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Re: IPv4 Address Exhaustion Effects on the Earth
From: Jim Gettys <jg () freedesktop org>
Date: Tue, 05 Apr 2011 18:07:21 -0400

On 04/05/2011 05:59 PM, Michael Proto wrote:
On Tue, Apr 5, 2011 at 5:38 PM, Jared Mauch<jared () puck nether net>  wrote:
On Apr 4, 2011, at 4:30 PM, Jim Gettys wrote:

Note that the paper "Characterizing Residential Broadband Networks" by Dischinger, et. al. indicates that a large 
fraction (in their 2 year old sample, 30% or so) of broadband head ends are running without RED, and should be doing so if at all 
possible; alternatives are years out by the time they are tested and deployed, and operators running without it in congested 
systems are inflicting pain on their customers.
Something I've observed is if you are sending data 'upstream' on the cable modem setup i have (16 down/ 2 up) and you saturate the 
upstream, the buffering destroys any downstream capability at the same time.  I'm not even sure where to start diagnosing to explaining this to the 
carrier involved, as this isn't the desired behavior of a "business class" service.

- Jared

Isn't this just a case or prioritizing outbound ACKs?

http://www.benzedrine.cx/ackpri.html


Nope. Your acks get delayed to what you are sending upstream, behind the downstream traffic.

Bufferbloat hurts both directions, once saturation occurs and your latencies start to go up.

Note that on many of these links, the RTT becomes (literally) as though you are half way (or further than) the moon.
                   - Jim




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