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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
Misconfiguration of BGN
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.
In order to recover such a stranded mesh access point, the concept of default bridgegroupname has been
introduced in the software. Therefore, 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 scan and find 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, attempt connecting with default bridgegroupname using AWPP.
4.
For each failed attempt in Step 3, exclusion-list the neighbor and attempt to connect the next best
neighbor.
5.
If the AP fails to connect with all neighbors in Step 4, reboot the mesh access point.
6.
If connected with a
default
bridgegroupname for 15 minutes, the mesh access point will go into a
scan state.
When an mesh access point is able to connect with the default bridgegroupname, the parent node reports
the mesh access point as a default child/node/neighbor entry on the controller, so that a network
administrator is Cisco WCS. Such a mesh access point behaves as a normal (non-mesh) access point and
accepts any client, other mesh nodes as its children, and it can pass any data traffic through.
Note
Do not confuse an unassigned BGN (null value) with DEFAULT, which is a mode the access point uses
to connect when it cannot find its own BGN.
To check the current state of an mesh access point’s BGN, enter this command (CLI):
(Cisco Controller)>
show mesh path Map3:5f:ff:60
00:0B:85:5F:FA:60 state UPDATED NEIGH PARENT
DEFAULT
(106B), snrUp 48, snrDown 48, linkSnr
49
00:0B:85:5F:FB:10 state UPDATED NEIGH PARENT BEACON (86B) snrUp 72, snrDown 63, linkSrn 57
00:0B:85:5F:FA:60 is RAP
To check the current state of a mesh access point’s, check neighbor information for the mesh access point
(GUI):
Select
Wireless > All APs >
AP Name
>
Neighbor info
(
and