RE: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002
Tom:
I had made a presentation in the last EFM meeting addressing
exactly this issue. I broke down the overhead into its
components and did a performance analysis.
You can find the presentation at the following URL:
http://www.ieee802.org/3/efm/public/jul02/p2mp/gummalla_p2mp_1_0702.pdf
Hope this helps answer your questions.
Ajay
> -----Original Message-----
> From: owner-stds-802-3-efm@majordomo.ieee.org
> [mailto:owner-stds-802-3-efm@majordomo.ieee.org]On Behalf Of
> Thomas.Murphy@xxxxxxxxxxxx
> Sent: Friday, August 23, 2002 12:55 PM
> To: gkramer@xxxxxxxxxxx; Thomas.Murphy@xxxxxxxxxxxx;
> stds-802-3-efm@ieee.org
> Subject: AW: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002
>
>
>
> Hi Glen,
>
> Thanks for the reply. Would it be possible to formulate
> the statements below into an Excel data-sheet which could then
> be used as a basis for discussion? I know that there has been some
> work in this direction and my hope is to generate one tool which
> has been accepted by the majority and can be used by all.
>
> Regards
>
> Tom
>
>
>
> -----Ursprüngliche Nachricht-----
> Von: Glen Kramer [mailto:gkramer@xxxxxxxxxxx]
> Gesendet am: Freitag, 23. August 2002 18:44
> An: Thomas.Murphy@infineon.com; stds-802-3-efm@ieee.org
> Betreff: RE: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002
>
> Tom,
>
> This is to address action item #2 from the minutes.
>
> 2. Efficiency model based on guard bands and traffic type - P2MP group?
>
>
> There are 3 types of overhead (or bandwidth loss):
>
> 1. Cycle overhead. This is overhead used by guard bands (including CDR).
> It is measured as a number of guard bands in one cycle. This number at
> least equal to the number of ONUs, but may be even larger if we grant
> per LLID and there are multiple LLIDs per ONU.
>
> 2. Slot overhead. This overhead arises when granted slot does not take
> into account frame delineation in a buffer. Since frames cannot be
> fragmented, a frame that doesn't fit in the remainder of a slot will be
> deferred to next slot (in next cycle), leaving current slot
> underutilized.
>
> The size of unused slot remainder depends on frame size distribution.
> This distribution for today's traffic is known and there exist formula
> to calculate this unused remainder (for the case when assigned slot size
> has no correlation to the frame sizes).
>
> Few protocol proposals consider how to eliminate unused slot remainder
> completely, but it looks like it will require changes to the frame
> format. P2MP group is still debating about it.
>
> 3. Frame overhead. That includes IFG and headers. Nothing we can do
> about it.
>
> Glen
>
> > -----Original Message-----
> > From: owner-stds-802-3-efm@majordomo.ieee.org
> [mailto:owner-stds-802-3-
> > efm@xxxxxxxxxxxxxxxxxx] On Behalf Of Thomas.Murphy@xxxxxxxxxxxx
> > Sent: Friday, August 23, 2002 1:57 AM
> > To: stds-802-3-efm@ieee.org
> > Subject: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002
> >
> > Hello All,
> >
> > First off I apologise for sending this mail to the
> > EFM reflector, however, a number of issues arose which
> > are relevant for other groups.
> >
> > The next phone conference is planned for next Thursday
> > at the old time of 11:00 Eastern
> >
> > Regards
> >
> > Tom
> >
>
>
>