From: Ingemar Johansson S <ingemar.s.johansson@ericsson.com>
To: Mirja Kuehlewind <mirja.kuehlewind@ikr.uni-stuttgart.de>,
 "conex@ietf.org" <conex@ietf.org>
Date: Tue, 15 Nov 2011 09:25:57 +0100
Thread-Topic: [conex] ConEx as sender side only modification
Thread-Index: Acyi7G1lvsYaNDVfT3ugbT7K+KHp6wAgr58g
Message-ID: <DBB1DC060375D147AC43F310AD987DCC42D7A89A6F@ESESSCMS0366.eemea.ericsson.se>
References: <20111030141755.21962.83789.idtracker@ietfa.amsl.com>
 <20111107160135.GA45061@verdi>
 <DBB1DC060375D147AC43F310AD987DCC42D7A26772@ESESSCMS0366.eemea.ericsson.se>
 <201111141742.38336.mirja.kuehlewind@ikr.uni-stuttgart.de>
In-Reply-To: <201111141742.38336.mirja.kuehlewind@ikr.uni-stuttgart.de>
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Subject: Re: [conex] ConEx as sender side only modification
Precedence: list

Thanks

This then means that a policer need to give some extra slack for normal TCP=
. It is perhaps doable with a policer that somehow has access to the TCP ac=
ks in the reverse direction and then can determine both RTT with a reasonab=
le accuracy and also if TCP ECE is modified according to (http://tools.ietf=
.org/id/draft-kuehlewind-conex-tcp-modifications-01.txt)=20
Or is this perhaps simpler ?

/Ingemar

PS
Realized that I got things a bit backwards in my question below, thought th=
at ECE is clamped to 1 for an RTT...

> -----Original Message-----
> From: Mirja Kuehlewind [mailto:mirja.kuehlewind@ikr.uni-stuttgart.de]=20
> Sent: den 14 november 2011 17:43
> To: conex@ietf.org
> Cc: Ingemar Johansson S
> Subject: Re: [conex] ConEx as sender side only modification
>=20
> Hi Ingemar,
>=20
> yes there are only sender-side modification needed. If you=20
> only have the 'classic' ECN, you will only be able to get (at=20
> max) one congestion notification per RTT. If there is more=20
> than one CE marking per RTT you will underestimate the congestion.
>=20
> Mirja
>=20
>=20
> On Monday 14 November 2011 11:16:04 Ingemar Johansson S wrote:
> > Hi
> >
> > Have not been able to follow the ConEx list in detail but reading=20
> > http://tools.ietf.org/id/draft-briscoe-conex-initial-deploy-00.txt
> > I can see that received side modifications are optional.
> > This is of course interesting at least if consinder the=20
> normal server=20
> > client architecture as it is easier to modify a million=20
> servers than a=20
> > zillion clients. Assuming that I read right...
> > How does it work with TCP, I know TCP modifications have been=20
> > considered to make TCP echo back the exact correct number=20
> of ECN-CE to=20
> > the server. Does this then mean that a TCP flow (unmodified=20
> TCP) will=20
> > state a higher congestion level in the dest-opts than the actual ?
> >
> > /Ingemar
> >
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > INGEMAR JOHANSSON  M.Sc.
> > Senior Researcher
> >
> > Ericsson AB
> > Wireless Access Networks
> > Labratoriegr=E4nd 11
> > 971 28, Lule=E5, Sweden
> > Phone +46-1071 43042
> > SMS/MMS +46-73 078 3289
> > ingemar.s.johansson@ericsson.com
> > www.ericsson.com
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > _______________________________________________
> > conex mailing list
> > conex@ietf.org
> > https://www.ietf.org/mailman/listinfo/conex
>=20
>=20
>=20
> --
> -------------------------------------------------------------------
> Dipl.-Ing. Mirja K=FChlewind
> Institute of Communication Networks and Computer Engineering=20
> (IKR) University of Stuttgart, Germany Pfaffenwaldring 47,=20
> D-70569 Stuttgart
>=20
> tel: +49(0)711/685-67973
> email: mirja.kuehlewind@ikr.uni-stuttgart.de
> web: www.ikr.uni-stuttgart.de
> -------------------------------------------------------------------
> =