Re: [PATCH] net/ipv4, linux-2.6.30.4

[David Miller <davem@davemloft.net>]

From: Arnd Hannemann <hannemann@nets.rwth-aachen.de>
Date: Thu, 13 Aug 2009 14:40:42 +0200

> David Miller schrieb:
>> From: Daniel Slot <slot.daniel@gmail.com>
>> Date: Wed, 12 Aug 2009 20:47:44 +0200
>> 
>>> RFC 4653 specifies Non-Congestion Robustness (NCR) for TCP.
>>> In the absence of explicit congestion notification from the network, TCP
>>> uses loss as an indication of congestion.
>>> One of the ways TCP detects loss is using the arrival of three duplicate
>>> acknowledgments.
>>> However, this heuristic is not always correct,
>>> notably in the case when network paths reorder segments (for whatever
>>> reason), resulting in degraded performance.
>> 
>> Linux's TCP stack already has sophisticated reordering detection.ä
> 
> 
> Hmm, sophisticated? Sorry, it seemed pretty rudimental/random to me.

It's more sophisticated than what you're proposing, which is a hammer
which requires intervention on the part of the application.