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Re: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002


It's great to see you're flying the "hybrid fiber/copper" flag!

Most video codecs are designed to spit out monotonic streams of (nearly) equal
sized frames. These frames will either be at the MTU size or as long as the VSP
dares to make them (many will limit the frame size to 1024 bytes for
superstitious reasons). The data stream will consist of many (i.e. >20) frames
at the maximum size followed by one short frame.

Note that a gigabit link will be able to carry 200-400 streams of unicast or
multicast video, so it will take a large number of subscribers to fill the pipe
(& therefore stress the efficiency).


"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.