Need help debugging issues with client exclusions and coverage holes

Unanswered Question
Nov 7th, 2007

For awhile now I have been fighting a losing battle with many clients getting excluded for unknown reasons and coverage holes appearing in random places.

I'm in a campus environment with 133 access points.

The campus layout is quite scattered and disorganized- it was built over older buildings for the most part, but the old buildings are still there. This is part of the problem.

As for the equipment I use- I'm using WCS version 4.1.83.0 and two 4404 controllers on version 4.1.171.0. The Access Points are 1010 and 1020 running over L3 LWAPP.

Just to clarify on some of the errors I'm recieving (taken out of the WLC trap logs):

0 Wed Nov 7 12:16:48 2007 Coverage Hole Detected for AP 1C QUAD whose Base Radio MAC is 00:0b:85:62:11:20. Number of Failing Clients 1

1 Wed Nov 7 12:15:04 2007 Coverage hole cleared for Base Radio MAC: 00:0b:85:64:1a:50 and slotNo: 1

2 Wed Nov 7 12:14:39 2007 Interference Profile Updated to Pass for Base Radio MAC: 00:0b:85:64:23:a0 and slotNo: 1

3 Wed Nov 7 12:14:18 2007 Coverage hole cleared for Base Radio MAC: 00:0b:85:59:e4:70 and slotNo: 1

4 Wed Nov 7 12:14:13 2007 Load Profile Failed for Base Radio MAC: 00:0b:85:55:69:c0 and slotNo: 1

5 Wed Nov 7 12:13:24 2007 Client Association Failure: MACAddress:00:12:f0:94:a8:7f Base Radio MAC:00:0b:85:64:23:a0 Slot: 1 Reason:Unspecified ReasonCode: 1

6 Wed Nov 7 12:13:18 2007 Interference Profile Updated to Pass for Base Radio MAC: 00:0b:85:55:69:e0 and slotNo: 1

7 Wed Nov 7 12:12:04 2007 Coverage Hole Detected for AP 1L42 whose Base Radio MAC is 00:0b:85:64:1a:50. Number of Failing Clients 3

8 Wed Nov 7 12:11:39 2007 Interference Profile Failed for Base Radio MAC: 00:0b:85:64:23:a0 and slotNo: 1

9 Wed Nov 7 12:11:18 2007 Coverage Hole Detected for AP Riddell Cafeteria East whose Base Radio MAC is 00:0b:85:59:e4:70. Number of Failing Clients 2

10 Wed Nov 7 12:11:13 2007 Load Profile Updated to Pass for Base Radio MAC: 00:0b:85:55:69:c0 and slotNo: 1

11 Wed Nov 7 12:10:18 2007 Interference Profile Failed for Base Radio MAC: 00:0b:85:55:69:e0 and slotNo: 1

12 Wed Nov 7 12:09:16 2007 Load Profile Updated to Pass for Base Radio MAC: 00:0b:85:62:c5:40 and slotNo: 1

13 Wed Nov 7 12:08:27 2007 Coverage hole cleared for Base Radio MAC: 00:0b:85:62:ca:b0 and slotNo: 1

14 Wed Nov 7 12:08:22 2007 Client Excluded: MACAddress:00:1c:26:02:df:bf Base Radio MAC :00:0b:85:55:52:30 Slot: 1 Reason:802.1x Authentication failed 3 times. ReasonCode: 3

15 Wed Nov 7 12:05:39 2007 Coverage Hole Detected for AP 2L02 whose Base Radio MAC is 00:0b:85:64:19:90. Number of Failing Clients 1

16 Wed Nov 7 12:05:27 2007 Coverage Hole Detected for AP 5CM18 whose Base Radio MAC is 00:0b:85:62:ca:b0. Number of Failing Clients 1

17 Wed Nov 7 12:05:11 2007 Coverage hole cleared for Base Radio MAC: 00:0b:85:55:c9:00 and slotNo: 1

18 Wed Nov 7 12:03:41 2007 WPA MIC Error counter measure activated on Radio with MAC 00:0b:85:55:5d:90 and Slot ID 1. Station MAC Address is 00:13:02:e0:9f:81 and WLAN ID is 7.

19 Wed Nov 7 12:03:08 2007 Interference Profile Updated to Pass for Base Radio MAC: 00:0b:85:55:50:80 and slotNo: 1

20 Wed Nov 7 12:03:04 2007 Coverage hole cleared for Base Radio MAC: 00:0b:85:64:1a:50 and slotNo: 1

Any input would be -greatly- appreciated. This is just a few of the many issues I have been fighting with in this environment for wireless, but it's arguably the most important one to figure out.

I have this problem too.
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bbxie Thu, 11/08/2007 - 21:38

from the log, there's a coverage hole found every few minutes,there are 3 possible reasons for it:

1. Not enough APs installed, this can be checked by doing a site survey. try to add more APs according to the site survey.

2. Heavy multi-path reflection, since it is built over old buildings, it may be the major cause. try to replace some 1010 with 1242(of-course using diversity external antennas)especially those places that often detect coverage hole

3. Cisco's AutoRF may have some bugs here or you mis-configured the threashold for AutoRF. double check those threashold or disable AutoRF and mannually set the channel and Tx power level.

dennischolmes Mon, 11/12/2007 - 13:51

Jeff,

bbxie is probably correct on the density of access points. If you can do a planning mode proposal and let me see how your maps were configured I might be able to give you some pointers. First of all, make sure you have the walls properly attenuated in your WCS maps. Without this, you can't get a good gui visual of what the network really looks like. Next, set you RSSI cutoff to -70 if data, -68 if voice, and -65 if location services are desired. Another quick way to tell if you are underdeployed is to look at the current power assignments for the APs. If they are at highest power you are underdeployed. You should be powered at about 60% power. I have extensive experience with the 1000 series APs and can help you redesign if necessary.

jmagnusson Mon, 11/26/2007 - 09:22

Uprage 40 4.1.185 or move to 4.2.61. Auto Rf is much MUCH better behaved.

before those codes I have 50X the auto RF changes that I do now.

Once there reevaluate..

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