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Re: [EFM] Re: [EFM-Copper] Long Reach Copper Presentations in Vancouver


I agree with John's remarks below.  I think EFM Copper should specify:

-Mapping of Ethernet MAC frames into PHY user data field (e.g. HDLC or 64B66B)

-Auto discovery

-Loop bonding

-Any other control function

-Applicability (or not) of MAC OAM PDUs over copper PHYs)


I think the actual PMD/transmission systems should be specified by ITU Q4/SG15 and by T1E1.4 for North America



Alan Weissberger
Data Communications Technology
2013 Acacia Ct
Santa Clara, CA 95050-3482
1 408 863 6042 voice
1 408 863 6099 fax

----- Original Message -----
From: John Farnbach
Date: Thu, 19 Dec 2002 10:11:42 -0700
To: Behrooz Rezvani
Subject: [EFM] Re: [EFM-Copper] Long Reach Copper Presentations in Vancouver

I'm a new kid on this block, so allow me a naive comment on the dialog about ADSL vs SHDSL.

I don't see why it is necessary in a practical sense to define any physical layer at all for EFM.  referring to slide 19 of jackson_copper_1_0702.pdf, why not simply define the EoDSL interface between the MAC and any PMD capable of carrying a clear channel byte stream.  That would make EFM future-proof to possible new DSL versions, it would provide a degree of backwards compatibility, since many carriers will have already deployed ADSL or SHDSL, and it will allow chip vendors the option of integrating the EoDSL function in xDSL tranceiver chips.

I guess I'm suggesting that the copper group just define both sides of Jackson's EoDSL layer and stop there.  Let the PMD standards ensure that they provide a compliant TPS-TC, which should only be a clear channel byte stream.

Best regards,
John Farnbach

Behrooz Rezvani wrote:

The offer is too tempting not to take
and I could disagree with intent, content, and context of your note


merry x-mass and
Happy new year


----- Original Message -----
To: ; ;

Sent: Thursday, December 19, 2002 1:02 AM
Subject: RE: [EFM-Copper] Long Reach Copper Presentations in Vancouver

