On Mon, Jun 17, 2013 at 11:42 AM, Harshal Chhaya <harshal@xxxxxxxxx> wrote: > On an AR9342-based AP, we occasionally see the TSF timer in beacons > roll back i.e. the timer resets and starts over. This causes all > clients to disconnect probably because their power-save timers get out > of sync. This typically happens under heavy load. ... > Any ideas on what could be causing the timer to reset? What kind of > additional information would help in debugging this? Additional analysis of the packets showed that this reset at the AP was usually preceded by a flood of CRC errors i.e. it seems like a conscious decision in response to a bad channel. Can someone please verify this? Further analysis showed that these large number of CRC errors usually happened when a large number of clients (30-60) were sending uplink traffic. All the clients are either AR6102 or AR6203 devices. We are trying to adjust the CCA threshold on the clients to see if that helps reduce the CRC errors which in turn should avoid the timer reset on the AP. Are there any recommendations for what a reasonable value for the CCA threshold should be? Also, as another data-point our other AR9170-based AP doesn't reset the timer but it does hold off on transmitting beacons for several beacon intervals when these CRC errors occur. This also causes 'beacon lost' events on the clients which sometimes results in a disconnection. Thanks, - Harshal -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
