[Bloat] AQM creeping into L2 equipment

Toke Høiland-Jørgensen toke at toke.dk
Fri Mar 21 09:41:36 EDT 2014


Dave Taht <dave.taht at gmail.com> writes:

> I imagine with the new tcp's pfifo_fast is going to be sub 8ms also.

Yeah, turns out I botched the qdisc setup (put it on the wrong interface
on one of the servers) for the case with no switch. So the ~6ms was with
pfifo_fast in one end.

Updated the original graphs for the host-to-host. Data capture files are
here: http://kau.toke.dk/experiments/cisco-switch/packet-captures/ -- no
idea why the client seems to capture three times as many packets as the
server. None of them seem to think they've dropped any (as per tcpdump
output).

Will add dumps from going through the switch in a bit...

> Is your hardware fast enough to run tcpdump -s 128 -w whatever.cap -i
> your interface during an entire rrul test without dropping packets?
> (on client and server)

Well, as above, tcpdump doesn't say anything about dropped packets; but
since the client dump is way bigger, perhaps the server-side does anyway?

-Toke
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