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