Wireless Access

Environment:

- Fulfillment Center (215,000sqft)

- 26x AP 134's 3x AP214

- Controller ArubaOS (MODEL: Aruba3600-US), Version 6.4.2.18

- RF Devices: Motorola MC3190, MC32N0, WT41N0

 

Summary:

 

These HHD's (hand held devices) have historically been problematic with users reporting wireless connectivity issues (dropping of the network).  I have scoured these Airhead threads to find input and have tried all advice in this thread:

https://community.arubanetworks.com/t5/Wireless-Access/Constant-dropouts-for-our-Motorola-Symbol-Scanners-MC9090G/td-p/241524

and additionally put my ARM g and a into Maintain mode

 

Interesting log statements:

 

authmgr[1860]: <132093> <ERRS> |authmgr|  WPA2 Key message 4 from Station 00:23:68:e7:26:6e b4:5d:50:88:fc:21 PGH-FC-AP30-c0:8f:c2 did not match the replay counter 01 vs 02

 

authmgr[1860]: <522027> <WARN> |authmgr|  MAC=00:23:68:cd:69:b8 IP=10.1.80.242 IP Spoof from MAC=00:23:68:cb:bc:5f role=authenticated/(null)

 

-Band steering is enabled

-Backoff Time = 1800

-Error Rate Threshold 75%

-Error Rate Wait Time 90 sec

 

We experience these drop offs every day.  Sometimes they effect the work stream more sometimes less...  Any help is welcome!

 

Thanks,

 

rif

"did not match the replay counter" typically means possible interference.

 

Are those devices running on the 2.4ghz or the 5ghz band?

Hi Colin,

 

The quick answer is that most of them use "g" and in the past we went through all of them to configure them to use g and a but as I was troubleshooting one this morning I noticed it was only configured to use "g" so at this point I do not know how many are configured thusly.  I need to go through them all manually to check.

 

rif

Okay.  Do you have a screenshot of the Dashboard> Performance Page?

Please see attached screen shot...

You have some APs where the channel busy is high.  See if those APs correspond to the areas where you are having problems.  You would then look to see if it is cochannel interference that could be causing that...

Thank you Colin, looking now...

 

rif

Colin,

 

Yes, a few of those WAP's are in an area where drops are reported.  Although the number of WAP's in that channel busy catagory changed mid observance to 4 from 6.  Two are on channel 11 and two are on channel 1

 

rif

now the count went up to 7.  should i look at rolling back to single-band from Maintain mode?

No, don't change anything.  You would want to go to where one of those access points are and see what the coverage is like using Aruba utilities (how many APs can be seen).  If there is a lot of coverage, you could consider turning down the ARM max transmit power for that band by 3 and see if it makes a difference in coverage and on the dashboard.

 

What is your ARM min and max transmit power for the 2.4ghz band?  Do you have broadcast filtering enabled?

min is 9 max is 15 and they are ALL at 9.  remind me where to find broadcast filtering?  i do believe that has been enable but I'd like to double check.  Also, I am not familiar with "Aruba utilities"

 

thanks,

 

rif

Is that for the 2.4ghz band (9)?  Broadcast Filtering should be on the Virtual AP profile...

yes 9 is the min for 2.4.  as far as Broadcast Filtering goes I do not see that exact function under the VAP rather is see:

 

Drop Broadcast and Unknown Multicast
Convert Broadcast ARP requests to unicast

 

could it be somewhere else?

 

rif

It is "Drop Broadcast and Unknown Multicast"

Yup already had that checked (enabled)
Also what was that about aruba utilities?

Rif

Aruba Utilities is an Android app that will tell you the signal strength of surrounding access points from the client perspective. It gives you and idea of coverage.

I will check that out. Any other thoughts?

Rif

Not right now, but I'm just guessing.  I would open a tac case in parallel.

In troubleshooting this RF device "dropping" problem I've been asked to run long term packet captures on a WAP.  In the past I've sent the capture data to my Mac running wireshark.  I cannot use my Mac as a long term destination for the capture data.  Is there a way to leverage the controller or Airwave for a long term packet capture?

 

rif

What make/model are these devices with the dropping issue?  

RF Devices: Motorola MC3190, MC32N0, WT41N0

Does anyone know a good debug option for seeing if anykind of scanning or channel negotiation (ARM in Maintain Mode) could be responsible for Handheld RF devices losing connectivity (WPA2 PSK SSID)

 

Thanks,

 

rif

Hi,

did anyone find the problem? is this fixed?

I am not really sure if we ever found one single problem...