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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
> > 
> 
>