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Re: [EFM] EFM Requirements

Thank you very much!


Sherman Ackley wrote:

> I am happy to answer your questions.
> Q1.  The need for three simultaneous video channels is supplier driven under
> the assumption that there is only one pair per house in the distribution
> plant.  Fact is that there is nearly always two pairs per house.  Actual
> usage statistics show that there is seldom ever a demand for three
> simultaneous channels.  In the rare case where there is a third or fourth is
> required, it is cheaper to provision on the second pair than to burden all
> subscribers with the higher costs.  What we are seeing is that customers who
> want and are willing to pay for high bit rate DSL/EFM also want the traffic
> to go in both directions equally well and have routable fixed IP addresses.
> Q2.  Picking the technology with the longest reach possible will make the
> difference between financial success and failure for the service provider.
> There are technologies working today that can provide EFM with bit rate
> reach in excess of ADSL's one way reach.  If the technology will only reach
> 1.5 km, then it cannot compete against Hybrid Fiber Coax or Satellite
> video/data networks in terms of cost per revenue producing subscriber.
> Q3.  (a) For DSL/EFM to succeed in the marketplace, it is necessary that a
> technician does not have to be dispatched to the home to install a splitter.
> (b) In a splitterless environment, the network signal and the HomePNA signal
> will ride the same cable pair in the house.  That makes coexistence a
> necessity.  The reason for this is that pair one will appear in every jack,
> but pair two may be cut off in the majority of homes. (c) For information on
> the HomePNA standard please go to
> Please feel free to ask more questions.  I hope this helps the understanding
> of the target market.
> -----Original Message-----
> From: Vladimir Oksman [mailto:oksman@xxxxxxxxxxxx]
> Sent: Monday, August 13, 2001 4:19 PM
> To: Sherman Ackley
> Cc: Stds-802-3-Efm (E-mail)
> Subject: Re: [EFM] EFM Requirements
> Dear Sherman,
>      thank you very much for this significant and really helpful input. A
> couple
> of questions for clarification anyway.
> 1. By your experience only two MPEG-2 channels are required. Why, however,
> US
> telcos were pushing so strong for 22Mb/s downstream for VDSL motivating that
> by
> a need in 3 video channels. Is there some specifics in video service over
> Ethernet you keep in mind?
> 2. You mentioned loop length of 10-12 km. It seems to me that the technology
> will allow 1-1.5 km. Does it still make sense to work on EFM?
> 3. You mentioned compatibility with HPNA. Here several questions come to the
> mind.
>     A. Is it right that you assume EFM running over the home wiring?
>     B. If yes, do you mean HPNA running over the same wire with EFM or over
> different wires?
>     C. What kind of HPNA do you keep in mind (there is no standard on HPNA)?
> Thankfully,
> Vladimir Oksman, Broadcom Corporation.
> Sherman Ackley wrote:
> > Service Provider Requirements for Ethernet in the First (two) Mile(s):
> > Sherman L. Ackley, CTO
> >
> > The National Rural Telecommunications Cooperative provides services to
> over
> > 350 member independent telephone companies who serve over 6 million access
> > lines.  Ethernet in the first mile is the most promising technology for
> the
> > delivery of integrated voice, video and data services in the suburban and
> > rural areas served by our Members.  As the Chief Technology Officer for
> > NRTC, I would like to submit some practical requirements as seen by the
> > service providers most likely to implement this technology in the USA.
> The
> > intent of this contribution is to help the study group prepare the
> > requirements document based on actual needs.
> >
> > The user locations will be 90 percent residential and 10 percent business.
> > Of those businesses, 90 percent will have 10 or fewer PCs.
> >
> > The system must work over standard high capacitance telephone outside
> plant
> > cable.  Binder group integrity is not assured.  The technology should not
> > force removal of bridge taps and end sections.  It needs to operate
> without
> > degradation at binder group fills over 70%.
> >
> > System reach is the most important aspect of the design.  Ethernet in the
> > first mile must operate over the longest reach possible.  The number of
> > households and small businesses served by a node is proportional to the
> > square of the reach.  For example, a reach of 3 km can serve about 100
> > single-family homes per node. Doubling the reach to 6 km increases the
> homes
> > served per node to 400.  And with a 12 km reach, 1600 homes per node can
> be
> > served.  This assumes 100 percent subscribe.  At 25 percent subscription,
> > short reach technology gets down to some dismal financial outlooks in
> terms
> > of cost per revenue producing subscriber as well forcing the construction
> of
> > too many street corner server nodes.
> >
> > Coexistence with HomePNA on the same cable pair is essential.  This
> feature
> > will be necessary in over 75% of households served with Integrated
> Broadband
> > services.  For example, a data stream of 10 Mbps will support two MPEG-2
> > high-resolution standard TV signals.  The DSL will carry this to the
> primary
> > service set-top box/home gateway that can be located anywhere in the
> house.
> > The Gateway device will terminate the video and data for use at the
> primary
> > TV, it will then forward the second video and data over the same cable
> pair
> > to other set-top boxes and PCs within the house using HomePNA.
> >
> > Peer-to Peer (or server to server) communications requires that the
> service
> > be adaptable so that full rate is available upstream or downstream as
> > required by the user generated traffic.  For example, it is now possible
> to
> > record MPEG-1 video on a camcorder and e-mail it over the Internet.
> > Unfortunately, sending the e-mail over a conventional fixed data rate
> > ADSL/VDSL system takes forever for the 20 Mbps file.
> >
> > There is little demand for sending three simultaneous MPEG-2 video streams
> > to the home.  This is based on the analysis of over 20 million DBS and
> > digital cable subscribers.  In fact, two streams are required in only 30
> > percent of households.  It is far more economical to install a second
> > Ethernet Subscriber Loop (ESL) for the one in 100 who want three HDTV
> videos
> > than to burden all with the high costs required to support a higher bit
> rate
> > short reach technology such as VDSL.
> >
> > In conclusion, long reach is of paramount importance.  For delivery of two
> > Standard TV signals, 10 Mbps at 12 km is required.  For one HDTV plus one
> > Standard TV, 20 Mbps at 12 km is desired.  Also, the selected technology
> > should allow data to flow in either direction at the full data rate.
> > Finally, the technology should be spectrally compatible with HomePNA
> without
> > requiring the use of a splitter at the residence.
> >
> > Finally, feedback on these ideas from other service providers and vendors
> is
> > invited.