[strongSwan] Big packet loss under load

Roland Mas lolando at debian.org
Thu May 15 18:00:11 CEST 2014

Roland Mas, 2014-05-15 17:13:11 +0200 :


>> When using netcat with TCP, flow control takes care that packet loss
>> is minimal. You may try to switch to iperf with some larger UDP
>> bandwidths to check if you can reproduce these losses. Also, if you
>> have a few hundred sockets some special Netfiltering/Conntracking may
>> slow things down compared to a single TCP stream?
>   I'll investigate these points, and report back if I find anything
> significant.

  Using iperf in UDP, I get <0.01% packet loss until 200 Mb/s, then it
increases to 1-10% (varying across runs) at 300 Mb/s.  However, this
seems to have no impact on a ping running in parallel.

  Nothing significant in the kernel logs, and there don't seem to be
anything about conntracking in the netfilters.  nf_conntrack_max is set
at its default value (65536), so we should be fine from that

  Any other hint?

Roland Mas

Le weblog entièrement nu -- http://roland.entierement.nu/
Le photoblog entièrement net -- http://roland.entierement.net/

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