Re: Linux TCP's Robustness to Multipath Packet Reordering

Eric Dumazet
2011-04-26T21:18:05Z

Le mardi 26 avril 2011 à 23:08 +0200, Eric Dumazet a écrit :
> Le mardi 26 avril 2011 à 23:04 +0200, Dominik Kaspar a écrit :
>
> > In these experiments, a queue size of 1000 packets was specified. I am
> > aware that this is typically referred to as "buffer bloat" and causes
> > the RTT and the cwnd to grow excessively. The smaller I configure the
> > queues, the more time it takes for TCP to "level up" to the aggregate
> > throughput. By keeping the queues so large, I hope to more quickly
> > identify the reason why TCP is actually able to adjust to the immense
> > multipath reordering. What parameters could be highly relevant, other
> > than the queue size?
> >
>
> losses of course ;)
>
> Real internet is full of packet losses, and probability of these losses
> depends on queue sizes (RED like AQM)
>
>

BTW, netem in linux-2.6.39 contains lot of changes in netem module

commit 661b79725fea030803a89a16cda
(netem: revised correlated loss generator)

This is a patch originated with Stefano Salsano and Fabio Ludovici.
It provides several alternative loss models for use with netem.
This patch adds two state machine based loss models.