netdev - Re: [PATCH] tcp: ECN blackhole should not force quickack mode

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Message-ID: <1316999266.1865.35.camel@mojatatu>
Date:	Sun, 25 Sep 2011 21:07:46 -0400
From:	jamal <hadi@...erus.ca>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	David Miller <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>, Jerry Chu <hkchu@...gle.com>,
	Ilpo Järvinen <ilpo.jarvinen@...sinki.fi>,
	Jim Gettys <jg@...edesktop.org>,
	Dave Taht <dave.taht@...il.com>
Subject: Re: [PATCH] tcp: ECN blackhole should not force quickack mode

On Sun, 2011-09-25 at 21:24 +0200, Eric Dumazet wrote:

> 
> So we have somewhere a box that mask the TOS bits. This is a well known
> effect on some networks, unfortunately.

ok

> The 'linux funny extension' is wrong in this case, since I have no
> retransmits, no losses, yet my laptop is in quickack mode (it sends an
> ACK for every incoming data packet), because you assumed receiving a
> packet with no ECT bits means this packet was a retransmit.

No objection from me - only one corner case i can think of is if
expected behavior happens and the first data packet was a retransmit
(i.e you wouldnt have seen an ECT which you need for your heuristic),
but that is probably not a big a deal. 

In regards to the 'linux funny extension' - this was a brilliant idea
in my opinion back then from Alexey; lots of discussions happened but
I cant remember if it made it in some RFC or not (I will try to search
some old archives).

cheers,
jamal

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