RE: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002
Kent,
The work that I did with video over GbE indicated that the frames were
severely bi-polar. Blocks of very large frames that was dependant on the
resolution and compression of the video codec with very small frames
interspaced between them. The amount of bandwidth is very dependant on the
compression ration and the resolution as well as the refresh rate. The
amount of buffering in the codec devices also played a major role in the
maximum bandwidth peak that the data frames required.
Thank you,
Roy Bynum
At 03:22 PM 8/23/2002 -0700, Mccammon, Kent G. wrote:
>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
> > >
> >
> >