be 8 clients on one AP.  That AP has a 1 gig connection to a 3750 switch port.

 

New Member

I even moved up Manditory to

I even moved up Manditory to 24 Mbps and disabled everything below it.  Still an issue.

 

So I went into device manager and properties for Dell Wireless 1540a/g/n and the advanced tab.  I changed Roam Tendancy from Moderate to Conservative, then Roaming Decision from Default to Optimize Bandwidth.  I clicked OK.  I was remote into the machine and lost the connection.  I was able to reconnect (it was MUCH faster).  I refreshed the clients screen in the WLC and this particular PC went from the 3rd floor access point, to the access point right above the physical PC.  So I am going to make this change to all 4 PC's right under that access point and see if that helps.

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