RE: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002
Glen,
Referring to your comment about frame size distribution from actual traffic.
> 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).
Does anyone in the group have a traffic sample from a network transporting
digital video streams to give frame size distribution? For example, a
traffic sample for digital video over fiber to a VDSL ONU to serve several
hundred VDSL lines to a residential gateway. That scenario may be a good
one to look at for traffic on a residential GigaPON connected to multiple
VDSL ONU locations with data and switched digital video content.
-Kent
> -----Original Message-----
> From: Glen Kramer [mailto:gkramer@xxxxxxxxxxx]
> Sent: Friday, August 23, 2002 9:44 AM
> To: Thomas.Murphy@infineon.com; stds-802-3-efm@ieee.org
> Subject: 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
> >
>
>