Re: IPv4 Address Exhaustion Effects on the Earth

[Jim Gettys <jg () freedesktop org>]

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