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RE: 3PMD Proposal

      the offset launch patchcord is assumed for the 1300 nm WWDM case for
10 Gigabit Ethernet.  As was documented in IEEE 802.3z 1000BASE-LX the
offset launch patchcord ensures a worst-case minimum bandwidth of 500  For 1300 nm links the inclusion of the offset launch patchcord
obsoleted the 385 modal bandwidth value that was present in some
older drafts of the 1000BASE-LX clause.

In conclusion, since the offset launch patchcord is part of the 1300 nm WWDM
proposal 500 is the correct modal bandwidth to use for the multimode

Best wishes,


-----Original Message-----
From: Bernd.Prediger@xxxxxxxxxxxx [mailto:Bernd.Prediger@xxxxxxxxxxxx]
Sent: Wednesday, June 07, 2000 9:49 AM
To: piers_dawe@xxxxxxxxxxx
Cc: Stds-802-3-Hssg@xxxxxxxx
Subject: 3PMD Proposal

Hello Piers,
I just got through Del's presentation from Ottawa again and stumpled over
your calculation for the "Minimum Range" of CWDM over installed MM-Fiber
(Slide 4).
You calculated 2-300m for all 500MHz*km fiber but I understood that since
Gigabit Ethernet the worst case effective bandwidth everbody agreed on is
375MHz*km. Our calculation with the latter value let to about 180m.
What am I missing here? (Of course we used your spreadsheet!)
Best wishes