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l1n00xOffline
15 Post subject: [SOLVED] random wireless disconnects --> OpenWRT  PostPosted: 15.09.2010, 19:34



Joined: 2010-09-15
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I replaced my old wep-only-capable router with a new WPA2-PSK enabled one (encryption algorithm:AES). Since then I'm experiencing random disconnects.
Well, they are not so random. When downloading files to keep the network device busy I do not get any disconnects as far as I can tell. Other PCs using Windows and aptosid have not experienced these problems within the testing period which lasted several hours over several testing sessions. This leads to the conclusion that the network device might be taken into power saving mode by the kernel! As the router used a channel near to channels which were already used by other routers, I decided to switch to an unused channel. This seems to have helped, but there are still disconnects. During this time I did some downloads which could be the reason for a lack of disconnects Wink
When the pc first boots up, the transmission rate is just 1mb/s but it goes up as I browse the internet or DL sth and stays at 54mb/s. Maybe this last information is a clue to solve the problem.

I'm using the athk5 kernel modul (modprobe ath5k)

lspci:
      Code:
02:00.0 Ethernet controller: Atheros Communications Inc. AR5001 Wireless Network Adapter (rev 01)


      Code:

wpa_supplicant:
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
eapol_version=1
update_config=0
ap_scan=1
#fast_reauth=1

network={
        ssid="TP-Home"
        key_mgmt=WPA-PSK
        pairwise=CCMP
        group=CCMP
        psk="63 digits hex key"
        priority=15
        id_str="tp-home"
}


      Code:

Host/Kernel/OS  "aptosid-nc10" running Linux 2.6.35-4.slh.9-aptosid-686 i686 [ aptosid 2010-02 Κῆρες - kde-lite - (201009132215) ]
CPU Info        (1) Intel Atom N270 @ 512 KB cache flags( sse3 ht ) clocked at [ 1600.000 MHz ]
                (2) Intel Atom N270 @ 512 KB cache flags( sse3 ht ) clocked at [ 1600.000 MHz ]
Videocard       Intel Mobile 945GME Express Integrated Graphics Controller     [  ]


aptosid is fully dist-upgraded as of now!

Do you need any more information?


Last edited by l1n00x on 22.09.2010, 21:08; edited 1 time in total
 
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slhOffline
Post subject: RE: random wireless disconnects  PostPosted: 15.09.2010, 19:51



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What router are you using, because this sounds like a bug in early firmware versions found on TP-Link routers.

I can not confirm any issues with ath5k so far, using AR5001X+/ AR2414 or AR5001/ AR2425.
 
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l1n00xOffline
Post subject: RE: random wireless disconnects  PostPosted: 15.09.2010, 19:59



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Oh, its a TP-WR841N

      Code:

Firmware Version:     
3.11.3 Build 100408 Rel.42303n
Hardware Version:    
WR841N v5 00000000

There's a never HW-v7 version of this router, but I'm not aware what the differences are. SW-FW is up to date.
Strangely, disconnects only seem to happen on my ath5k wireless adapter...

I'm now running a continous ping test to confirm whether keeping the device busy will prevent disconnects from occuring.
 
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slhOffline
Post subject: RE: random wireless disconnects  PostPosted: 15.09.2010, 20:09



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Hmm, that version should be recent enough.

--
I personally prefer OpenWrt firmware on routers, which works fine on Atheros AP81/ AP83 platforms).
 
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l1n00xOffline
Post subject: RE: random wireless disconnects  PostPosted: 15.09.2010, 20:20



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But is it possible that the athk5 device could be talken into hibernation or something like that?

(OpenWrt lists the ND variant of my router which has detachable antennas. Do you know if the original FW can be flashed over OpenWrt in case I don't like it?)
 
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slamOffline
Post subject: RE: random wireless disconnects  PostPosted: 15.09.2010, 20:27
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You can always re-flash the original firmware - but I bet you will have no reason to do so.
Greetings,
Chris

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DeepDayzeOffline
Post subject: RE: random wireless disconnects  PostPosted: 15.09.2010, 20:39



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OpenWRT or Tomato should be good choices for this router. Like slh mentioned there's the possibility of firmware bugs in the stock firmware of the router that could be to blame

I have an atheros card in my thinkpad and get disconnects with ath5k as well. Ath5k is still under heavy development so there is a chance you could be experiencing bugs in ath5k too
 
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l1n00xOffline
Post subject: Re: RE: random wireless disconnects  PostPosted: 15.09.2010, 20:57



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Thanks for the help so far, but back to the topic Smile
      l1n00x wrote:
But is it possible that the athk5 device could be talken into hibernation or something like that?
 
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muchan
Post subject: RE: Re: RE: random wireless disconnects  PostPosted: 15.09.2010, 22:52
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It may be DHCP's time out. Sometimes IP address is assigned for some amount of time.
 
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l1n00xOffline
Post subject: RE: Re: RE: random wireless disconnects  PostPosted: 17.09.2010, 15:49



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No, I've mapped the IP adresses to the MACs so the lease never expires...

Just a technical question. Do you think it could be a hardware issue or is this a software problem only?
If it's a software problem then maybe using OpenWrt is an option to get rid of it!

EDIT:

Okay, I left the network idle and after a couple of minutes the network disconnected. Keeping the device busy e.g. with downloading something, it runs for hours without a single disconnect (not longer tested than 4h).

