# [SOLVED] internet slowdown

## orkid

Hi,

My internet (DSL GMT Fast, 4032down, 768(i think) up) through a speedstream 5200 modem/router is okay at first (speeds at 417k/sec or so) and then after a while it drops to 100k/sec (hard). The router pages show ATM/AAL Rx errors at a high rate after this drop happens. It happens in Gentoo all the time, and never in other distributions (eg debian).

I think it might be something with the TCP/IP stack/settings in Gentoo. Could it have something to do with the sizing algorithms for tcp/ip on by default in gentoo kernels vs. other distributions.

Any help would be appreciated.

ps. a reboot of the modem fixes the problem temporarily (for a few minutes) before the slowdown happens again.Last edited by orkid on Sun Dec 03, 2006 7:42 am; edited 1 time in total

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## desultory

Have you tried using sys-kernel/vanilla-sources? Or any other kernel not derived from sys-kernel/gentoo-sources?

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## noddyt

Hi

I've also started having this problem in the last few days.  Ok speeds at first, then internet access speeds are terrible.

Does anyone have any solutions?

I also find a short fix for me is resetting my router, or restarting net.eth0.  Browsing to my routers internal settings is still fast, and network shares are fine, as are any downloads started before the slowdown starts, they stay fast even though everthing else is slow.

Thanks 

Noddyt

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## noddyt

Hi

After a couple of days of digging around, I've managed to fix my problem.  For some reason my kernel was compiled with IPv6 (has this been defaulted to on in the 2.6.18 kernel?) which I removed and recompiled.

I hope this fixes the problem for you as well orkid.  If it does, can you mark this topic as solved.

Thanks

Noddyt

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## orkid

it still happens for me after taking out IPV6, but my slowdowns are not the same as yours.

They unconditionally happen a few minutes after downloading at 400+K/sec. There are 'hiccups' to 350 and subsequent returns to 400+ and then a huge cut to <100K/sec. I believe that a while ago keeping the max download speeds to 400K/sec (not just maxing out the connection) would not lead to this. Could this have something to do with hardware? (asus k8v-x onboard lan using skge, SpeedStream 5200 modem in router mode)

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## noddyt

Hi

It sounds like it might be a driver error to me, so maybe try some others?

Are you using the deprecated Marvell Yukon chipset driver or the new SysKonnect GigaEthernet driver?

Also, do you have your network driver compiled into the kernel or as a module.  I seem to remember reading somewhere (and someone correct me if I'm mistaken) but building the network driver as a module can help as extra options can be passed to it as a module(what options and how though, I don't know).

Noddyt

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## orkid

i tried with skge built-in, skge as module, sk98lin as module, and it still happens. Other Linux distros work. So it's something with gentoo, or with the kernel I built.

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## orkid

This also happens with a DFE-530TX nic, via_rhine loaded as a module... and using genkernel (trying both cards). What gives?!

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## noddyt

Hi orkid

After having another dig around in the kernel, do you have 'Asynchronous Transfer Mode' selected under Networking  --->Networking options(about half way down).  Its marked experimental in my kernel(2.6.18-r2).  Maybe try switching it off if you have it on(or vise versa)?

Noddyt

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## orkid

Hi,

Thanks for all the advice. I got it fixed by running 'emerge coldplug; rc-update add coldplug boot'.

Seems like the current stable amd64 udev (87?) doesn't have coldplug builtin. I think that 103 does. Anyway, now I get to enjoy gentoo once again  :Smile: 

Don't quite know what coldplug did to fix things though. I'm using gentoo-2.6.19 with sk98lin as a module.

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## orkid

I just came across the same problem in Debian with the new udev (0.103), where coldplug is integrated into udev.

It seems like the fix is

```
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
```

This is probably the proper fix , but the 'simple hack' of installing coldplug (only for older udev versions anyway). Hopefully someone will find this useful. It seems like some hardware just doesn't like window scaling (probably the modem/router in my case, a SpeedStream 5200)

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## Waninkoko

 *orkid wrote:*   

> I just came across the same problem in Debian with the new udev (0.103), where coldplug is integrated into udev.
> 
> It seems like the fix is
> 
> ```
> ...

 

I was having the same problem with my wifi connection (ipw3945) and I resolved it with older udev+coldplug as you said. Now I'm going to test this new solution. Thanks!!

Edit: nothing  :Sad:  I'm still have slowdowns and many RX packets dropped.

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## vibrokatana

What is the connection strength like, bad wireless connections drop packets like fleas

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## Waninkoko

Around 95-99%. Now I changed the router's firmware and key encryption and I still have slowdowns. I don't want to use older udev with coldplug  :Sad: 

Edit: I have recompiled the kernel (with some options removed) and uninstalled "iptables" application. I stopped "xdm" service". I started a download with wget and it worked fine for a long time. Looks like I will find the problem very soon  :Very Happy: 

Edit 2: I HATE YOU KDEBLUETOOTH! xDD Yep, problem resolved.

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