> Barry,
> I believe that the point Howard made in Hawaii that a presentation per
side for #1 and #2 would be allowed should have prevented wasted effort on
your part. I am sure we all regret this has happened.
> I would also like to remind us all of the meeting in Edinburgh, where Dong
Wei's impassioned plea along with his presentation in support of #2
(g.SHDSL) were widely supported over the whole Task Force and had a majority
vote in the straw polls.
> Therefore, I believe that, given the fact that delays since that time seem
to have helped solidify support for #2 and against those continuing to delay
copper's advance, that it will achieve a strong vote and the only open
question will be: will #1 (ADSL Annex J) be able to justify the existence of
Annex J and the creation of yet another LR PHY that will somehow be
different (unique identity) than VDSL operating in the bands alread! y defined
for it (where ADSL J operates) and SHDSL already selected for the LR PHY. I
cannot see any justification for going back for another Objective and then
defining something that does not have a unique identity.
> Respectfully,
> John
> -----Original Message-----
> From: O'Mahony, Barry []
> Sent: Thursday, December 19, 2002 3:28 AM
> To: 'Howard Frazier';
> Cc:
> Subject: RE: [EFM-Copper] Long Reach Copper Presentations in Vancouver
> Howard,
> I disagree with your characterization that there are only two potential
> proposals.  Based on the agreed motion to "limit proposals for
> consideration regarding the long reach objective to those based on
> artman_copper_1_0702 and jackson_copper_1_! 0702", one can construct any
> number of proposals.  But among those proposals which have been actively
> discussed in the copper track over the past few meetings, they can be
> into three major categories:
> 1.)  those based on artman_copper_1_0702 only,
> 2.)  those based on jackson_copper_1_0702 only,
> 3.)  those based on artman_copper_1_0702 and jackson_1_0702.
> This is not just a subtle semantic difference.  I believe each of these is
> distinct, separate proposal category.  #3 is not merely a cop-out
> amalgamation of #1+#2, although it certainly may appear to be at first
> glance.    Unfortunately, artificially restricting presentations to only
> those based on #1 and #2 would make it difficult to dispell this first
> impression.
> For example, if for the sake of argument! , one accepts that both are needed
> in order to form a complete solution, one can hardly expect an advocate
> #1 or #2 to make the point that the other is deficient because it offers
> only a partial solution, as that would illuminate the fact that his/her
> proposal is similarly deficient.  This then leads to the argument over
> of the partial solutions is less partial than the other, which customers
> more imprtant than others, etc., far more subjective issues and a recipe
> the endless rathole discussions we've been having.
> There are other points to make along these lines, which for brevity's sake
> are best left to a presentation itself.  Technically, the key problem
> reconciling the long-reach objective and the spectrum management
> But aside from technical reasons, an approach where the only path into #3
is > as some sort of "consolation prize" when/if #1 and #2 fail seems to be a
> poor way to adopt a decision.  It's almost guaranteed to leave the
> impression that #3 was adopted only because the group could not make a
> decision between  #1 and #2, and lazily chose "both".    If number #3 were
> in fact to be chosen, far better that the group does it because they
> it is the best technical decision, and  have been given all the
> upon which to feel comfortable  making it.  Considering 802.3ah is a large
> subset of 802.3, it makes even more sense for all proposals to be
> to the entire Task Force.  I thought that was the intent of doing this
> during the Monday general session.
> Finally, I must mention that all three proposals, #1, #2, and #3 have been
> discussed in the copper track for a couple of t! he past meetings.  While
> has reached consensus, all have gotten significatn support; none are
> something new for this meeting.  In the announcement for this meeting sent
> out 11/22, it was stated that a significant amount of time would be
> in the Monday general session  to the issues of Long-Reach copper, FEC,
> PON PMD timing.  Presentations on proposals to address them would would be
> "welcome".  It was requested that the appropriate sub-TF editor be
> prior to 12/23.  In fact, I notified Hugh prior to Thanksgiving that I was
> planning on a presentation for the long-reach issue.  To now see, at a
> date when it would be expected that work on such presentations would be
> largely completed, that some presentations now appear to be considered
> "uwelcome", is very disappointing.  I fear it will feed int! o the
> in some quarters in the copper track that some opinions are dismissed
> without due consideration.
> --Barry
> -----Original Message-----
> From: Howard Frazier []
> Sent: Wednesday, December 18, 2002 10:10 AM
> To:
> Cc:
> Subject: [EFM-Copper] Long Reach Copper Presentations in Vancouver
> Dear Members of the IEEE 802.3ah EFM Copper Sub Task Force,
> There has been considerable discussion about the Long Reach Copper
> presentations that are being planned for the upcoming meeting in
> Vancouver.  I previously announced that we would reserve the
> entire day on Monday, January 6th for an "all hands" meeting of
> the 802.3ah EFM Task Force to consider sever! al "big ticket" items
> that require the attention and involvement of all of the Task Force
> members.  One of these "big ticket" items concerns our long reach
> copper PHY objective.
> Clearly, we need to resolve the question of how we are going to meet
> the long reach objective. Adhering to the motion that we passed last July,
> that limits our consideration to those proposals based on the Artman and
> Jackson presentations (advocating PHYs based on ADSL Annex J and
> g.shdsl, respectively), the task force has a finite set of choices:
> 1) Adopt the ADSL Annex J proposal (with appropriate updates)
> 2) Adopt the g.shdsl proposal (with appropriate updates)
> 3) Adopt both proposals
> 4) Adopt neither proposal
> It is obvious to me that choice # 4 above is the least desireable outcome.
> It is also the default outcome, because the first three cho! ices require a
> positive vote, while # 4 represents the status quo ante.
> In the hope that the Task Force can reach a >= 75% concensus on
> one of choices # 1-3, I request that we invest all of our efforts in the
> task of producing EXCELLENT material in support of ADSL Annex J,
> and EXCELLENT material in support of g.shdsl.
> Each of these proposals must stand on its own, and must satisfy the
> 5 Criteria. Each proposal must demonstrate that it has a Broad Market
> Potential, that it is Compatible with 802.3 and 802, that it has a
> Distinct Identity, that it is Technically Feasible, and that it is
> Economically Feasible.
> I have heard some individuals argue (quite eloquently) that both proposals
> must be adopted in order to satisfy the Broad Market Potential criterion.
> In my opinion, this is not the best argument to put forward. Neither
> 802.3ah > nor 802.3 will adopt a proposal that fails to satisfy all of the 5
> Criteria, and
> I fear that by saying that both proposals are required to satisfy the
> Market Potential criterion, we imply that neither proposal alone is
> sufficient to
> satisfy it.
> May I therefore strongly urge the proponents of each of the two proposals
> to concentrate on putting forward the best possible arguments in support
> of their proposal.  If the Task Force concludes that both proposals
> the 5 Criteria, and that both proposals should be adopted, then the Task
> Force will vote accordingly.  I do not intend to entertain a "shoot out",
> "choose one and only one" motion (though I may conduct a "beauty contest"
> type of straw poll, where I ask the Task Force members to indicate their
> favorite).  I intend to entertain motions on each of the proposa! ls
> individually,
> in the hope that the Task Force casts a >= 75% vote in favor of choice
> 1, 2, or 3, above.
> One last note about the interpretation of our long reach objective: I
> interpret our long reach objective, as we adopted it last July, to permit
> only ONE PHY for long reach copper.  This would seem to eliminate
> choice # 3 as an option. Based on past history, I don't think
> that we can successfully argue that choice # 3 really represents only
> one PHY.  As I have said before, our Task Force members may not each
> possess a Ph.D. in digital signal processing, but they can all count to
> two!
> Therefore, if we adopt choice # 3, I believe that we will have a follow on
> task to justify the choice, and to modify our objective(s) accordingly.
> we adopt choice # 3 on Monday, January 6th, I will assign an action item
> t! o the Copper Sub Task Force to carry out this task, and we will review
> their work on Thursday, January 9th in general session. We will then have
> to present the change(s) to the 802.3 Working Group when it meets in
> Howard Frazier
> Chair, IEEE 802.3ah EFM Task Force

John Farnbach, Managing Partner
Farnbach Associates

tel/fax: 303-448-9852
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