Connectivity issue with AP541N-K9

[mullness]

Hey there,

I have a customer who has 2x AP541-K9 with the latest firmware installed. They are setup in a cluster and share one lan. The customer is experiencing problems with connecting and sudden drops of connectivity. The customers has given us feedback that in many instances they are not assigned an IP adress over the WLAN or that it is very unstabel and they experiece losing connectivity even with excellent signal and little intereference. After some troubleshooting we have seen that clients are dropped from the AP after a few minutes, see logg under for example.

“wlan0: IEEE 802.11 STA 18:e7:f4:fe:26:79 deauthed from BSSID 64:ae:0c:ed:64:f0 reason 3”

I am also attaching part of an eventlogg from one of the AP's dropping connectivity.

Advise here would be much appreciated.

Kind regards,

Morten

[Leo Laohoo]

Logs doesn't give me any distinctive indication as to why.

Can you provide more information?

1.  What is the signal strength seen from the WAP to the client?

2.  What is the signal strength seen from the client to the WAP?

3.  What kind of Apple device is this? 

[DaniB_PCEX]

Thanks to Morten for creating the topic, l`ll answer any follow-up question regarding the issue.

1.  What is the signal strength seen from the WAP to the client?

Unsure how you would measure this from the access point, could you please elaborate?

2.  What is the signal strength seen from the client to the WAP?

Since this applies to most of the appliances in this network we have seen it happen for people sitting just a few feet away from the AP and others with medium to low quality signal strength. If you require statics and more information regarding this and the first question we will try to acquire it.

3.  What kind of Apple device is this? 

This problem is mostly for devices running Windows OS but some handheld Apple devices such as phones and pads are experiencing this as well.

[Leo Laohoo]

1.  I'm no expert on the 540 but is there a GUI to show you the RSSI value from the WAP to a client?

2.  Ok, so not just Apple clients but across the board.  What band are these clients having issues connecting on?  a/b/g?

[Eric Moyers]

Hi, My name is Eric Moyers. I am a Network Support Engineer in the Cisco Small Business Support Center.

Sorry to jump in mid conversation guys, but the one product that can do what your looking at is the program InSSIDer.

http://www.metageek.net/products/inssider/

It is a free download.

Not can you see the RSSI, but it will give you information about the other wireless in your area that could be contributing to your connectivity issue. I am attaching a document that I put together for the engineers in the support center to help them with reading and interpreting the scans.

Let me know if I can help.

Thanks

Eric Moyers    .:|:.:|:.

Cisco Small Business US STAC Advanced Support Engineer

Surveillance and Wireless SME

CCNA, CCNA-Wireless

866-606-1866 ext 601027

Mon - Fri 09:00 - 18:00 (UTC - 05:00)

[DaniB_PCEX]

Thanks for responding both of you.

To answer you Leo first;

1.      I'm no expert on the 540 but is there a GUI to show you the RSSI value from the WAP to a client?

Yes there is, it shows signal strength (in dB I would guess?) and data rate in Mbps. I`ll will try over the next few days to get the users to report to me so I can get some more data on how the signal strength is related to those experiencing disconnects.

Just for an example the ..26:79 address you can see in the previous logs show a signal strength in the low 50`s range.

2.      Ok, so not just Apple clients but across the board.  What band are these clients having issues connecting on?            a/b/g?

For the moment we are running the system on 802.11b/g just to narrow down the problems by avoiding A for now. We have tried running the system on 802.11a/n but with no better result.

And thanks Eric, all help is appreciated! I`ll take a look on that document tomorrow morning regarding interference from other sources. Just to add we have done some measuring in the building and selected channels for the AP as far as possible from other WLAN`s. Disturbance from other WLAN`s should be minimal from what I could tell last time we checked the building. Anyhow I will take a look at it again since much might have changed the last few months.

[DaniB_PCEX]

Hello again, just a follow-up with some more information on the case.

The issue seems to be less of a problem now then it was earlier this year but still occurs from time to time. For about 4/5 cases the solution would be to disable then enable the Wireless network interface that is connected to the WLAN. This would point to difficulties with receiving DHCP/IP information over the WLAN?