Wireless Access


Block Ack Request

Block Ack Request
We currently have a couple of Kindle HDs and Samsung cellphone (Android Devices) that are able to associate/authenticate to our wireless network and once those associate they are able surf the internet with no issues but for some reason after 10/15 minutes both devices will loose the wifi connections even when the device shows that it is still connected on the wireless status the device is not able to obtain a connection on its on unless I perform a manual wireless off/on on the device, initially I thought that the device was going on power save mode and it was turning off the wireless card to increase performance or but it doesn't look to be the case.

To determine when the device was going off the network I had a continuous ping going to the device but then after 10/15 it will start to time out , on the controller I had the user-debug turned on for that client for didn't see anything unusual in the logs, I also was performing a wireless capture using AirMagnet and I noticed that before the device drops off you can see that association and authentication process looks normal : Beacon request , response , etc.. but once I am not able to ping the device I started seeing a bunch of Block Ack Request from the device and BSSID was it's own MAC address which looks like it was trying to act as a ADHOC device .

After that I thought that maybe the controller was classifying this traffic as a Block ACK DoS Attack but it wasn't , then I decided to bring up a test VAP\SSID profile and disabled pretty much all the features we have enabled (Band steering, Convert Broadcast ARP requests to unicast, DMO , enabled all the lower data rates, etc..) but that didn't help either.

I have taken a AirMagnet capture for different devices : iPhones, Other Android phones, Kindle Fire , Laptops, Macbooks ,etcs..And we don't see this type of behavior.

I was wondering if anybody is experiencing these type of issues .

I have attached a screenshot of the AirMagnet capture

Thank you

Victor Fabian
Lead Mobility Architect @WEI

Re: Block Ack Request

Have you tried to enable debugging for one of the problematic clients?         Can you supply the relevant log information?

Systems Engineer, Northeast USA

Re: Block Ack Request



I have attached a screenshot of the user-debug logs obtained from the controller.


Hopefully it is somewhat readable I hide a some of the stuff.





Thank you

Victor Fabian
Lead Mobility Architect @WEI
Occasional Contributor II

Re: Block Ack Request

Just curious if you were able to find a resolution to this issue.. I have been experiencing the same problem with a Linux based mobile router (InMotion Router OMM).


I have tried turning on BC/MC Optimization, increasing the "Max Transmit Failures" to 20 under the SSID settings. Also tried turning off "Detect Block ACK DoS" under IDS settings.


The device is deleted from the controller causing the connection to drop on the router device. Although the device reports that the wireless connection is fine, no traffic (ping packets in this case) are able to go through. This happens every 1 minute or so which is very disturbing for any continous wireless communication.


Here are some other posts regarding the Block ACK packets but there are no resolutions posted:










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