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Re: MMF PMD Selection

Dear All,

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"

Best Regards,

Dan Draper
Dan Draper
Microcosm Communications
A Division of Conexant Systems, Inc.
3000 NW Stucki Place  Suite 220
Hillsboro, OR  97124
Phone:  (503) 466-3002
Fax:       (503) 466-3050
E-mail:  daniel.draper@xxxxxxxxxxxx

                    "David Martin"                                                                                    
                    <dwmartin@nortelnetw        To:     stds-802-3-hssg <stds-802-3-hssg@xxxxxxxx>                    
          >                   cc:                                                                   
                    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
     installed base.

     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
Nortel Networks
+1 613 765-2901
+1 613 763-2388 (fax)


     -----Original Message-----
     From:   Bill Wiedemann [SMTP:billw@xxxxxxxxxxx]
     Sent:   Monday, July 17, 2000 9:34 PM
     To:     stds-802-3-hssg
     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
     vendors desires.

     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
     small form
     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
     to be
     sure that the clauses for WDM implementations keep up with the current

     progress on serial clauses.

     Bill Wiedemann
     925-560-1610  X169