Re: Intermittent signal problem

c.ong · ‎07-20-2004

Hi,

My floor has one AP 1200 installed. Lately, we experienced intermittent connection very often even though we were just a few metres away from the AP. I used Airmagnet to capture/decode the process that took place. This is what i have found.

AirMagnet has detected AP Audi_1st Floor (SSID:msbWL) with flawed 802.11 power-save implementation causing degraded performance for client stations. A wireless laptop station often switches the WLAN card into the 802.11 power save mode to conserve power consumption. While in power save mode, the client station relies on the AP to (1) buffer packets directed to it, and (2) notify the client station to switch out of power save mode. AirMagnet has detected that these 802.11 standards defined procedures and protocols are not being followed by the AP. In other words, AP Audi_1st Floor is either not buffering packets for power-save mode clients or not notifying them to wake up for new packets. The results are packet loss, retransmission, and wasted bandwidth. For jitter sensitive applications such as VoIP phones on WLAN, this problem impacts performance and quality of service severely. Please contact the vendor of your AP for firmware upgrade, if available, to address this client power-save mode problem.

Any idea how I can solve this?

Thanks.

Regards,

Delon

Michael Adler · ‎07-28-2004

Hi Delon,

I need more details on the client side.

Seems like the are using AP1200 in power save mode, we need to know what clients and wireless cards are being used (drivers, FW, etc) and how is the AP and the client are being configured and what OS is used. AP software config dump would also help.

Regards,

Mike Adler

c.ong · ‎07-28-2004

Hi Mike,

How to make the AP1200 to operate in power save mode? The AP is power up using an inline power switch. There are a mixture of clients used in my environment, consists of Cisco, Orinocco and 3COM. There are currently 20 of us in my floor.I might not be able to provide you all of their firmware and drivers version. Like mine is 8.3.10.0 and I'm 5 metres away from the AP. OSes such as Win 2000, Win 98 and XP are used.

I do not set up a syslog server. How can I receive the software config dump? The AP automatically rebooted itself.

Anything else that you need?

Thanks,

Delon

Michael Adler · ‎07-29-2004

Delon,

What I meant to say is that AP and the clients seem to operate in the power save mode. I am not sure how non Cisco clients operate but first I would start with Cisco clients only being connected to the AP.

I suppose you are using Cisco ACU to configure the clients cards and the profiles, if not please do so.

Then when you start the ACU on the first tab "System Parameters" please make sure you are in the CAM mode and not in Power save mode. Please observe if your performance got better; do the same with other clients.Also, I would recommend to upgrade AP to the latest software, it can be found on the URL below

http://www.cisco.com/public/sw-center/sw-wireless3.shtml

Mike.