a question of internet performance

Hi:
I have been evaluating red hat 9 for use in our enterprise. I have
installed it dual-boot with win2k on an hp laptop. At work where we
access the internet with dsl, my internet performance as in download
speeds and bandwith tests are on par with what I get with win2k, but at
home, where I access the internet via an smc barricade 7004br and a
dial-up modem, my internet performance is roughly half of what I get
with win2k, 25 kbps vs 46 kbps. I am a total noob with linux, and I
would really appreciate anyone's thoughts on this issue. At boot time
it shows that my ethernet adapter is connected at 100mbs full-duplex to
the barricade, and ifconfig shows this:
> eth0 Link encap:Ethernet HWaddr 00:02:3F:34:59:84
> inet addr:192.168.0.89 Bcast:192.168.3.255 Mask:255.255.255.0
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:1141 errors:0 dropped:0 overruns:0 frame:0
> TX packets:1068 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:100
> RX bytes:1128478 (1.0 Mb) TX bytes:125259 (122.3 Kb)
> Interrupt:10 Base address:0x2400 Memory:e0200000-e0200038
I have tried manually changing the mtu to 576, and that only made it worse.
Thanks for your time and consideration

On Sat, 11 Oct 2003 20:42:37 GMT, Ward Taylor <(E-Mail Removed)> wrote:
> Hi:
> I have been evaluating red hat 9 for use in our enterprise. I have
> installed it dual-boot with win2k on an hp laptop. At work where we
> access the internet with dsl, my internet performance as in download
> speeds and bandwith tests are on par with what I get with win2k, but at
> home, where I access the internet via an smc barricade 7004br and a
> dial-up modem, my internet performance is roughly half of what I get
> with win2k, 25 kbps vs 46 kbps. I am a total noob with linux, and I
> would really appreciate anyone's thoughts on this issue.

I have never noticed a difference between Win98 and Linux for ppp or
pppoe, and at dsl speeds there should be no difference for the ethernet
connection to the router. For example I have 768/128 adsl (upload sync is
actually 160) which speed tests at 645/136 (about 15% overhead is
expected), and downloads from a fast site will gradually approach 80
KB/sec. In fact I get same results from wireless laptop:

wireless-laptop WAP----Linux1----switch----Linux2-pppoe

What nic and module are you using? I have had incompatibility between PC
card nics and 7004AWBR, but that is different chip than 7004BR. I have
also experienced packet loss with a 3Com card with 3c59x module at
100baseT speed (works fine at 10baseT, and is connected to my dsl modem).

What nic and module are you using? Maybe it is not the optimum module for
the nic.

> At boot time
> it shows that my ethernet adapter is connected at 100mbs full-duplex to
> the barricade, and ifconfig shows this:
>> eth0 Link encap:Ethernet HWaddr 00:02:3F:34:59:84
>> inet addr:192.168.0.89 Bcast:192.168.3.255 Mask:255.255.255.0
>> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
>> RX packets:1141 errors:0 dropped:0 overruns:0 frame:0
>> TX packets:1068 errors:0 dropped:0 overruns:0 carrier:0
>> collisions:0 txqueuelen:100
>> RX bytes:1128478 (1.0 Mb) TX bytes:125259 (122.3 Kb)
>> Interrupt:10 Base address:0x2400 Memory:e0200000-e0200038
> I have tried manually changing the mtu to 576, and that only made it worse.
> Thanks for your time and consideration

Where did you get that idea (mtu 576 is from ancient past in a previous
century). If you are using PPPoE on your router, it likely uses default
mtu 1492 (since PPPoE has an 8-byte header), so that would likely be
optimum for your Linux nic behind the router. I have not found any lower
mtu that works any better.

--
David Efflandt - All spam ignored http://www.de-srv.com/
http://www.autox.chicago.il.us/ http://www.berniesfloral.net/
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Thank you for your comments David. I am not using pppoe however, the
barricade is connected to a us robotics 56k dial-up modem. The barricade
provides this capability via a built-in serial port. It's a simple, cheap
solution for sharing a modem on my lan. The nic in the laptop is an intel
integrated 10/100 device. I am not sure what you mean by "module" though.
Is that the driver?
Thanks

On Sun, 12 Oct 2003 12:15:25 GMT, Ward Taylor <(E-Mail Removed)> wrote:
> Thank you for your comments David. I am not using pppoe however, the
> barricade is connected to a us robotics 56k dial-up modem. The barricade
> provides this capability via a built-in serial port. It's a simple, cheap
> solution for sharing a modem on my lan. The nic in the laptop is an intel
> integrated 10/100 device. I am not sure what you mean by "module" though.
> Is that the driver?

In Linux, drivers are "modules", loaded as needed based on entries in
/etc/modules.conf and dependencies. See what 'lspci -v' shows for your
ethernet device and what 'alias eth0' shows as module used for it (which
should also show up in 'lsmod'). Note that you may have to be root (or
'su -' from a normal user) to run lspci or lsmod.

I don't really know anything about Intel nics or if all their 10/100 nics
use 'e100' module. Do you have any speed problems between LAN boxes?

One thing you might try is:

mii-tool -A 10baseT-FD,10baseT-HD eth0

I had to do that to use PC card nics on my SMC 7004AWBR due to some auto
link speed incompatibilty.

--
David Efflandt - All spam ignored http://www.de-srv.com/
http://www.autox.chicago.il.us/ http://www.berniesfloral.net/
http://cgi-help.virtualave.net/ http://hammer.prohosting.com/~cgi-wiz/

David Efflandt <(E-Mail Removed)> wrote:
> Where did you get that idea (mtu 576 is from ancient past in a
> previous century). If you are using PPPoE on your router, it likely
> uses default mtu 1492 (since PPPoE has an 8-byte header), so that
> would likely be optimum for your Linux nic behind the router. I
> have not found any lower mtu that works any better.

back in the "old days" if you had a given window size, using a smaller
MTU could make it more likely that one could generate fast retransmits
for lost segments by giving more segments per window. how SACK and
such today alter that I'm not certain.

rick jones
--
Process shall set you free from the need for rational thought.
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to raj in cup.hp.com but NOT BOTH...