ZF7372 High Client Density issue

[wlangeek]

Hi Everyone,

I'm evaluationg the zf7372 as a potential replacement for some 2942's and 7363's that I use in a very high density environment. We typically budget 75-85 stations per radio on the current AP's we have. From the documentation on the 7372 it looks like it can handle 250 stations per radio and I'd really like to present a case for upgrading to reduce protocol overhead by reducing the number of AP's, but I need to get a proof working in the lab first.

I've setup a testing environment in one of my labs, and have only been able to get ~120 devices to associate before the AP stops accepting associations. The logs on the attached ZD1100 show "User [DEVICE_MAC] fails to join WLAN [WLAN_NAME] from AP[AP_MAC]"

I've done a little more snooping using some of the tools I have and it appears that once I hit this ~120 device limit, the newer devices are able to associate, but are immediately (within ~7ms) sent a deauth frame. This testing environment is an open/WEP64 wlan, so I don't think I'm running into memory or other resource issues on the AP during the negotiation phase, but I could be wrong. I've looked at the AP logs and they show that the AP has plenty of memory remaining (60+MB)

I'm running 9.6.0.0.267 on a zf1100 with the same release on the AP.

The logs on the AP show the following errors once I reach the ~120 device range and start to see the deauth frame response to new clients:

Aug 12 23:35:04 RuckusAP user.info kernel: tac_set_station_key(): tac_set_station_key: new key failed
Aug 12 23:35:04 RuckusAP user.info kernel: net80211_tac_cfg_sta_add(): add station {DEVICE_MAC} session key,failed cipher = 2
Aug 12 23:35:04 RuckusAP user.info kernel: tac_set_station_key(): tac_set_station_key: new key failed
Aug 12 23:35:04 RuckusAP user.info kernel: net80211_tac_cfg_sta_add(): add station {DEVICE_MAC} session key,failed cipher = 2
Aug 12 23:35:04 RuckusAP local2.err syslog: Failed add station in processing MSG_MOBILE_CFG_REQ

I've tried disabling all the features I can to narrow down the issue, but I haven't had any luck (background scanning on/off, dropping multicast packets on/off, client load balancing on/off, client fingerprinting on/off, only one wlan active on the AP, etc). I've also ensured that the device limits are set higher than 120 clients so I don't believe I'm running into an issue there. I also don't see any warnings about reaching 90%+ of the AP's capacity as I generally do when I approach the limits on a 7363 device which also leads me to believe that it's a software issue and not a misconfiguration.

Anyone have some pointers on what might be going on here? It's starting to look like a bug in the AP firmware somewhere in the key management subsystem to me.

~WlanGeek

[wlangeek]

Hi Michael,

I've tried WPA2 with AES and seem to be hitting a limit at ~112 clients with a similar message to the WEP case in the AP's onboard logs. When you said WPA type clients were you refering to all the WPA versions, or only to WPA (and excluding WPA2)?

[wlangeek]

ttt

[craig_black_585]

Another one here on 9.6.0.0... WPA2 with AES, ~112 clients then the super quick auth / deauth... ZF7982 APs, more than capable of handling this number of clients... In fact, they do, but no more than 112 on the WPA2 WLAN... HELP?!

[wlangeek]

@Craig, Are you able to get more than 112 clients with some kind of encryption associated with an AP (eg 100 WPA2 and 100 WEP)? I'm starting to wonder if the 250device/radio claim only applies when you're not running any kind of encryption or security and there's still a ~100 device limit when you're running something other than a completely open network. Anyone from Ruckus want to chime in here?

[wlangeek]

Soo...ruckus...where are you guys? This seems like a pretty simple question to answer. This doesn't give me warm fuzzies about becoming a ruckus customer.