You are not logged in.

#1 2009-05-14 17:35:10

robert@debian
Member
Registered: 2008-02-28
Posts: 9

iwl3945 poor performance - can't associate with AP

Hi floks,

I've very poor wlan performance under Archlinux, and just under Archlinux.
The networkmanager finds two wlan's, both have similar connection quality (approx. <25%). However, in the same
room I get a quality >85% with Windows XP or Ubuntu 9.04 (LiveCD).
A frind of mine gets >85% signal quality with his Archlinux installation. We both have Intel Corporation PRO/Wireless 3945ABG Wlan Chipset.

Therefore I asume my network config is screwed up.
I reinstalled networkmanager and network-manager-applet (0.7.1) and removed the associated wlans from the networkmanager interface to ensure that there's no bug or something like that in the current version. However, the problem with the poor recieve quality is not new to me under Arch. But it got wore in the last couple of weeks.


Dmesg output during connection attemps:

wlan0: direct probe to AP <MAC of Ap> try 1
wlan0: direct probe to AP <MAC of Ap> try 2
wlan0: direct probe to AP <MAC of Ap> try 3
wlan0: direct probe to AP <MAC of Ap> timed out
wlan0: direct probe to AP <MAC of Ap> try 1
wlan0: direct probe to AP <MAC of Ap> try 1
wlan0: direct probe to AP <MAC of Ap> try 2
wlan0: direct probe to AP <MAC of Ap> try 3
wlan0: direct probe to AP <MAC of Ap> timed out
wlan0: direct probe to AP <MAC of Ap> try 1
wlan0: direct probe to AP <MAC of Ap> try 1
wlan0 direct probe responded
wlan0: authenticate with AP <MAC of Ap>
wlan0: authenticated
wlan0: associate with AP <MAC of Ap>
wlan0: RX ReassocResp from <MAC of Ap> (capab=0x821 status=0 aid=5)
wlan0: associated
wlan0: deauthenticated (Reason: 2)
wlan0: direct probe to AP <MAC of Ap> try 1
wlan0: direct probe to AP <MAC of Ap> try 2
wlan0: direct probe to AP <MAC of Ap> try 3
wlan0: direct probe to AP <MAC of Ap> timed out
wlan0: direct probe to AP <MAC of Ap> try 1
wlan0: direct probe to AP <MAC of Ap> try 1
wlan0: direct probe to AP <MAC of Ap> try 2
wlan0: direct probe to AP <MAC of Ap> try 3
wlan0: direct probe to AP <MAC of Ap> timed out

And /var/log/messages.log says:

NetworkManager: <info>  Activation (wlan0) starting connection 'Auto foobar'
NetworkManager: <info>  (wlan0): device state change: 3 -> 4
NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) scheduled...
NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) started...
NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) scheduled...
NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) complete.
NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) starting...
NetworkManager: <info>  (wlan0): device state change: 4 -> 5
NetworkManager: <info>  Activation (wlan0/wireless): connection 'Auto foobar' requires no security.  No secrets needed.
NetworkManager: <info>  Config: added 'ssid' value 'foobar'
NetworkManager: <info>  Config: added 'scan_ssid' value '1'
NetworkManager: <info>  Config: added 'key_mgmt' value 'NONE'
NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) complete.
NetworkManager: <info>  Config: set interface ap_scan to 1
NetworkManager: <info>  (wlan0): supplicant connection state:  disconnected -> scanning
NetworkManager: <info>  (wlan0): supplicant connection state:  scanning -> associating
NetworkManager: <info>  (wlan0): supplicant connection state:  associating -> disconnected
NetworkManager: <info>  (wlan0): supplicant connection state:  disconnected -> scanning
NetworkManager: <info>  (wlan0): supplicant connection state:  scanning -> associating
NetworkManager: <info>  (wlan0): supplicant connection state:  associating -> disconnected
NetworkManager: <info>  wlan0: link timed out.
NetworkManager: <info>  (wlan0): supplicant connection state:  disconnected -> scanning
NetworkManager: <info>  (wlan0): supplicant connection state:  scanning -> associating
NetworkManager: <info>  (wlan0): supplicant connection state:  associating -> disconnected
NetworkManager: <info>  Activation (wlan0/wireless): association took too long, failing activation.
NetworkManager: <info>  (wlan0): device state change: 5 -> 9
NetworkManager: <info>  Activation (wlan0) failed for access point (foobar)
NetworkManager: <info>  Marking connection 'Auto foobar' invalid.
NetworkManager: <info>  Activation (wlan0) failed.
NetworkManager: <info>  (wlan0): device state change: 9 -> 3
NetworkManager: <info>  (wlan0): deactivating device (reason: 0).

If the wlan connection is up and running, there is no problem. But overall, it seems that under Arch I need a exellent quality to get it working.

I use fluxbox with networkmanager, gnome-power-manager and gnome-session-manager. Nothing special I guess.
Any help besides reinstalling Arch is appreciated.

