Low Bandwidth on intercontinental connections

Ingo Flaschberger if at xip.at
Thu Nov 22 11:23:03 UTC 2012


>> *) 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.

*) can you check which ping-sizes work?
    ping -s 1472
    ping -D -s 1472  (should work if you have a mtu of 1500 all over the 
way)

*) any offloading/supported used at the network-card?
*) try a rate-shaping queue outgoing (not really good - as shaping works 
best on incomming interfaces):
    you need dummynet (and ipfw for this example):
   ipfw add pipe 1     all from ....
   ipfw pipe 1 config bw 10Mbit/s queue 50Kbytes
   (adjust queue size ~40ms at rated speed)

Kind regards,
    Ingo Flaschberger



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