APXBS freezing

[grekelltech]

APXBS Troubleshoot

Situation
Two new Airport Extreme Base Stations, updated to firmware 5.7. They are a single network and bridging from the LAN. WEP is active and the network is closed. The stations are located 18 paces, or about 45 feet, apart in a commercial office building, slab above and below. Network is created with a Cisco PIX 506e providing NAT and DHCP. All local interference devices distant or out of band.

Symptom
Intermittently, either or both extreme base stations lose wireless connectivity. When this “freeze” happens, the base station is not visible to admin utility on either wired or wireless connection. The status bars stay full on connected clients, but there is no connectivity. If the other base is running OK, turning off airport card and back on gets the clients to roam to the running base station. The hang also manifests in the LED display; the left light is out, the middle on, the right one blinking. This is said to mean the wireless side is not functioning. Cycling power on the base station brings it back up running fine for hours or days. If monitoring with Airport Management Utility, the utility freezes also when the APXBS freezes.

Attempted fixes:
-Using WAN uplink or LAN uplink to rule out routing (?)
-interference robustness, each APXBS and both at same time.
-transmit power decrease, each APXBS and both at same time.
-setting channel manually with 1-6 spread
-set up logging to wired system.log-no useful info. Crash terminates all efforts to monitor by APAU or AMU.
-checked MacStumbler for other networks found 7, mostly on channel 6, one on channel 11 strongest. Reset channels for non-conflict.
-Replacing both base stations.
-turned off one unit and monitored running unit with Airport Management Utility. This app became unresponsive when the base unit “hung.”
-turned one BS off and set the other by hard reset and had it distribute a range of IP addresses.

Next Steps
Bypass as much of the switch fabric as possible and patch the APXBS drop close to the firewall.

I do not know of packet sniffing can help, since this may be physical layer, and I do not know how to analyze this without much study.

[grekelltech]

Apple answers thus:

Unfortunately, the only workaround I can provide for you at this time is to revert these Base Stations to firmware 5.5.1. Apple Engineering has received reports of this symptom and are currently investigating. Further updates, if any, may come by way of a software update, knowledge base article, or software release.

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