AP1522 changing parent node very frequent & 2 RAPs are creating a loop

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Dec 18th, 2008
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i have 2 issues..

i have 7 units of AP1522 installed, 2 units as RAP and 5 units as MAP. The system is up and running. i have the following problem.

1) The MESH AP changing the parents every now and than.

2) My 2 RAPs connection has been deteced as a loop at my CE500 Switch and on port will be blocked.

following msg from cotroller "(Cisco Controller) >Thu Dec 18 12:41:06 2008: spamMeshExcessiveParentChangeAlarm :: Mesh AP 00:23:05:2D:AC:00 changed a parent 3 times within 60 minutes.

Thu Dec 18 12:41:37 2008: spamMeshExcessiveParentChangeAlarm :: Mesh AP 00:23:05:2C:EB:00 changed a parent 3 times within 60 minutes."

has anyone came across this situation on 2 RAPs before.

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dennischolmes Mon, 12/22/2008 - 09:24
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Install RAPs on separate switches or VLANs as a spanning tree loop will commence if you don't. The APs changing parents is based on an algorithm that assigns the best path for traffic and backhaul. Changing parents once a day in not necessarily bad. Changing every fifteen minutes would be indicative of a poorly designed backhaul link. This would indicate that the usual primary link is experiencing difficulties due to low signal, interference, or noise. When this occurs the AP on the remote end will reboot and restablish backhaul to an alternative parent. You need to look for the RF problem between the APs.

mohanantassp Wed, 12/24/2008 - 00:11
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Hi Dennis, thanks for your brief info, i have tried all those thing and the spanning tree loop problem is now solve in the latest release XX.35M.

Now when i have 2 RAP connected to CE500, all AP and controller working fine but when i unplug 1 unit of the RAP from the CE500 switch i fond that both RAP link is down. in some tries 1 RAP come up again after about 15 to 20 min and some times my mesh link is fully out from the controller. Can i assume that when i unplug 1 RAP the other RAP works as the primary and make connections available.

Am i correct to say that when i have 2 RAP in the mesh network, both work at the same time 1 fails also another one works find.

Please advice me if anyone came across this situation.

dennischolmes Wed, 12/24/2008 - 08:16
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It is a best practices design to sectorize your network into four sectors. Each on a different channel. Mechanisims within the code allow the APs to find alternative routes when necessary due to a RAP failure. Both units must be set in the role of RAP for your design to work. If they are failing it is probably a bridgegroup name issue or one AP is in the wrong role (MAP). Also, insure date and time are correct on the controller.

mohanantassp Thu, 12/25/2008 - 23:20
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hi dennis, thanks for your reply.

i have attached a config details here for your references. hope you can feedback based on the config details.

I have created the bridge group names in 1 group and the channel assignment was by the controller. By default my RAP was assigned with 2 different channels by the controller. i have enable the ethernet bridging in 1 RAP. its just the failover is very slow and if i disconnect of the RAP from the CE500 switch both RAP link are going down. i have configured the smartport in the ce500 switch to "access point" mode. please advice if i require more configurations.


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