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Re: Equalization and benefits of Parallel Optics.

Paul and Bruce:

I appreciate both of you in devoting more attention to sub-300 meter fiber 
requirements.  I believe many people have different interpretation of sub-300 
meter needs, which is more complex than we like to see.

In reality, there are equipment jumper cables (20 meter or less), computer 
room cables (100 meter or less, and premises, building-to-building, campus 
(300 meter) cables, All of them were treated differently by LAN people in 
cost, quantity, handling, and implementation objectives.  These are the 
reasons, so far we cannot reach the consensus to have only 1310 nm WWDM for 
all under 300 meter applications.

If we continue to open up more discussion in sub-300 meter connections, and 
add sufficient varieties of PMDs, we may eventually gain more understanding 
from over 75% of voters to reach consensus.


Ed Chang     
NetWorth Technologies, Inc.


 We are free to add additional objectives as we see the need.  But when we 
 crafted and debated the 300 meter objective everyone who spoke on the issue 
 in the ad hoc, in the study group, and during the meeting in York referred 
 to either installed fiber links in building and campus backbones or pulling 
 new fiber into the same building and campus backbones. Even without the 
 word installed in the objective, the 300 meter value was justified in terms 
 of the lengths of campus and building backbone links.
 If we need an objective to support storage applications, lets investigate 
 what is needed and come up with an objective based discussion and data.
 At 10:44 AM 7/28/00 -0700, Paul Bottorff wrote:
 >I'm not certain the entire group sees the 300 m objective in the same way. 
 >Since the 300 m is not installed fiber it can be argued that it is not an 
 >objective for a high percent of installed fiber runs. The committee 
 >decided to address only 100 m installed fiber. SAN applications might 
 >require runs longer than 100 m and therefore may be well served by 300 m.
 >I don't  want to argue in favor of parallel ribbon for SAN applications. 
 >Though parallel ribbon will be used for rack jumpers a single fiber 
 >solution is a much more desirable long term answer for SANs. I believe we 
 >should not standardize parallel ribbon, especially at 300 m, however a 300 
 >m serial MMF solution for SANs does seem appealing.
 >At 04:25 PM 7/27/2000 -0700, Bruce Tolley wrote:
 >>Paul and Brad:
 >>I do not think the 300 meter objective was written with computer rooms in 
 >>mind.  It was written with building and campus backbones in mind.
 >>This was the context of the discussion within the distance ad hoc leading 
 >>up to the York meeting.
 >>My recollection from the York meeting is that we started discussing an 
 >>objective for 300 meters on installed fiber and ended up with consensus 
 >>on  objective that omitted the word "installed. "
 >>At the time, it seemed to me to be a compromise between those who wanted 
 >>to support the installed base with 1300 WWDM and those who wanted to 
 >>support 850 serial PMDs on new MM fiber.  Both sets of voters were 
 >>thinking in terms of building and campus backbones. The distance value of 
 >>300 meters itself has always been justified on the basis that it covers 
 >>some substantial percentage of the installed base of building and campus 
 >>At 02:35 PM 7/27/00 -0700, Booth, Bradley wrote:
 >>>Thanks for pointing that out.  I stand corrected.  The parallel optics and
 >>>parallel fiber could be applied to the 300m over MMF objective.  Although 
 >>>does meet that objective, the previous emails were targeting parallel
 >>>optics/fiber for the 100m application, and I should have probably 
 >>>my statement with that.
 >>>If it is only going to meet the 300m over MMF objective (and from Pat
 >>>Gilliland's presentation, only on new high bandwidth MMF), then I have the
 >>>same problem with this solution as I do with the 850nm Serial PMD 
 >>>They may both be the lowest cost today, but they don't satisfy the 100m 
 >>>installed MMF objective.  Considering we have two PMDs that are under
 >>>consideration to meet both the 100m over installed MMF and 300m over MMF
 >>>objectives, I believe it would be in the Task Force's best interest to 
 >>>on those solutions.  That is just my humble opinion.
 >>> >>