Dear Tom,
Oops sorry - I made a mistake - I think its someone else :)
"Eggert - During the WG last call, there was some experience and
input that we would like to put in the user guide, particularly
clarifications for the loss interval and packet loss rate.
We have a student with some data, but it is not ready to
show yet.
a. Issue is packet size calculation (MSS or average?).
It is not definite in this draft, but you do need to agree.
b. Estimation of loss interval.
In TFRC, you are supposed to average over 8 samples.
Some implementations mess this up, if they have
less than 8 samples."
Regds,
Arjuna
On 4/20/06, Phelan, Tom <tphelan@xxxxxxxxxxxx> wrote:
> Hi Arjuna,
>
> See inline...
>
> Tom P.
>
> > -----Original Message-----
> > From: Arjuna Sathiaseelan [mailto:arjuna.sathiaseelan@xxxxxxxxx]
> > Sent: Thursday, April 20, 2006 10:53 AM
> > To: Jeroen Van Velthoven
> > Cc: dccp@xxxxxxxx
> > Subject: Re: TFRC average loss interval calculation
> >
> > Ok I went through the audio archive - and Tom Phelan points out the
> [Tom]
> I think it's pretty unlikely that I said that -- I'm as confused as the
> rest of you with regard to this. But I do remember that someone else
> said this, maybe someone speaking for Eddie's input from jabber.
>
>
> > same problem - that some implementations average the loss intervals
> > over 8 samples even though there are less than 8..So I guess - the
> > correct thing would be to average them based on the no of samples
> > currently available..So the ns-2 code needs to reflect the change..My
> > few cents - do correct me if I am wrong :)
> >
> > -A
> >
> > On 4/20/06, Arjuna Sathiaseelan <arjuna.sathiaseelan@xxxxxxxxx> wrote:
> > > Dear Jeroen,
> > > I concur with your views - I guess this question was raised in the
> > > recent IETF
> > > meeting. Maybe someone can shed proper light on this :).
> > >
> > > Regds,
> > > Arjuna
> > >
> > > On 4/20/06, Jeroen Van Velthoven <jeroen.vanvelthoven@xxxxxxxx>
> wrote:
> > > > Dear all,
> > > >
> > > > I am performing some experiments with DCCP/TFRC. Therefore, I'm
> using
> > the
> > > > DCCP implementation of Mattsson. My question relates to the
> > calculation of
> > > > the average loss interval as it is done by this implementation.
> As
> > > > specified the TFRC RFC, the 8 most recent loss intervals are used
> to
> > obtain
> > > > the average loss interval. However, also when the first loss
> event
> > occurs
> > > > and in every situation where the number of initialized loss
> intervals
> > is
> > > > strictly smaller than 8, this implementation takes the sum W_{tot}
> of
> > all 8
> > > > weights and uses this result to determine the average loss
> interval.
> > > >
> > > > I would assume that when the loss history contains only two loss
> > intervals,
> > > > it is sufficient to take only these weights into account when
> > calculating
> > > > W_{tot}. This would not result in an overestimate of the loss
> event
> > rate
> > > > you get by taking into account the total of the 8 weights.
> > > >
> > > > Can anyone confirm that the number of weights you need to use to
> > obtain the
> > > > average loss interval equals the minimum of 8 and the number of
> the
> > actually
> > > > created loss intervals?
> > > >
> > > > Best Regards,
> > > > Jeroen
> > > >
> > > >
> -------------------------------------------------------------------
> > > > Jeroen Van Velthoven
> > > >
> > > > Phone: +32 (0)3 265.38.53
> > > > Fax: +32 (0)3 265.37.77
> > > > Email: Jeroen.VanVelthoven@xxxxxxxx
> > > >
> > > > University of Antwerp (UA)
> > > > Dept. Mathematics and Computer Science
> > > > PATS Research Group
> > > > Campus Middelheim, building G
> > > > Middelheimlaan 1
> > > > B-2020 Antwerp
> > > > Belgium
> > > >
> -------------------------------------------------------------------
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > --
> > > Regards,
> > > Arjuna
> > >
> > > Postdoctoral Researcher
> > > Engineering Research Lab,
> > > Department of Engineering,
> > > University of Aberdeen
> > >
> >
> >
> > --
> > Regards,
> > Arjuna
> >
> > Postdoctoral Researcher
> > Engineering Research Lab,
> > Department of Engineering,
> > University of Aberdeen
>
>
--
Regards,
Arjuna
Postdoctoral Researcher
Engineering Research Lab,
Department of Engineering,
University of Aberdeen