The Kernel tells me this after the disconnect:

      Code:
[  825.443570] wlan0: deauthenticated from 00:11:cd:18:32:22 (Reason: 2)
[  825.453099] cfg80211: All devices are disconnected, going to restore regulatory settings
[  825.453122] cfg80211: Restoring regulatory settings
[  825.453140] cfg80211: Calling CRDA to update world regulatory domain
[  825.469715] cfg80211: World regulatory domain updated:
[  825.469726]     (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
[  825.469736]     (2402000 KHz - 2472000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[  825.469745]     (2457000 KHz - 2482000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[  825.469754]     (2474000 KHz - 2494000 KHz @ 20000 KHz), (300 mBi, 2000 mBm)
[  825.469762]     (5170000 KHz - 5250000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[  825.469771]     (5735000 KHz - 5835000 KHz @ 40000 KHz), (300 mBi, 2000 mBm)
[  825.680866] ADDRCONF(NETDEV_UP): wlan0: link is not ready
[  861.585085] wlan0: authenticate with 00:11:cd:18:32:22 (try 1)
[  861.590662] wlan0: authenticated
[  861.590741] wlan0: associate with 00:11:cd:18:32:22 (try 1)
[  861.593007] wlan0: RX AssocResp from 00:11:cd:18:32:22 (capab=0x431 status=0 aid=1)
[  861.593064] wlan0: associated
[  861.594578] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[  872.242067] wlan0: no IPv6 routers present
 
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HeSaidOffline
Post subject: RE: Re: RE: random wireless disconnects  PostPosted: 17.09.2010, 17:19
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what is the output of
      Code:
# iwconfig

before and after the disconnect?
--
Neal

edit:
You might try
      Code:
# iwlist scan

before and after, also

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slhOffline
Post subject: RE: Re: RE: random wireless disconnects  PostPosted: 17.09.2010, 18:33



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First of all, given that installing third party firmwares (at least if you can't revert to the original firmware in case of issues) voids your warranty and isn't totally risk free, no one can "recommend" doing so with a good conscience.</disclaimer>

Personally I've seen exactly these symptoms (connections dropping on inactive links, some clients not being able to connect (ipw2200) or connecting only with desastrous performance (b43)) with a TL-WR1043ND in january, which all disappeared completely after installing OpenWrt (initially trunk + patches, now plain 10.03 backfire). A vendor firmware update in april claims to have fixed that bug (at least a friend doesn't complain anymore since upgrading to that version), but given that I intended to use OpenWrt from the beginning, the vendor firmware didn't survive more than half an hour for testing - and I never checked consecutive vendor upgrades; OpenWrt is running reliable on that hardware for ~8 months now.

(Be aware that stock OpenWrt images don't have wireless drivers preinstalled, crda, kmod-ath9k and wpad-mini need to be installed after flashing the firmware. Read generic- and router specific OpenWrt documentation before installing it. Don't attempt it, unless you're familiar with the procedure and have an emergency plan handy</disclaimer>)
 
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DeepDayzeOffline
Post subject: Re: RE: Re: RE: random wireless disconnects  PostPosted: 18.09.2010, 00:54



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      slh wrote:
First of all, given that installing third party firmwares (at least if you can't revert to the original firmware in case of issues) voids your warranty and isn't totally risk free, no one can "recommend" doing so with a good conscience.</disclaimer>

Personally I've seen exactly these symptoms (connections dropping on inactive links, some clients not being able to connect (ipw2200) or connecting only with desastrous performance (b43)) with a TL-WR1043ND in january, which all disappeared completely after installing OpenWrt (initially trunk + patches, now plain 10.03 backfire). A vendor firmware update in april claims to have fixed that bug (at least a friend doesn't complain anymore since upgrading to that version), but given that I intended to use OpenWrt from the beginning, the vendor firmware didn't survive more than half an hour for testing - and I never checked consecutive vendor upgrades; OpenWrt is running reliable on that hardware for ~8 months now.

(Be aware that stock OpenWrt images don't have wireless drivers preinstalled, crda, kmod-ath9k and wpad-mini need to be installed after flashing the firmware. Read generic- and router specific OpenWrt documentation before installing it. Don't attempt it, unless you're familiar with the procedure and have an emergency plan handy</disclaimer>)


So this is then a bug in the stock router firmware then. An alternative to OpenWRT is Tomato which is also quite reliable and has a gui for configuration. Believe this router is supported in Tomato too
 
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amdgoonOffline
Post subject: RE: Re: RE: Re: RE: random wireless disconnects  PostPosted: 21.09.2010, 09:13



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http://dd-wrt.com/wiki/index.php/Suppor ... es#TP-Link indicates dd-wrt is stable on that version of wireless router, as an option for alternative firmware.
 
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l1n00xOffline
Post subject:   PostPosted: 21.09.2010, 22:40



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I already tried OpenWRT and managed to get WPA2-PSK and the internet to work, but could not gain internet access via wireless.
I will try OpenWRT again when I have a little more spare time, though! Smile


UPDATE:
I'm trying OpenWRT now! I've used an older Image (10.3) before instead of the most recent (10.3.1-RC3), which lead to annyoing bugs. Now everything I've tested works out of the box Very Happy - No need for kmod-ath9k and wpad-mini which I had to install on 10.3. I'm now testing wireless stability. I'll keep you posted Smile
 
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