Last edited by robert@debian (2009-05-14 17:37:54)

Offline

#2 2009-05-14 17:43:40

jwcxz
Member
Registered: 2008-09-23
Posts: 239
Website

Re: iwl3945 poor performance - can't associate with AP

What's the output of iwconfig?

Also, if there are multiple APs with the same ESSID, you might be connecting to the wrong one.  NetworkManager always had that problem on my system (it would connect to an AP a floor above my room versus the one right down the hall), so I switched to wicd and never looked back.

Last edited by jwcxz (2009-05-14 17:45:15)


-- jwc
http://jwcxz.com/ | blog
dotman - manage your dotfiles across multiple environments
icsy - an alarm for powernappers

Offline

#3 2009-05-15 07:37:18

robert@debian
Member
Registered: 2008-02-28
Posts: 9

Re: iwl3945 poor performance - can't associate with AP

Thanks for the hint jwcxz. There are indeed multiple APs with the same ESSID. That could be the problem, but isn't there a way to make networkmanager pick the AP with the best signal quality?
Nevertheless it's kinda wired, why does the Networkmanager from the Ubuntu LiveCD pick the right one?

Offline

#4 2009-05-15 10:32:56

MrShlee
Member
Registered: 2009-03-03
Posts: 14

Re: iwl3945 poor performance - can't associate with AP

Recent Ubuntu builds were based on a prerelease version of NetworkManager 0.7.1 while we were running the stable 0.7.0 until recently

Could you upgrade to the repo 0.7.1 release and tell me if it improves your connection. (I'm not using the latest version yet)

I've got a intel 4945 abgn and it seems to have problems picking up both of the ESSIDs on my AP - primary/guest

Offline

#5 2009-05-15 14:00:39

jwcxz
Member
Registered: 2008-09-23
Posts: 239
Website

Re: iwl3945 poor performance - can't associate with AP

I too tried to force NetworkManager to connect to certain APs over others (you can differentiate between them using the MAC address or the BSSID), but it completely failed to do so.  That's why I switched to wicd.


-- jwc
http://jwcxz.com/ | blog
dotman - manage your dotfiles across multiple environments
icsy - an alarm for powernappers

Offline

#6 2009-05-15 15:59:36

robert@debian
Member
Registered: 2008-02-28
Posts: 9

Re: iwl3945 poor performance - can't associate with AP

@MrShlee
I'm using NetworkManger 0.7.1 already. I thought updating would fix it in the first place, but it didn't help.

Well I guess I have to give wicd a try. I report back on Monday.

Offline

#7 2009-05-19 08:30:24

robert@debian
Member
Registered: 2008-02-28
Posts: 9

Re: iwl3945 poor performance - can't associate with AP

Even with wicd i get no connection. Are there any other suggestions?

Offline

#8 2009-05-19 09:11:39

EVRAMP
Member
From: Czech Republic
Registered: 2008-10-03
Posts: 173
Website

Re: iwl3945 poor performance - can't associate with AP

I also have this wi-fi card and got no problems so far. The only problem is that this card has default 1-11 channel and is not supporting 12 and 13 if not set afterwards.
What channel is your AP on?
Maybe your settings changed after update - try to use crda to find out.

Offline

#9 2009-05-22 06:22:03

robert@debian
Member
Registered: 2008-02-28
Posts: 9

Re: iwl3945 poor performance - can't associate with AP

Channel 12 and 13 are supported.

wlan0     21 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
          Channel 12 : 2.467 GHz
          Channel 13 : 2.472 GHz
          Channel 36 : 5.18 GHz
          Channel 40 : 5.2 GHz
          Channel 44 : 5.22 GHz
          Channel 48 : 5.24 GHz
          Channel 52 : 5.26 GHz
          Channel 56 : 5.28 GHz
          Channel 60 : 5.3 GHz
          Channel 64 : 5.32 GHz
          Current Frequency:2.447 GHz (Channel 8)

I'll guess it's just a problem with multible AP with the same ESSID. Well I've to use wired LAN instead then. Thank you anyway.

Offline

#10 2009-06-20 11:33:40

samhain
Member
Registered: 2007-07-19
Posts: 39

Re: iwl3945 poor performance - can't associate with AP

Hi,

I was having a very similar problem. Same network card, same driver.
I just couldn't associate with the AP unless the computer was in a 2 meter range.
Above the 2 meter range, I was getting a bunch of errors in the logs about the association attempts timing out.

I noticed that there is a parameter in the driver about the antenna. Well, my computer (a VAIO VGN-UX390N) does not have an auxiliary antenna, and the default setting for the driver is to use both the main and the auxiliary.

I changed this in /etc/modprobe.d/modprobe.conf and it worked like a charm.

options iwl3945 antenna=1

Hope this helps.


Arch is to Linux as Jeet Kune Do is to martial arts.

Offline

Board footer

Powered by FluxBB