RE: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002
Hugh,
You uncovered that I still have a copperhead mentality or should I say Bell
Shaped Head. But, I am flying the fiber flag now. However, I sometimes can
be observed attending copper subgroup meetings to participate in the latest
vote in linecode battles.
You answered my request with a GigE link between central office and a remote
VDSL ONU. I was asking about the use of P2MP interfaces rather than P2P
GigE for Hybrid Fiber/Copper architectures. With the expected efficiency of
P2MP, could an operator feed 4 VDSL nodes with 200 subs each? Or would point
to point GIgE be needed for each VDSL node? I like conserving my embedded
feeder fiber if I can! I like single fiber P2P and PON for reducing fiber
cost whether making the most use of what fiber is there or planning large
deployments that scale.
-Kent
> -----Original Message-----
> From: Hugh Barrass [mailto:hbarrass@xxxxxxxxx]
> Sent: Friday, August 23, 2002 3:52 PM
> To: Mccammon, Kent G.
> Cc: 'gkramer@xxxxxxxxxxx'; Thomas.Murphy@xxxxxxxxxxxx;
> stds-802-3-efm@ieee.org
> Subject: Re: [EFM] Minutes of P2MP Optics conference 22nd Aug 20002
>
>
> Kent,
>
> 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).
>
> Hugh.
>
> "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.
> >
>