[AusNOG] ADSL2+ line sync data

[Joshua D'Alton]

Yea perhaps I should have said "isn't as applicable for home connections".
All your rebuttal points I agree with completely, I guess the point I was
making was, that in terms of "raises a set of TCP performance issues", --->
it does, but when it comes to home xDSL FTTx that the theory might not be
as relevant when it comes to the actual reality of the user use cases.

As in "Sad thing about this is that doing that appears to be a good idea,
but that actual best thing for performance is symmetry", true in theory and
some realities, but in home connectivity reality 18/1 will beat 11/11 the
vast majority of the time and therefore the users will pick that the
majority of the time. The cases where they don't being the cases they
actually need sufficient upload to negate the small difference in download
potential.

Anyway, interesting subject I'll take my foot out of my mouth now!


On Sat, Sep 14, 2013 at 11:31 AM, Mark ZZZ Smith
<markzzzsmith at yahoo.com.au>wrote:

>
>
>
>
> ----- Original Message -----
> > From: Mark ZZZ Smith <markzzzsmith at yahoo.com.au>
> > To: Joshua D'Alton <joshua at railgun.com.au>
> > Cc: "ausnog at lists.ausnog.net" <ausnog at lists.ausnog.net>
> > Sent: Saturday, 14 September 2013 10:15 AM
> > Subject: Re: [AusNOG] ADSL2+ line sync data
> >
> >
> >
> >> ________________________________
> >>  From: Joshua D'Alton <joshua at railgun.com.au>
> >> To:
> >> Cc: "ausnog at lists.ausnog.net" <ausnog at lists.ausnog.net>
> >> Sent: Friday, 13 September 2013 10:25 PM
> >> Subject: Re: [AusNOG] ADSL2+ line sync data
> >>
> >>
> >>
> <snip>
> >
> > Symmetry doesn't eliminate congestion (nothing does),
>
> And to clarify what I mean by this, TCP attempts to push the network into
> congestion to measure and then maximise the use of the available capacity
> between the end points. When packets are lost, TCP considers that to be a
> sign of congestion and backs off its send rate.
>
>
> > but it can provide
> > equal performance and quality in both directions for TCP and other
> protocols and
> > applications. Video can be the same quality in both directions, not
> better in
> > one direction than the other (asymmetry of bandwidth is going to put a
> real
> > cramp on telemedicine, as the patient will see the doctor really well,
> but the
> > doctor won't see the patient really well - and doctors won't accept that
> > because their malpractice premiums would then go up). Uploads will have
> as much
> > congestion effect as downloads.
> >
> >>
> >> I don't know exactly what ratio is 'ideal',
> >
> > True, but the IETF do, and they're the experts on Internet protocols.
> They
> > designed TCP, and they've published an RFC that has become a Best Common
> > Practice on how asymmetry impacts its performance.
> >
> > If you read nothing else, read the following from the summary,
> >
> > "Asymmetry, and particular high asymmetry, raises a set of TCP
> performance
> > issues."
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ausnog.net/pipermail/ausnog/attachments/20130914/c4b086cc/attachment.html>