Wireless Access

Hi at all,

since we use Aruba (7220 Controller, AP-315) we noticed some trouble with clients.

 

It seems that when a client dissconnects (ie. for roaming) there is sometimes no reconnect. There are no hints in the logs. We have to restart the clients to force a reconnect.

 

Is there any setting that prevent clients to reconnect? We noticed that the client does roaming very often. Is it possible that there is a setting (counter etc.) which prevents a client to reconnect after hundreds of roaming events in a short time period?

 

What we noticed are a lot of "Unspecified Failure" when looking over "show ap client trail-info".

 

Thanks for every advice

You don't give us enough information to go on.

 

I would turn on user debugging and see in detail what is possibly wrong with the client.

 

If your client roams too much, that means that the transmit power on your access points is too great.

 

If you accidentally put a "user any service dhcp permit" is your user role acl, replace that with "any any serice dhcp permit", because that can delay a client reconnecting from getting an ip address.

 

You need to make sure your dhcp lease time is longer than the user idle timeout, because that can delay a reconnecting client.

 

I am out of guesses about what could be wrong.

The “any any serice dhcp permit” is a good point to check, i focus this problem a couple of weeks ago with reconnecting clients issues. Clients dont get dhcp by reconnecting. I work on this with tac support for 3 hours before we solved the issue. End the end “my fault” :) So indeed a good point to check first.

Also check that you disable the lower data and transmit rates under 12mbit for roaming optimasation (note, it will also disable very old clients using 802.11b)

Thanks,

 

The Transmit Power (802.11a) ist set to:

min 12

max 18

default. 

The AP's in that area automatically choose 18.

 

The clients don't use dhcp. They are with fixed IP's

 

Is it posssible to do a decrypt packet capture to check what is happening in the air? I found an option to capture the managment traffic and send it to wireshark. But I need to see what is "inside"...

I would open a tac case in parallel to this, because they would have access to alot of information that we will not here.  We are just guessing based on the limited information you are giving us.

Also, show auth-tracebuf mac <mac's client address> will show the back and forth management frames for that client, IF management traffic is the issue.