A major problem with my wireless connection

[BlueDaisy]

Hello... I am using Kubuntu 11.10 on my desktop right now, after trying out many linux distributions. I do like it, but there is one big problem with my wireless connection...

Hear me out: My wireless internet connection uses a Zytel DSL modem, and a Linksys WRT54G router with WPA protection, and I'm not allowed to configure the router at all. Whenever I download anything from the internet or the software repositories, It starts downloading 1 to 3 megabytes at a normal rate of 320 kilobytes per second. After that, it stops, and the download speed falls down 1 kilobyte a second. After waiting 10 to 15 minutes, the connection downloads another 1 to 3 megabytes at a normal rate, and then falls again back down to 1 kilobyte a second. The pattern occurs over and over again, and because of this, it takes forever to download anything above 4 megabytes in size!

I am really, really desperate to get this problem fixed. It is the only reason I have to keep window on my computer, as this problem never occurs on it...

I tried a lot of things to fix it, and here is what I noticed:

- BitTorrent downloads are not affected by this problem. They all work perfectly smooth.
- When I try to configure the download mirrors in the software sources, it stalls on me, or it says something like, "couldn't find a proper mirror. please check your internet connection"
- I find this same problem in every debian-based distribution I've tried. When I tried Fedora 14 - 16, I did not have this problem, and downloads were smooth. (I had completely different problems with Fedora, which is why I don't use it...)
- I tried using the graphical tool for wpa_supplicant, but it doesn't solve the problem.
- I installed ubuntu distributions on other laptop computers in the household, and this same problem still exists.
- Even when I connected a laptop into the Linksys router, the problem remains
- When I once connect an Ubuntu computer directly into the DSL modem, all downloads were perfectly smooth without any stalling whatsoever. However, this corrupted the settings of the modem, and it took a while for my household to reconfigure it.

Please help me solve this problem, as it has been around in Debian distributions I've tried since Ubuntu 9.10. Other than this, I've experienced very little problems in Kubuntu...

[BlueDaisy]

It appears my post has been around a day, and still no response... Heres some other things:

- My internet connection uses DHCP to connect
- (a typo) when I plugged a computer into the modem, it didn't corrupt the "modem" settings. I meant to say the "router" settings. Sorry about that...
- when I used apt-get to install software, I noticed when the download speed spikes back up after only running at 1 kilobyte a second, the terminal repeats the download mirror, with a number after it.
- My desktop uses a Belkin wireless g USB adapter, while the laptops I tested had broadcom wireless cards. Not that it helps, since plugging into the router yields the same effects...

Is there any other info that I could post to help solve this problem?

[SecretCode]

You mention that it's fine if you connect directly to the DSL modem. Are you able to connect the desktop using an Ethernet cable directly into the Linksys router? One thing that may be affecting it is errors and retransmits over the wireless - in particular the max MTU size.

I thought it could be something to do with an http caching proxy on the Linksys router (which you can't change), but I can't think of any reason why that would not also affect Windows and Fedora computers.

[kc1di]

You mention that it's fine if you connect directly to the DSL modem. Are you able to connect the desktop using an Ethernet cable directly into the Linksys router? One thing that may be affecting it is errors and retransmits over the wireless - in particular the max MTU size.

I thought it could be something to do with an http caching proxy on the Linksys router (which you can't change), but I can't think of any reason why that would not also affect Windows and Fedora computers.

I Believe SecretCode may have hit the problem when he questions the MTU setting you can check the setting by right clicking on the Network Manager in the panel. go to net work manager settings >wireless <your connection name> click edit at the bottom of the next pane you should see your MTU setting default is usuall automatic. Check and see what it's set for.

[SecretCode]

The command

ping your.router.ip -c 1 -M do -s 1472

can help check what the MTU should be set to - vary the size value until it reports an error

And/or just set it to 1200 or something and see if that bypasses the problem

[BlueDaisy]

Yes, when I connected my computer into the wireless router, I did use an ethernet cable. This problem in my post remained.

When I used the command:

'ping your.router.ip -c 1 -M do -s 1472' (replacing the number '1472' with 600 from 2000, in 100 increments)

this was the output:

bluedaisy@WW:~$ ping linksys_SYS_31576.ip -c 1 -M do -s 600
PING linksys_SYS_31576.ip (92.242.140.1) 600(628) bytes of data.

--- linksys_SYS_31576.ip ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

bluedaisy@WW:~$ ping linksys_SYS_31576.ip -c 1 -M do -s 2000
PING linksys_SYS_31576.ip (92.242.140.1) 2000(2028) bytes of data.
From WW.local (192.168.1.104) icmp_seq=1 Frag needed and DF set (mtu = 1450)

--- linksys_SYS_31576.ip ping statistics ---
0 packets transmitted, 0 received, +1 errors


If so, I'm guessing the MTU setting is 1450 on my connection.

When I checked network manager, MTU was at automatic settings. I decided to replace it with 1450, and reconnected. Unfortunately I found that my same problem occured again.

Anything else I can do?

[SecretCode]

So the problem is not specific to wireless, then ...

Does seem odd.

Try downloading something at the command line to rule out browser issues. Pick a file of 10MB or so and use wget to download it, and see if the download speed shows the same problem.

