Re: MMF PMD Selection
I thought I heard a comment during the PMD discussions last week that a
large percentage of installed fiber was 62.5um 160 MHZ*km. While the 850nm
CWDM and 1310nm WWDM PMDs presented support this fiber to 100m, it is not
clear from any of the PMD presentations that they will support this
installed base to 300m. Is this correct? I may have missed this, but what
exactly is the modal bandwidth assumption when discussing "installed"
A Division of Conexant Systems, Inc.
3000 NW Stucki Place Suite 220
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Phone: (503) 466-3002
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<dwmartin@nortelnetw To: stds-802-3-hssg <stds-802-3-hssg@xxxxxxxx>
Sent by: Subject: MMF PMD Selection
07/19/00 10:41 AM
In the interest of making progress on the MMF PMD selection, and in
response to Bill's request for system vendor input, I'll paint a bright
red target on myself. Here goes.
Consider the following four distinct applications:
1. Dark fiber/SMF runs up to 40km & WAN interconnect (metro)
2. Dark fiber/SMF runs up to 10km & WAN interconnect (campus
3. MMF horizontal/vertical runs up to 100/300m (in-building)
4. New fiber (any type: ribbon, MMF, SMF) runs up to 300m
It is easiest to explain to customers what to deploy when there is a PMD
positioned to match each application (or ideally one that does all). I
serial 1550 for app-1, serial 1310 for app-2, 1300 WWDM for app-3 and
left app-4 for the OIF VSR work activity (as we don't have a general intra-
office interconnect objective, but could adopt/adapt their results in a
So why pick 1300 WWDM for app-3? My thinking:
a. It is the only solution which addresses up to 300m for all
That is really the end of the rationale. However, considering cost
b. 1300 VCSELs are supposedly only 6 months away (or up to 6 years
away depending on the source), which should make 1300 WWDM cost
competitive with 850 VCSEL WWDM.
Now I'll duck & cover.
David W. Martin
+1 613 765-2901
+1 613 763-2388 (fax)
From: Bill Wiedemann [SMTP:billw@xxxxxxxxxxx]
Sent: Monday, July 17, 2000 9:34 PM
Subject: RE: what's next ?
Jonathan, Thanks for your clarification on expectations for the
meeting in September.
I think it would be very helpful to have a discussion as to the
For example their interest in the current candidates for the 100 meter
300 meter objectives. 1300WWDM, 850CWDM, 850 serial.
What they would "need" to see/understand for these to gain their
and/or why they never will support one or all of these. My reason for
initiating this is that it will be very difficult to get any of these
approved unless we meet their expectations. I hope any of these aren't
approved as the lesser of evils.
Regarding 850CWDM we are planning to make first implementations with
SC moving to LC with small form factors. Our expectation is that
factor with LC could be available a year from today. First size will
GBIC, electrical interface can be XGMII or XAUI for first
Should we pursue equalization for 850CWDM to reach 300 meters over
62.5 um fiber?
We have had initial discussions with Brad Booth and David Cunningham
sure that the clauses for WDM implementations keep up with the current
progress on serial clauses.