My Internet connection (ADSL) dies under load

Hi,

At home, I've recycled my old Pentium 150 Mhz into a router in order
to share my Internet Connection between all my computers. It's working
fine for "normal" web access such as mail reading, web browsing, ...
However my connection seems to dye as soon as there is some load, for
example a P2P client (emule) or
the HTTP download of a Linux ISO.
Everything works fine for a while (for ex, 250 MB on the ISO at 250
Kbits per second) and then there seems to be no more answer from the
internet : in this case, the only solution is to log on the linux box,
do a "ifconfig eth1 down" followed by request for a "udhcpc -i eth1"
and the connection is back ...

I've tried everything I could think of and have no more track. If
someone has an idea or even better a solution ;-) please let me know.

My Linux Router hardware configuration is the following :
- Pentium 150 Mhz / 48 Mb of RAM
- Sagem F@st 800 Modem (usb) on a DSL connection 2400 DL / 384 UL
- NEC USB Controller
- Realtek 8139
- one floppy drive

My software configuration is :
- Linux kernel 2.4.24
- Eagle driver 1.9.4 (modem)
- Busybox 1.00 pre 7
- Uclibc 0.9.24
- iptables 1.2.9

Everything fits on a single floppy which allows me to get rid of my
noisy hard disk.

Unfortunately, the system logs are completely empty.
I've been trying without much success wondershaper & dsl_qos_queue.

Thanks in advance for any help.
Regards,
TooToon.

> At home, I've recycled my old Pentium 150 Mhz into a router in order
> to share my Internet Connection between all my computers. It's working
> fine for "normal" web access such as mail reading, web browsing, ...
> However my connection seems to dye as soon as there is some load, for
> example a P2P client (emule) or
> the HTTP download of a Linux ISO.

A few possibilities stand out to me:

1) ADSL stuffs data over the phone lines by utilizing non-voice bands
within your phone line's frequency range. When there's more data flowing,
a larger portion of the total phone line bandwidth is used for data, and
it crowds the voice band. There is a risk of the voice interfering with
the data. You might want to try adding an extra ADSL filter to your other
phones. However this all only makes sense if your connection drops around
when the phone line is in use for voice calls.

> - Sagem F@st 800 Modem (usb) on a DSL connection 2400 DL / 384 UL

2) Are you using the appropriate ADSL modem for your ISP? There are
various high-speed models, some which are set to use a higher data
bandwidth than the ISP wants you to use. They can cutoff the connection
if it exceeds their predefined subscriber rate. Your 2.4 Mbps downstream
is huge... are you actually paying for that?

3) Variation of the above, it could simply be that the clarity of audio
signal required to sustain such a large data bandwidth (into the Mbps) is
unattainable given your telephone lines and physical distance from your
ISP. In such a case you will have better results by using a slower modem,
or maybe there's software that allows you to configure the modem?

4) The ISP could be cutting off people who transfer too much data -- e.g.
punitive for file swapping but I kind of doubt this is your case because
it happens even when you're downloading. Typically this form of ISP's
sense of morality is enforced when you're uploading.

--
Jem Berkes
http://www.sysdesign.ca/

"Jem Berkes" <jb@users.pc9.org> wrote in message
news:Xns94915B095DB30jbuserspc9org@130.179.16.24.. .
> > At home, I've recycled my old Pentium 150 Mhz into a router in order
> > to share my Internet Connection between all my computers. It's working
> > fine for "normal" web access such as mail reading, web browsing, ...
> > However my connection seems to dye as soon as there is some load, for
> > example a P2P client (emule) or
> > the HTTP download of a Linux ISO.
>
> A few possibilities stand out to me:
>
> 1) ADSL stuffs data over the phone lines by utilizing non-voice bands
> within your phone line's frequency range. When there's more data flowing,
> a larger portion of the total phone line bandwidth is used for data, and
> it crowds the voice band. There is a risk of the voice interfering with
> the data. You might want to try adding an extra ADSL filter to your other
> phones. However this all only makes sense if your connection drops around
> when the phone line is in use for voice calls.

It would be more likely that interference with high frequencies on the phone
line interferes with high data rates. Voice is at the bottom end. There
may be too much attenuation at the high end. Possibly too far from the
exchange. Try asking the ISP to set a lower maximum data rate.

> > - Sagem F@st 800 Modem (usb) on a DSL connection 2400 DL / 384 UL
>
> 2) Are you using the appropriate ADSL modem for your ISP? There are
> various high-speed models, some which are set to use a higher data
> bandwidth than the ISP wants you to use. They can cutoff the connection
> if it exceeds their predefined subscriber rate. Your 2.4 Mbps downstream
> is huge... are you actually paying for that?

I thought the modems autonegotiated maximum speed and the ISP set the
maximum for the modem at the exchange.

> 3) Variation of the above, it could simply be that the clarity of audio
> signal required to sustain such a large data bandwidth (into the Mbps) is
> unattainable given your telephone lines and physical distance from your
> ISP. In such a case you will have better results by using a slower modem,
> or maybe there's software that allows you to configure the modem?

Yes - but you don't mean audio clarily but frequencies way above audio.

> 4) The ISP could be cutting off people who transfer too much data -- e.g.
> punitive for file swapping but I kind of doubt this is your case because
> it happens even when you're downloading. Typically this form of ISP's
> sense of morality is enforced when you're uploading.

There could also be intermittent fauls on the line with (moist) dirt or
contaminants coming across the wires. If the impedance was right this would
affect higher frequencies but may not be noticable of voice. There could
also be terminations not done correctly having the same result.

> --
> Jem Berkes
> http://www.sysdesign.ca/

On Mon, 16 Feb 2004 02:25:41 -0800, tootoon92 wrote:

> Hi,
>
> At home, I've recycled my old Pentium 150 Mhz into a router in order
> to share my Internet Connection between all my computers. It's working
> fine for "normal" web access such as mail reading, web browsing, ...
> However my connection seems to dye as soon as there is some load, for
> example a P2P client (emule) or
> the HTTP download of a Linux ISO.
> Everything works fine for a while (for ex, 250 MB on the ISO at 250
> Kbits per second) and then there seems to be no more answer from the
> internet : in this case, the only solution is to log on the linux box,
> do a "ifconfig eth1 down" followed by request for a "udhcpc -i eth1"
> and the connection is back ...
>
> I've tried everything I could think of and have no more track. If
> someone has an idea or even better a solution ;-) please let me know.
>
> My Linux Router hardware configuration is the following :
> - Pentium 150 Mhz / 48 Mb of RAM
> - Sagem F@st 800 Modem (usb) on a DSL connection 2400 DL / 384 UL
> - NEC USB Controller
> - Realtek 8139
> - one floppy drive
>
> My software configuration is :
> - Linux kernel 2.4.24
> - Eagle driver 1.9.4 (modem)
> - Busybox 1.00 pre 7
> - Uclibc 0.9.24
> - iptables 1.2.9
>
> Everything fits on a single floppy which allows me to get rid of my
> noisy hard disk.
>
> Unfortunately, the system logs are completely empty.
> I've been trying without much success wondershaper & dsl_qos_queue.
>
> Thanks in advance for any help.
> Regards,
> TooToon.


Check if the 8139 NIC is faulty by transfering data between it and another
computer.


Try to replace the USB with an ethernet modem and see if it solves
problem.