Low Bandwidth on intercontinental connections

[Marc Peters]

On 11/21/2012 06:52 PM, Ingo Flaschberger wrote:
> Am 21.11.2012 18:32, schrieb Marc Peters:
>> Hi Ben,
>>
>> i don't think this is memory related, too. We used plain CLI scp ot ftp
>> from base, both times.
>>
>> Here is the requested data:
>>
>> Linux ---> FreeBSD:
>>
>> root at linux:~# scp jdk-6u33-linux-x64.bin 172.16.3.10:
>> Password:
>> jdk-6u33-linux-x64.bin                             89%   61MB  59.0KB/s
>>
>> FreeBSD ---> Linux:
>>
>> [root at freebsd ~]# scp test.tgz 172.16.4.50:
>> Password:
>> test.tgz                               100%   59MB   1.1MB/s   00:55
>> [root at freebsd ~]#
>>
>>  From BSD to Linux is not as fast as L <--> L.
>>
>> I don't think, this is network related in some sort.
> 
> hm - sounds like a duplex problem?

duplex is fine (as showed by ifconfig in the first post). The switches
also show full duplex on a Gig link for this.

> 
> *) whats the distance between Linux and FreeBSD box?

some 10k kilometers. One of our DCs is in Germany, the other in the US.


> *) check network counters:
>    linux: ifconfig
>    FreeBSD: netstat -nia
>              look for errors

no errors and no collisions on any system

>    check switches between (or as far as possible) for full duplex, also
> FreeBSD (ifconfig)

the internal switches are working properly.

> *) check and compare tcpdump

for the FreeBSD hosts on the receiver side, it showed a lot of window
size changes and from time to time a lot of duplicate ACKs. i will file
a PR (as Adrian asked) and see to get a matching tcpdump and SIFTR output.

> 
> Kind regards,
>    Ingo Flaschberger
> 
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