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I agree with what you say; my preference has been/is to add another objective but there has been reluctance by others to add another PMD for several reasons including that we will get wrapped around the distinct identity issue even though we have violated that "critter" in the past. So we have been trying to exhaust other avenues prior to adding an objective.
I think my position is clear:
Bottom-line: The only thing that I would oppose is a 100m-only solution; I would support any means to get to an extended reach solution that we can get consensus on but it is not clear to me what that is........
From: John DAmbrosia [mailto:jdambrosia@xxxxxxxxxxxxxxx]
Sent: Thursday, July 10, 2008 10:38 AM
To: Swanson, Steven E; STDS-802-3-HSSG@xxxxxxxxxxxxxxxxx
Subject: RE: [802.3BA] XR ad hoc Phone Conference Notice
Your comment below could be interpreted that something has stopped the group from making a motion regarding a new objective for MMF. I do not recall any motion (or straw poll) regarding adding a 2nd MMF objective ever being made. This is different than the SMF scenario described below, where separate motions for each of the distances were made. (> 10km over SMF adopted Motion #5 11/06 plenary meeting and > 40km over SMF adopted Motion #5 at 1/07 interim meeting).
Furthermore, I gave a presentation to the XR over Parallel Fiber Ad hoc (http://www.ieee802.org/3/ba/public/AdHoc/MMF-Reach/dambrosia_xr_01_0508.pdf) where the topic was discussed as well in relation to distinct identity. I also addressed this issue in an email to Paul Kolesar (http://www.ieee802.org/3/hssg/email/msg01162.html), and observed that I saw three general routes that the ad hoc might choose in forming a proposal:
1) handle extended reach in some sort of informative manner
2) modify the existing solution in some manner
3) propose a new objective that enables a second solution
To date I have still not heard anyone propose adding a new objective. If such a course were to be pursued, it would be advisable to do at the coming plenary meeting, so that the added objective could be confirmed by the WG.
Steven E [mailto:SwansonSE@xxxxxxxxxxx]
Just to be crystal clear, the objective reads:
"at least 100m on OM3 MMF"
While I agree that 100m
meets that objective, Kolesar and I presented data in November 2006 noting that
100m was not adequate. We were assured that longer link lengths could be
accommodated because of the words "at least." This was my beef in
In a survey of our customers 0/20 said that 100m was adequate and that MMF was preferred over SMF where possible.
I still don't understand why it is OK to have two link length objectives for SMF (and we considered a third (2-4km)) but we can't have two link length objectives for MMF. Better yet from my point of view is to have one PMD that satisfies both - the premium that we are talking about at the module level (estimated at ~20%) is in the noise for 40/100.
We need a compromise here of some sorts.
That's an excellent point. I'm glad that Jeff brought this up.
The objectives state 100m on OM3. That is the requirement of the project and one by which the draft standard will be judged. There is no requirement to satisfy a non-objective.
From: Jeff Maki