Cisco 887 integrated AP802 frequent reloads

I’ve come across this issue on a number of occasions now. The symptom is the internal access point which ships with the C887VA-W routers, specifically the AP802GN-A-K9, frequently reloading, with no apparent reason.

There are two root causes I’m aware of. The first is outdated and buggy IOS software. There is a bug in one of the 12.4 versions which causes seemingly random reloads every ~20 minutes. It leaves behind a clue in the form of a traceback in the log. The fix is simple, update to 15.x.

The second is a misconfiguration, and the symptom is an AP reload every 15 minutes, with no logs or errors. Usually, it’s because the router’s wlan-ap 0 interface has an IP address which isn’t on the same subnet as the BVI 1 interface of the AP. Even though they may be able to reach each other, I suspect there is some L2 traffic happening where the AP module registers with the router.

A counter of these registrations can be viewed through the service-module wlan-ap 0 statistics command. Sample output below.

Those with a keen eye will spot the Registration request timeout reset count line. Thats right, if the AP module cannot register successfully, the router will reload the AP. The timeout is 15 minutes, and it’s enabled by default.

So what does registration give you? Here is the output of service-module wlan-ap 0 status command from a router with a successfully registered AP:

And, from a router with AP registration issues:

Configuration issues will typically result in the output of show service- module status (executed on the AP) showing the following:

A good configuration will have the module in a STEADY state.

There are two ways to fix this and stop the AP being reloaded every 15 minutes.

1. Fix the damn config (more on this later)
2. service-module wlan-ap 0 heartbeat-reset disable