[BlueDaisy]

I did this... The problem remained, similar to most downloads of flash, firefox downloads, and apt-get. Here's What the comand line shows:

bluedaisy@WW:~$ wget http://sourceforge.net/projects/synf...6.deb/download
--2012-01-29 11:55:10-- http://sourceforge.net/projects/synf...6.deb/download
Resolving sourceforge.net... 216.34.181.60
Connecting to sourceforge.net|216.34.181.60|:80... connected.
HTTP request sent, awaiting response... 302 Found
Location: http://downloads.sourceforge.net/pro...se_mirror=iweb [following]
--2012-01-29 11:55:13-- http://downloads.sourceforge.net/pro...se_mirror=iweb
Resolving downloads.sourceforge.net... 216.34.181.59
Connecting to downloads.sourceforge.net|216.34.181.59|:80... connected.
HTTP request sent, awaiting response... 302 Found
Location: http://iweb.dl.sourceforge.net/proje...ter.8_i386.deb [following]
--2012-01-29 11:55:14-- http://iweb.dl.sourceforge.net/proje...ter.8_i386.deb
Resolving iweb.dl.sourceforge.net... 70.38.0.134, 2607:f748:10:12::5f:2
Connecting to iweb.dl.sourceforge.net|70.38.0.134|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 21366436 (20M) [application/x-debian-package]
Saving to: `download'

9% [===> ] 2,001,669 234K/s in 45s

2012-01-29 11:56:05 (43.2 KB/s) - Connection closed at byte 2001669. Retrying.

--2012-01-29 11:56:06-- (try: 2) http://iweb.dl.sourceforge.net/proje...ter.8_i386.deb
Connecting to iweb.dl.sourceforge.net|70.38.0.134|:80... connected.
HTTP request sent, awaiting response... 206 Partial Content
Length: 21366436 (20M), 19364767 (18M) remaining [application/x-debian-package]
Saving to: `download'

20% [++++====> ] 4,414,289 26.5K/s in 97s

2012-01-29 11:57:43 (24.4 KB/s) - Connection closed at byte 4414289. Retrying.

--2012-01-29 11:57:45-- (try: 3) http://iweb.dl.sourceforge.net/proje...ter.8_i386.deb
Connecting to iweb.dl.sourceforge.net|70.38.0.134|:80... connected.
HTTP request sent, awaiting response... 206 Partial Content
Length: 21366436 (20M), 16952147 (16M) remaining [application/x-debian-package]
Saving to: `download'

41% [+++++++++=========> ] 8,911,327 27.8K/s in 14m 43s

2012-01-29 12:12:28 (4.97 KB/s) - Connection closed at byte 8911327. Retrying.

I did take a screen with the command line and system monitor, but i had problem uploading it. Wget is still downloading as we speak...

[SecretCode]

Although not wireless-specific it still sounds like something to do with errors (and retransmissions). What is the output of

ifconfig -a
iwconfig

(put your output between [ code ][/ code ] tags for better readability)

[BlueDaisy]

Here is what comes out:

bluedaisy@WW:~$ ifconfig -a
eth0      Link encap:Ethernet  HWaddr 00:21:70:02:23:b7  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:42 Base address:0x6000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:219 errors:0 dropped:0 overruns:0 frame:0
          TX packets:219 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:13620 (13.6 KB)  TX bytes:13620 (13.6 KB)

wlan0     Link encap:Ethernet  HWaddr 00:1c:df:a1:08:0a  
          inet addr:192.168.1.104  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1450  Metric:1
          RX packets:76526 errors:0 dropped:0 overruns:0 frame:0
          TX packets:50087 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:94361012 (94.3 MB)  TX bytes:6366897 (6.3 MB)

bluedaisy@WW:~$ iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

wlan0     IEEE 802.11bg  ESSID:"linksys_SES_31576"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:14:BF:A3:80:1A   
          Bit Rate=54 Mb/s   Tx-Power=20 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=34/70  Signal level=-76 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:672   Missed beacon:0

[SecretCode]

Sadly () no errors visible there. It must be something at the session level ... and I'm not sure what to look at next ...

[BlueDaisy]

I see... This must be quite a mind boggling case. Should you know, the wget download was successful, although it took more than an hour to do.

However, I really want it fixed... Do you know anyone in this forum, or in the ubuntu forums that might have more knowledge of internet problems? As my original post said, I've had this problem since I originally tried ubuntu 9.10, so there might be someone who might have solved this problem. Also, the WRT54G linksys router I'm forced to use is at least 6 years old, so don't see how it would be too new to use...

[SecretCode]

I'm sure there are people here who've dealt with issues like this - in fact, I've dealt with issues like this (data networking used to be my specialist area) but not with general Linux distros and only in a corporate network. My next thought is it could be something to do with TCP/IP receive window sizes - but I have no idea what tools to use to investigate it.

If you get no answers in a day or so, post a new thread titled something like "Network download performance issues with Ubuntu" or something, in case some people are not paying attention to this thread. And it that also doesn't get any responses, yes try another forum - I find linuxquestions.org to be one of the better forums.

Meanwhile, calling other forum members for input!

[Snowhog]

Hello... I am using Kubuntu 11.10 on my desktop right now, after trying out many linux distributions. I do like it, but there is one big problem with my wireless connection...

Hear me out: My wireless internet connection uses a Zytel DSL modem, and a Linksys WRT54G router with WPA protection, and I'm not allowed to configure the router at all.

That concerns me. Why are you not able to configure the router? Is it not yours? If not, who is the administrator for it?

[BlueDaisy]

Thank you for all of your help. Don't worry - I'll be patient!