been configured with a new channel or not. In order to overcome this, configure the mesh access point with
a new channel, and reboot the mesh access point.
Once radar is reliably detected on a channel, that channel, and the two surrounding channels, should be added
to the RRM exclusion list, as follows:
(Cisco Controller) >
config advanced 802.11a channel delete channel
A mesh access point goes to a new channel that is picked by RRM, and it does not consider excluded channels.
If a radar is detected on channel 124, for instance, channels 120, 124, and 128 should be added to the exclusion
list. In addition, do not configure RAP to operate on those channels.
Good Signal-to-Noise Ratios
For European installations, the minimum recommendation is increased to 20 dB of signal-to-noise ratio (SNR).
The extra dBs are used to mitigate the effects of radar interference with packet reception, which is not observed
in non-DFS environments.
Access Point Placement
Collocated mesh access points should have a minimum of 10 feet (3.048 meters) of vertical separation or 100
(30.48 meters) feet of horizontal separation.
Check Packet Error Rate
Mesh access points that have an high error rate, greater than 1 percent, should have mitigation applied to them,
by changing the channels for noise and interference, adding additional mesh access points in the transmission
path, moving the mesh access points to different sectors, or adding additional mesh access points.
Bridge Group Name Misconfiguration
A mesh access point can be wrongly provisioned with a
bridgegroupname
and placed in a group other than
it was intended. Depending on the network design, this mesh access point might or might not be able to reach
out and find its correct sector or tree. If it cannot reach a compatible sector, the mesh access point can become
stranded.
To recover a stranded mesh access point, the concept of default bridgegroupname has been introduced in the
software. When a mesh access point is unable to connect to any other mesh access point with its configured
bridgegroupname, it attempts to connect with the bridgegroupname of
default
.
The algorithm of detecting this strand condition and recovery is as follows:
1
Passively scans and finds all neighbor nodes regardless of their bridgegroupname.
2
The mesh access point attempts to connect to the neighbors heard with
my own bridgegroupname
using
AWPP.
3
If Step 2 fails, attempts to connect with default bridgegroupname using AWPP.
4
For each failed attempt in Step 3, it adds the neighbor to an exclusion list and attempts to connect the next
best neighbor.
Cisco Mesh Access Points, Design and Deployment Guide, Release 7.3
220
OL-27593-01
Troubleshooting
Bridge Group Name Misconfiguration
