misc/140346: High bandwidth use causes loss of wlan connection

Daniel Casner dc at anybots.com
Fri Nov 6 20:00:05 UTC 2009

>Number:         140346
>Category:       misc
>Synopsis:       High bandwidth use causes loss of wlan connection
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Nov 06 20:00:04 UTC 2009
>Originator:     Daniel Casner
>Release:        8.0-BETA3
Anybots Inc.
8.0-BETA3 FreeBSD 8.0-BETA3 #1: Mon Aug 31 08:58:35 PDT 2009     root at plutonium:/usr/obj/usr/src.RELENG_8/sys/GENERIC  i386
I am using a rum wireless card (Asus WL-167g) wireless card and creating a wlan virtual device from it to connect to a wireless network. This same card worked flawlessly under FreeBSD 7.

The interface associates with wireless networks just fine, however, any time I try to push a large amount of data over the interface, such as writing a 100Mb file over NFS, the connection will die and not be restored.

Setting "wlandebug state+scan" it appears that the wlan device is performing background scans and re-associating correctly, however, the operating system does not resume sending packets over the interface. I can not ping from the wireless device or ping it from the out side after the connection dies.
Set up a wireless connection, here is an example from my rc.conf

ifconfig_wlan0="ssid Anybots netmask"

Mount an NFS partition, write a large file over NFS.

The connection is usually lost fairly quickly.


ifconfig wlan0 down
ifconfig wlan0 up scan

Usually restores the connection, however, continuing to try and push a large amount of bandwidth will cause it to die again.


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