Clients dropping from wireless APs

[larbakium]

I am using 4 Cisco APs, connected together by Wireless Controller, to a router which then connects to the broadband modem.

The users, use Win7 laptops to connect to the wireless network. Than they connect to a VPN client and stay connected all day. Not all users use the same VPN client, therefore more than 1 VPN client type is displaying the problem.

PROBLEM:

The users complain they loose connection very often. They know it because the VPN client drops connection and attempts to reconnect. This happens with all users at different times of the day.

Troubleshooting:

Looks for logs on the pcs in order to find if the problem was with the VPN client or the OS dropping connection. No errors display on the VPN client neither on the wlan log (which displays connection was terminated and restarted several times but not mentioning a specific error).

Then I though it could be security level on the APs. I have disabled authentication. Problem continues. I have removed MAC filtering, make the network completely open and unsecured. Problem continues.

Then I wanted to eliminate the problem could be on the broadband line. So I connected one laptop wired to the router. NO problems occur. No drops.

This leads me to think the problem is around the APs... since security is down and problem still occur..

what else should I be looking at here?

thank you

[Yahya Jaber]

Hi,

first, let us check the timers that are configured on your WLC and WLAN.

check the idle timeout on the Controller Tab.

and the session timeout on the WLAN advanced tab.

if the issue presists, go to the WLC CLI, and issue debug client and re-produce the issue, from there we can try and see what is happening.

[larbakium]

Hi Yahya Jaber,

Values are per default...

User Idle Timeout (seconds) > 300

ARP Timeout (seconds) > 300

Coverage Hole Detection > Enabled

Enable Session Timeout > 1800

Client Exclusion > enabled with Timeout Value (secs) > 60

I am new using the controller. I did find doc.. but the MAC when I am running the debug is the client laptop or the AP the laptop is connected to to? If its the AP, I use the Base Radio MAC or the Ethernet MAC?

Thanks

[Amjad Abdullah]

Rui:

Disconnection on the VPN client does not mean the wireless connection was terminated. The VPN connection can go down without the wireless connection goes down (on layer 2). So, just make sure that the wireless connection is really being lost when the problem happens. If the wireless connection is UP but only the VPN goes DOWN then you have to check the VPN link before checking the wireless side.

Now, If you sure that the wireless connection goes DOWN and you can see the wireless indicator on the OS get disconnectied, you need to know the reason of that disconnection.

Yahya above mentioned two things that you may check:

- session timeout: this is configurable under WLAN. default is 30 minutes (1800 s). So, every 30 minutes - by default - the users will get disconnected and get connected again. You  may disable this timer or increase it to a higher value.

- user idle-timeout: this is configurable under controller tab.

If you eliminate the above timers and you still have issues please let us know so we proceed with troubleshooting.

Regards,

Amjad

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[larbakium]

Amjad,

I have see in 2 cases where the wifi gauge indicated disconnected. Also the Event viewer (WLAN adaptor) on the OS tells me the connection was closed. But not why it was closed.

Also, when users are connected wired this does not happen.. which helps rulling out the VPN client communication link.

I have removed the Enable Session timeout and Client Exclusion (even if Im not sure about this setting...).

I will keep it for 2 days.. be back on friday.

[Scott Fella]

Disable the session timeout in the WLAN advanced tab and set the idle timeout to 7200 and let that run for a while and see.

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