Hello, we have observed unusually long delays over the wireless 802.11 link AFTER the link is subjected to 2mbps bandwidth streaming with degraded signal conditions. We observe between 2 to 5 seconds delay, verified through ping, after going through a network degradation event, where as, before the event, pings show between 2ms to 20ms delays. It is believed that some dynamic queuing is going on either in the socket level, the MAC80211, or the Ath9K driver level. The ping delay may drop down to the 2-5ms delay after hours of idle state operation. Any guidance would be appreciated.

Setup and creation of observation.
1. OpenEmbedded Poky uname -r gives: 3.0.35-4.4.0
2. lspci shows Atheros, AR928X Wireless Network
3. One ap running hostap, one client setup, no encryption, fixed ip, fixed channel, close range 10 feet.
4. key wireless configuration setup
Client side ----------------
auto wlan0, static IP
wireless_mode managed
wpa-driver wext
wpa-conf /etc/wpa_supplicant.conf >>> etc ...
wpa_supplicant.conf: key_mgmt=NONE
AP side --------------------
hostapd.conf:
interface=wlan0
ssid=snbc1
channel=7
no "auto wlan0", static ip, no wireless mode management
5.after power cycle system, launch ap and client
6. iwconfig wlan0 show 11mbps, link 70/70, -11dbm, excessive retry=0
6. ping to observe 2-20ms delay
7. run video at 2mbps, with ping continuing at 2-20ms delay
8. shield ap side and observe packet loss through rtp sequence number tracking test code
9. remove shield from ap to observe no errors and solid streaming of video.
10. ping now shows up to 5 seconds delay.
11. disable video streaming completely.
12. Ping continues to show upto 5 seconds delay.
13. Over different trials, the final ping delay range from 500 ms to 5 seconds. Per trial, the delay between pings are consistant with about 20% variation.

I do hope there is enough information here to show that the tests were carried out with good integrity, and that it was not accidental configuration that resulted in this. We have re-imaged both the ap and the client side multiple times to insure release level configuration, but have not seen any difference in performance.