Jelle de Jong wrote, on 15-01-10 15:20:
> James Carlson wrote, on 11-01-10 15:38:
>> Is there any chance you could make the raw tcpdump files (rather than
>> the decoded text output) available?  It's much harder to debug things
>> when information has been subtracted.
>>
>> Based on what little is available here, I'm seeing what seems to be an
>> RTT that jumps around a lot, from a few milliseconds on up to 150
>> milliseconds, and causing TCP to misbehave.  It's likely that this is a
>> kernel issue that needs to be investigated.
> 
> I created an new tcpdump of the issue and attached it in the mail.
> 
> http://filebin.ca/zmmnws/tcpdump01.tar.gz
> 
> I changed the sammy servers pppoe connection to an normal eth5
> interface to an ciso router that is providing a 50/50mbit fiber
> interface. So the upload speed of the sammy server should be very
> high. But is only 30KB when uploading to my mobile umts systems. When
> uploading form an other server to the umts systems the upload speed is
> the max of that server (100kB) so the umts systems should not be the
> problem here.
> 
> We opened the tcmpdumps with wireshark and did an analyse > export
> info and it showed a lot of "TCP Fast retransmissions" compared to the
> the other tcmpdump of the good download from the ashley server.
> 
> I also tried the below kernels, but it did not change anything.
> 
> linux-image-686 | 2.6.30
> linux-image-686 | 2.6.31
> linux-image-686 | 2.6.32
> linux-image-amd64 | 2.6.30
> linux-image-amd64 | 2.6.32
> 
> If anybody can have a look at the tcp dumps or maybe have other
> suggestion to get more debug info?

I did a lot of testing these last days, and it's making me believe the
issue is between two Dutch internet service providers (KPN <->
VODAFONE) I am still guessing how to fix it... traceroute from
Vodafone to KPN seems to go through complete Europe instead of staying
a bit local.

If somebody sees something in the tcpdumps, please enlighten me :)

Best regards,

Jelle