[e2e] TCP implementations in various OS's
detlef.bosau at web.de
Wed May 12 11:55:54 PDT 2010
rick jones wrote:
> On May 12, 2010, at 2:30 AM, Detlef Bosau wrote:
> I'm arriving late to the discussion - perhaps data centers and LANs
> were not included in your set of terrestrial TCP sessions and I'm but
> providing fodder for "TCP as the one true protocol is bad" school of
> thought, but it has been my experience thusfar that over a 10 Gbit/s
> Ethernet LAN, TCP needs 128KB or more of window to achieve reasonable
Is this due to the link lenghts or due to huge interface buffers?
> Get much more than 1 ms of delay in the LAN or data center and even
> that is insufficient.
I left out the consideration, that we have to take into account the
number of active flows.
Using VJCC, any flow has a minimum window of 1 MSS. Actually, even 1 MSS
may not fit on a small link. Hence, we have to provide a certain minimum
of queueing memory to make the system work with the actual number of
flows being active.
May this be the reason for the delays you mentioned?
Actually, I don't mind reasonable window scaling when there are sound
reasons for it. Perhaps, the general term "misbehaved" is too strict and
we should better encourage a reasonable usage of window scaling.
Unfortunately, I read several discussions on this matter where window
scaling was used or encouraged quite carelessly.
> rick jones
> Wisdom teeth are impacted, people are affected by the effects of events
Lucky me, I've only two wisdom teeth left ;-)
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