Re: [Bloat] Random idea in reaction to all the discussion of TCPflavours - timestamps?

["Richard Scheffenegger" <rscheff@gmx.at>]

How about trying to push for a default, that the logical egress buffers are 
limited to say 90% of the physical capacity, and only ECN-enabled flows may 
use the remaining 10% when they get marked...

Someone has to set an incentive for using ECN, unfortunately...

Richard

----- Original Message ----- 
From: "Fred Baker" <fred@cisco.com>
To: "Richard Scheffenegger" <rscheff@gmx.at>
Cc: "Stephen Hemminger" <shemminger@vyatta.com>; "bloat" 
<bloat@lists.bufferbloat.net>
Sent: Thursday, March 17, 2011 1:18 PM
Subject: Re: [Bloat] Random idea in reaction to all the discussion of 
TCPflavours - timestamps?



On Mar 17, 2011, at 5:05 AM, Fred Baker wrote:

> I'm very much in favor of ECN, which in all of the tests I have done has 
> proven very effective at limiting queues to the knee. I'm also in favor of 
> delay-based TCPs like CalTech FAST and the Hamilton and CAIA models; FAST 
> tunes to having a small amount of data continuously in queue at the 
> bottleneck, and Hamilton/CAIA tunes to a small bottleneck. The problem 
> tends to be that the "TCP Mafia" - poorly named, but a smallish set of 
> people who actually control widely-used TCP implementations - tend to very 
> much believe in the loss-based model, in part because of poor performance 
> from past delay-based implementations like Vegas and in part due to IPR 
> concerns. Also, commercial interests like Google are pushing very hard for 
> fast delivery of content, which is what is behind Linux' recent change to 
> set the initial window segments.

I didn't say, and should have said: I'm also in favor of AQM in any form; I 
prefer marking to dropping, but both are signals to the end system. The 
issue is that we need the right mark/drop rate, and the algorithms are 
neither trivial nor (if the fact that after 20+ years Van and Kathy haven't 
yet published a red-lite paper they're happy with is any indication) well 
documented in the general case.=