RE: [EFM] Video distribution
John,
I agree with your comments about higher efficiency when broadcasting video
to all VDSL nodes. The PON capacity is a constraint for designing the
system. VOD of course changes the numbers as that traffic would be node
specific and customer specific depending on the type of VOD service. If the
PON throughput looks to be insufficient considering all services needs;
broadcast, VOD, telephony, and data services, an operator could plan for a
smaller split ratio to the VDSL node. The differential path loss
(attenuation range) specification of the optics should be made broad enough
to handle PONs with low splits for VDSL, for example 1x4 while other
operators deploy for large splits for FTTH such as 1x32 architectures. Thus,
the operator could have architecture flexibility in the selection of the PON
split ratio for the services planned.
-Kent
> -----Original Message-----
> From: John Limb [mailto:limb@xxxxxxxxxxxx]
> Sent: Monday, August 26, 2002 9:50 AM
> To: 'Mccammon, Kent G.'; stds-802-3-efm@ieee.org
> Subject: RE: [EFM] Video distribution
>
>
> Kent,
> I'm a little confused. Perhaps you could straighten me
> out. If you are distributing digital video from the OLT to
> ONUs (even if connected to a VDSL
> DSLAM) I would not think that you would need to have an
> unused slot remainder since the OLT scheduler could start one
> packet as soon as the previous one finished. If you were
> sending packets from the ONT to the OLT then I could see that
> slot remainders could occur.
> If you are serving several hundred subs then you would
> probably want to do mostly broadcasting rather then VOD. You
> would probably want to use variable rate video coding (rather
> than constant rate) in order to get a little more efficiency
> and some statistical averaging. Even so, I suspect that most
> packets would be max size (as Hugh says).
> If you assume an average rate of 3 Mb/s for a high
> quality video stream (probably even a little high for some of
> the newer VBR codecs) 200 streams would take about 600Mb/s
> leaving (plenty?) of room for other data, again confirming Hugh.
>
> John
>
> -----Original Message-----
> From: owner-stds-802-3-efm@majordomo.ieee.org
> [mailto:owner-stds-802-3-efm@majordomo.ieee.org]On Behalf Of
> Mccammon, Kent G.
> Sent: Friday, August 23, 2002 6:22 PM
> To: 'gkramer@xxxxxxxxxxx'; Thomas.Murphy@xxxxxxxxxxxx;
> stds-802-3-efm@ieee.org
> Subject: 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
> > >
> >
> >
>
>
>