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RE: [EFM] EFM Requirements

It is great to get more practical field experience and information to help
in defining the requirements for the EFM working group.

Seems we are arriving at a consensus that some things that are important
requirements.  These include:
1. Reach is mort important than raw bit rate.
2. Self install by an untrained consumer is a must.
3. The home network hides behind a gateway/firewall of some kind for
security resons.
4. There are at least 5 home networking technologies.  These are 10-baseT on
new dedicated CAT5 data wiring, HomePNA on the existing phone line, 802.11
wireless and HomePlug over the power line, and I almost forgot HomeRF
(excuse me for saying it to an 802 group)
5. You cannot predict what consumers will use it for, therefore the data
rate needs to be dynamically allocable between downstream and upstream

When multiple services ride over the same physical media, it is desireable
that they not interfere with each other.

One of the best frequency coordination jobs was done by the video industry.
It is possible to place Cable Modem, off air TV, CATV and DBS on the same
coax without interference.  Today, the same is true with analog voice, ADSL
and HomePNA.  It is not true with VDSL.

Since you install DOCSIS modems, did you notice that you can put the modem
on any video outlet and it works.  You can also move it to another room and
it will work.

It would be interesting to find out what percent of ADSL installations use
splitters versus filters.  Does any one have any statistics on this?

-----Original Message-----
From: Fletcher E Kittredge [mailto:fkittred@xxxxxxx]
Sent: Wednesday, August 15, 2001 12:23 PM
To: Sherman Ackley
Cc: Stds-802-3-Efm (E-mail)
Subject: Re: [EFM] EFM Requirements 

On Mon, 13 Aug 2001 11:31:06 -0400  Sherman Ackley wrote:
> Coexistence with HomePNA on the same cable pair is essential.  This
> will be necessary in over 75% of households served with Integrated
> 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
> service set-top box/home gateway that can be located anywhere in the
> The Gateway device will terminate the video and data for use at the
> TV, it will then forward the second video and data over the same cable
> to other set-top boxes and PCs within the house using HomePNA.


	I'm in the rural Northern New England market.  We have a fair
number of rural phone companies up here; they serve about 18% of the

	I don't understand the "essential" statement above.  Does this
mean that if EFM doesn't work with HomePNA, EFM is worthless or is
there some other definition of "essential".  Where the 75% figure
comes from?

        It sounds like you have a good, detailed understanding of how
the customer will use this protocol.  My experience has been that it
is difficult to predict in less than the most general terms how
a protocol will be used.  Two illustrations which are vivid to me are
ATM, which was to replace the Internet protocols, and DSL, which was
to allow video on demand over phone lines.

> Finally, feedback on these ideas from other service providers and vendors
> invited.

I think your emphasis on the importance of reach is spot on and I
could not agree more.  I think the analysis of how the service will be
used should not be used to make decisions.  It is impossible to know.