[Bloat] when does the CoDel part of fq_codel help in the real world?

[Dave Taht]

On Thu, Nov 29, 2018 at 9:51 PM Mikael Abrahamsson <swmike at swm.pp.se> wrote:
>
> On Thu, 29 Nov 2018, Stephen Hemminger wrote:
>
> > The problem is that any protocol is mostly blind to the underlying
> > network (and that can change).  To use dave's analogy it is like being
> > put in the driver seat of a vehicle blind folded.  When you step on the
> > gas you don't know if it is a dragster, jet fighter, or a soviet
> > tractor. The only way a protocol can tell is based on the perceived
> > inertia and when it runs into things...
>
> Actually, I've made the argument to IETF TCPM that this is not true. You
> can be able to communicate earlier data from previous flows on the same
> connection so that new flows can re-learn this.
>
> If no flow the past hour has been able to run faster than 1 megabit/s and
> always PMTUD to 1460 bytes MTU outbound, then there is good chance that
> the next flow will encounter the same thing. Why not use this information
> when guessing how things will behave going forward?

I've actually assumed that the insanely big providers actually did
this, that they did a lookup on connect into BGP ASN database (aha!
this address is 4G, This is DSL, This may be wifi, this one is weird).
Keeping a few bits of state around awhile for every ipv4 address in
the world today is trivial with today's technologies.

>
> --
> Mikael Abrahamsson    email: swmike at swm.pp.se
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-- 

Dave Täht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-831-205-9740