[Cerowrt-devel] happy 4th!

Mikael Abrahamsson swmike at swm.pp.se
Sun Jul 7 20:24:25 EDT 2013

On Sun, 7 Jul 2013, dpreed at reed.com wrote:

> So when somebody "throws that in your face", just confidently use the 
> words "Bullshit, show me evidence", and ignore the ignorant person who

Oh, the people that have told me this are definitely not ignorant. Quite 
the contrary.

... and by the way, they're optimising for the case where a single TCP 
flow from a 10GE connected host is traversing a 10G based backbone, and 
they want this single TCP session to use every spare capacity the network 
has to give. Not 90% of available capcity, but 100%.

This is the kind of people that have a lot of influence and causes core 
routers to get designed with 600 ms of buffering (well, latest generation 
ones are down to 50ms buffering). We're talking billion dollar investments 
by hardware manufacturers. We're talking core routers of latest generation 
that are still being put into production as we speak.

Calling them ignorant and trying to wave them off by that kind of 
reasonsing isn't productive. Why not just implement the high RTT testing 
part and prove that you're right instead of just saying you're right?

THe bufferbloat initiative is trying to change how things are done. Burden 
of proof is here. When I participate in IETF TCP WG, they talk goodput. 
They're not talking latency and interacting well with UDP based 
interactive streams. They're optimising goodput. If we want buffers to be 
lower, we need to convince people that this doesn't hugely affect goodput.

I have not so far seen tests with FQ_CODEL with a simulated 100ms extra 
latency one-way (200ms RTT). They might be out there, but I have not seen 
them. I encourage these tests to be done.

Mikael Abrahamsson    email: swmike at swm.pp.se

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