legacy client incompatibility with 2702 Access-points

[luckymike33]

Hi,

I wondered if anyone has any general advice on how to troubleshoot an issue we are seeing with a new wifi deployment using legacy clients (802.11a/b/g only) with a 5508 controller and 2702 access-points. The software version of the wireless controller is 8.0.140.0.

Basically we have good coverage throughout our deployment, having had both an initial survey and a post deployment survey.

The issue seems to be that some legacy clients (about 20) continually disassociate from the network. The cause is unknown - i.e. It is not clear whether they cannot roam or something else happens.

In the log buffer, the 2 messages we see over and over are below:

*dot1xMsgTask: May 14 20:39:48.126: %DOT1X-4-MAX_EAPOL_KEY_RETRANS: 1x_ptsm.c:509 Max EAPOL-key M1 retransmissions exceeded for client 00:10:20:4a:13:44

*apfMsConnTask_6: May 14 20:39:43.064: %APF-4-ASSOCREQ_PROC_FAILED: apf_80211.c:5991 Failed to process an association request from 00:10:20:4a:13:44. WLAN:1, SSID:NLC_SCANNERS. message with invalid supported rate.

Compared with the previous hardware (a ringmaster/juniper setup) - our 5508 is configured slightly differently, i.e. uses wpa2 with static key) (instead of WEP), we have different mandatory rates (18mbps on Cisco vs Juniper of 1,2,5.5 and 11) - all the remaining rates on the Cisco are supported, as they were on the juniper.  I know it looks strange to have a different mandatory rate set - but they do seem to initially associate at least.

Obviously I can also see that the logs are full of unsupported rates (which seems to suggest we have set a 'g' rate in an environment where there are 'b' only clients, but why would they still be able to associate at all?

One other major difference is that we have 802.11n enabled on the Cisco, whereas I think it was disabled on the Juniper setup (even though it was capable of it).

Can anyone suggest a way forward with this?

First thing in the morning I will enable a debug client [mac]for a specifc client, and post that too..

Best wishes

Mike

[Leo Laohoo]

Mike, 

Update the wireless drivers of the clients first.

[luckymike33]

Hi Leo,

Thanks for replying - I am still looking at this.

I am due a meeting later with the guys who support the clients, I plan to push strongly for a client update. In the meantime I have attached a debug of a client I see disassociating all the time, in case anyone fancies a look at it.

For my own benefit, I guess it would be nice to know why the clients worked ok with the ancient Juniper, but will not longer work properly with the Cisco controller solution.

Unfortunately I do not have enough wireless time/experience to understand 100% the logs.

Thanks

Mike

[Leo Laohoo]

%APF-4-ASSOCREQ_PROC_FAILED: apf_80211.c:5991 Failed to process an association request from 00:15:70:a7:0e:38. WLAN:1, SSID:NLC_SCANNERS. message with invalid supported rate.

Logs are filled with this.  

What I'd like to know is what data rates are disabled globally (and RF Group).

[patoberli]

Just to be sure, you don't use 802.11a/b only clients, right?

Because those clients can't work if the mandatory rate is >11 mbps.

Also, they don't work with WPA2 (that was typically added in 802.11a/g clients).

Based on your text I expect the answer is "no".

Something you maybe could try, in the 802.11b/g/n/ac -> Network properties, disable "Short preamble". Some legacy clients are incompatible with this. This will reduce the performance a little, but shouldn't matter with such old clients. This is also available in the 802.11a/n/ac properties.