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Occasional Contributor II
Posts: 15
Registered: ‎09-28-2010

lost pings with PDA's on 802.11b/g

Hi,

We have some PDA's with summit radios. The customer complains about losing connection with their server.

I have noticed very frequent losing pings to the PDA. 

The encryption is WPA-psk/tkip .

I have checked and tested several things:

- there was no interference

- configured a new specific ssid on a specific accesspoint with no encryption 

- disabled ARM

- disabled a-radio

 

We have 6000 controllers with version 6.1.2.4 

The summit driver version is v2.03.47

There was a simmilar issue reported on this forum in 2011 , the solution then was to downgrade to 6.1.1.0

This isn't realy a option for us.

 

Are there any new options to solve this problem?

 

thanks in advance,

Anton

Guru Elite
Posts: 21,270
Registered: ‎03-29-2007

Re: lost pings with PDA's on 802.11b/g

I would ensure that you do not have wired and wireless traffic on the same layer2 subnet.  That could definitely punish your wireless traffic and cause the contention issues you mention.

 

If you are forced to have both on the same subnet, you should enable "Drop Broadcast and Multicast" on all of your Virtual AP profiles to ensure that broadcasts do not cause contention.

 



Colin Joseph
Aruba Customer Engineering

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Aruba
Posts: 161
Registered: ‎04-03-2007

Re: lost pings with PDA's on 802.11b/g

 

Can you find out what the max TX power is of the Summit radios?   They make/made radios with a very wide range, from as low as 25mW if memory serves up to 100mW.   Many of our customers have low power radios in their units since they were cheaper than the high power radios.  

 

You could easily have a big power mismatch between the AP and the client.   If so, this can only be corrected by increasing density.

 

You might also try disabling higher rates, start with turning off 48 and 54.   Maybe even 36.  These rates don't travel very far.  See if you can stabilize the connection at low rates.   Again, this will tell you something about the power symmetry between AP and client.

 

If the power levels are matched, then you're looking at driver interop.

 


-cl
Occasional Contributor II
Posts: 15
Registered: ‎09-28-2010

Re: lost pings with PDA's on 802.11b/g

Thanks for your fast response!

 

In answer to cjoseph:
We do have traffic on the same layer 2 subnet, but this subnet is very small with just a view hosts in it.
I have made the change with the Broadcast as you suggested, this didn't solve the problem.
With a laptop and a tablet connected to the same AP I have no lost pings.
The AP was initially configured as a RAP in bridge mode with a local breakout, but I have also tested it with a standard tunneled config.
I also have configured one of our older fat AP's from another brand, with the same ssid and in the same subnet.
With this fat AP I have no problems with the ping.

In answer to clukas:
The max power is 50mW. I played arround with it to lower it a bit, but with no result.
The distance between the PDA and my test AP is within one meter. The SNR and signal strenght are perfect.
Altough the SNR fluctuates now and then, but there seems no relation with lost pings.
I have also played arround with the roaming settings on the PDA with no result.
I disabled the higher rates, this has no result.

 

Could this be an interoperability between Summit and Aruba?
I can't find anything about it on the Aruba site.

Does any of you have suggestions ?

Aruba
Posts: 161
Registered: ‎04-03-2007

Re: lost pings with PDA's on 802.11b/g

Sounds like you have checked all the basics.

 

May I suggest you open a case with Aruba TAC?   They have a lot of experience working through interop issues with various handheld devices.  They may have a workaround for the Summits.

 

In general, Summit units are pretty old with old drivers and reduced functionality.


-cl
Occasional Contributor II
Posts: 15
Registered: ‎09-28-2010

Re: lost pings with PDA's on 802.11b/g

I will open a TAC.

 

Thanks!

New Contributor
Posts: 1
Registered: ‎10-23-2012

Re: lost pings with PDA's on 802.11b/g

Do you have any update or a solution for this problem?

Occasional Contributor II
Posts: 15
Registered: ‎09-28-2010

Re: lost pings with PDA's on 802.11b/g

Here is a final update.

 

A driver update on the PDA didn't solve the problem.

Finaly selecting " B-rates only " on the PDA did solve it.

It's a workaround, but this will do for us for this moment.

 

A

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