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Cisco Aironet 1520, 1130, 1240 Series Wireless Mesh Access Points, Design and Deployment Guide, Release 6.0
OL-20213-01
Troubleshooting
The following steps are automatically initiated at the controller when a mesh access point loses its
connection to the controller:
•
Identifies MAC address of stranded mesh access point
•
Finds a nearby neighbor that is CAPWAP connected
•
Sends commands through remote debug
•
Cycles channels to follow the mesh access point
User only has to know the MAC address of the stranded AP to make use of this feature.
A mesh access point is considered stranded if it goes through a lonely timer reboot. When the lonely
timer reboot is triggered, the mesh access point, which is now stranded, enables passive beaconing, the
anti-stranding feature.
This feature can be divided into three parts:
•
Strand detection by stranded mesh access point
•
Beacons sent out by stranded mesh access point
–
Latch the 802.11b radio to a channel (1,6,11)
–
Enable debugs
–
Broadcast the standard debug messages as distress beacons
–
Send Latest Crash info file
•
Receive beacons. (Neighboring mesh access point with remote debugging enabled).
Deployed mesh access points constantly look for stranded mesh access points. Periodically, mesh access
points send a list of stranded mesh access points and SNR information to the controller. The controller
maintains a list of the stranded mesh access points within its network.
When the command "
debug mesh astools troubleshoot <mac-addr> start
" is run, the controller will run
through the list to find the stranded mesh access point
mac-addr
A message is sent to the best neighbor to start listening to the stranded access point. The listening mesh
access point will get the distress beacons from the stranded mesh access point and sends it to the
controller.
Once a mesh access point dons the role of a listener, it will not purge the stranded mesh access point
from its internal list, until it stops listening to the stranded mesh access point. While a stranded mesh
access point is being debugged, if a neighbor of that mesh access point reports a better SNR to the
controller than the current listener by some percentage, then the listener of the stranded mesh access
point is changed to the new listener (with better SNR) immediately.
End user commands are below:
•
config mesh astools [enable/disable]: This command will enable or disable the astools on the mesh
access points. If disabled, APs will no longer send stranded AP list to the controller
•
show mesh astools stats: This command shows the list of stranded APs and their listeners if they
have any
•
debug mesh astools troubleshoot <mac-addr> start: sends a message to the best neighbor of the
<mac-addr> to start listening
•
debug mesh astools troubleshoot <mac-addr> stop: sends a message to the best neighbor of the
<mac-addr> to stop listening
•
clear mesh stranded [all/<mac of b/g radio>]: clears stranded ap entries
Controller Console will be swamped with Debug messages from stranded APs for 30 minutes.
