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BR350 -- Lost Authentication with Parent

I have installed 4 BR350 bridges at a customer site. All works well except for two of the bridges. These bridges keep going down every 5 to 10 miniutes with an event in the log "Lost Authentication with Parent" on the parent bridge I get a message that says "Deauthentication from [Wireless01]004096520080, reason "Not Authenticated"". Reauthentication occurs and the bridges comes back up in about a miniute. I have looked at the singal strength and it is about 98% is as the quality. I am at a loss.... All of the bridges are on the same sw version (12.00T) but I am having the problem with only these bridges. As far as layout Bridge1 is assos. with Bridge2, Bridge3 is assos. with Bridge2 and Bridge4 is assos. with Bridge3.

Please Help.

6 REPLIES
Cisco Employee

Re: BR350 -- Lost Authentication with Parent

First thing to do is upgrade to 12.02T to avoid CSCdz03100

Next follow the steps from Nilesh in this previous post

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40%40.ee94d5e/5#selected_message

I would also have a look at your design, from what you have described you have 2 repeaters. This will mean your throughput will be reduced by about 75%

If you can have something like

----|--- Root bridge 1------ radio link----non root without clients----|---Root bridge 2----radio link------ Non root without clients

---|---- is a 10baseT ethernet link Then you will not have this reduction in throughput.

The reason repeaters reduce throughput by half for each step is they have to receive the packet then deframe error check then check the dest address the retransmitt this same packet, you are doing this on each link while contending for the same bandwidth at least in the setup above you can use 2 different channels and have 2 different radio networks

New Member

Re: BR350 -- Lost Authentication with Parent

I have completed the steps above. No good, still loosing connection. I have it set up as --10BT-----Non-root------Root------Root-------Non-Root----10BT--. When I raised the beacon timeout interval from 100 to 2000 the problem got much worse, so I moved it back to 100. All of the other steps I left in place but made no difference.

Cisco Employee

Re: BR350 -- Lost Authentication with Parent

Sounds like you have an RF link issue then.

What fade margin did you calculate when you did your link budget in your site survey ?

What signal strength and quality do you see when you do the antenna alignment test ? What channels are these on and what do you see on the link activity test ?

Do you have any obstcles in the path that may interfer with the fresnel zone ?

Where are the antenna mounted ? On the edge of the roof or set back fromn the edge like on a lift shaft etc ?

Have you tried a new coax ?

New Member

Re: BR350 -- Lost Authentication with Parent

The lowest singnal strength for the radios is around 55% and the singnal quality is 98% or above. I am running the radios on channel 9 but have tried all of the channels. The carrier busy test shows little to no noise (mostly none) on all channels and the carrier busy jumps around on each channel but maxes out at around 3 to 4 percent.

There are four antennas; 2 are mounted on free-standing towers, 1 is mounted to a telephone pole, and one is mounted to structure (concrete). There are 2 yagies, and two omni-directionals. They are layed out as follows:

yagi / tower-----------omni / tower------------omni / structure---------yagi / pole

The omni mounted to the structure is at the highest point of the structure. A flange plate is mounted horizontally to the roof facade, a 3' shaft in mounted in the flange and the omni is mounted to the shaft.

The coax cables at all locations have be inspected and tested for db loss. All test within spec.s.

We have direct line of sight with no obstacales.

I have to beleive I'm dealing with some sort of configuration problem or sw bug because both of the yagi locations keep getting the error.

Cisco Employee

Re: BR350 -- Lost Authentication with Parent

The omni mounted to the structure is at the highest point of the structure. A flange plate is mounted horizontally to the roof facade, a 3' shaft in mounted in the flange and the omni is mounted to the shaft.

Are you sure the roof of this structure is not in the fresnel zone ?? You will have to draw this out to scale and use trigonmetry to calculate the distance

Are you sure you have selected the correct antenna port in the config to the one you are using ?

Why did you select Omni in the 2 centre locations ?

What did you calculate your fade margin as when you did the link budget ??

New Member

Re: BR350 -- Lost Authentication with Parent

Try just for giggles raising the beacon interval to 5000. Remember it must be changed on all radios that will talk to eachother. Also, how long are the links and have you told the radios about the length of the connections?

-Mike

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