Extremely slow internet using wifi.

Question

Hi guys,
First post here so be gentle.
After a week or so of using Arch I started noticing some strange things happening so far:
- Pacman's package list downloading from the repos happens at regular speed (around 700Kb/s), then followed by a 30 secs lag between each package download, which starts at normal speed, but then come down to around 2Kb/s then I get an Address Record error, which terminates the download.
- first ping to google is fine, then any ping after either get a 'host unknown' error or ping takes around 9Kms.
- another strange behavior that happens when pinging is that the wireless connection start at a bit-rate of 1Mb/s (according to iwconfig), then every time I ping google the bit-rate jumps (1Mb/s -> 12Mb/s -> 24Mb/s -> 54Mb/s -> 81Mb/s).
- can't load any websites (google takes around 5min to load, most other sites I just get a timed out error)
So my config is as follows:
- Intel Centerino Ultimate-N 6300
- connected using NetworkManager (but while connected with wicd the problem still occurs).
- running gnome 3.
- the router is Edimax 6524n
So far, I've checked resovle.conf (which only states my router ip address, which is fine because it serves as my DNS server), my hosts file (which is configured according to the tutorial in ArchWiki) and I've disabled the ipv6 module.
I've asked in several forums so far but with not much success, so i'm really hoping someone can solve it for me.
Thanks in advance!
PS: in one of the forums i asked someone asked me to post the output of dmesg | grep -i iwlagn, so here it is:
pastebin.com/Pmhi6swv
PS2: This problem does not occur in any of the Windows machines that are connected to the wireless network nor does it happen when this exact machine runs Windows; so the problem is definitely in Linux
Last edited by gzaidman (2011-06-01 20:18:37)

Answer 1

I'm kind of having a similar problem. Ever since upgrading to 2.6.39 my wifi is extremely slow. It connects in g mode according to iwconfig and other network analyzing programs. I have iwl3945. The problem is. First it connects to wifi network(which takes about 30secs to successfully complete a connection request) it works great and I'm measuring 25Mbit(which is my internet connection speed) on speedtest.net. But after some minutes my speed drops to around 100KB/s and has a slight fluctuation, not quite constant. Even the upload is bigger than the download speed. If I disconnect the wifi, reload the kernel module and reconnect, then it works again for 1-2 minutes at full speed, then the speed drops again.
http://www.speedtest.net/result/1338532978.png
Any suggestions, or ideas would be very helpful. Thank you.
btw. I use NetworkManager and kernel 2.6.39
iwconfig output:
wlan0     IEEE 802.11abg  ESSID:"Kozma2" 
          Mode:Managed  Frequency:2.442 GHz  Access Point: 00:23:54:14:CE:E6   
          Bit Rate=54 Mb/s   Tx-Power=15 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=50/70  Signal level=-60 dBm 
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:37462   Missed beacon:0