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RE: MMF PMD Selection

Title: MMF PMD Selection
Further Observation:
It seems, from comments on the reflector, those voted for 3 PMD have genuine belief of their decision based on the following assumptions, which I respect as different views.
1. 1550 nm is the best choice for MAN, 40 km -- We all agree
2. 1 310 nm serial is the right choice for campus, 10 km (or 2km) - We all agree.
3. 1310 WWDM only is sufficient for the rest of shorter distances - 42% agree, 58% disagree.
The items 1, and 2 are non-issues.  However, item 3 is an issue.  The possible reason that 3-PMD voters believe item 3 is viable is the overly simplified assumption, or the lack of appreciation of the complexity of short-reach requirements
As many individuals have mentioned that the market share of the 100/300-meter distance is about 80% of the total market.  For example, in a typical computer room, there will be over a hundred 10GbE nodes to interconnect equipment (less than 100meter mostly, or some less than 300 meter), and yet it only needs one or two 10 GbE nodes to reach outside (10 km, or 40 km).
As a result, the short reach nodes need the most cost-effective technologies to keep the over-all cost down.  The 1310 WWDM only cannot provide that goal.  It also requires the 850 nm VCSEL technologies to meet the market demands of cost-effectiveness.  This is the reason why 5 PMD is necessary, and 3 PMD is insufficient.
It may help HSSG to reach consensus regarding to 3-PMD or 5-PMD, if 850 nm VCSEL voters can provide more actual installation examples to help 3-PMD voters to appreciate the needs of more PMDs.


Edward S. Chang
NetWorth Technologies, Inc.
Tel: (610)292-2870
Fax: (610)292-2872

-----Original Message-----
From: owner-stds-802-3-hssg@xxxxxxxx [mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of Edward Chang
Sent: Wednesday, July 19, 2000 3:35 PM
To: David Martin; stds-802-3-hssg
Subject: RE: MMF PMD Selection

The PMD issue is much more than you have presented.  This is the reason, the 3-PMDs was not voted in.
The 1550 and 1310 serial are not the issue.  The issue is the installed MM fiber, 100 meter or less, or any MM fiber up to 300 meter.  This is the majority of market (80% or more), and the users want the most cost-effective cables, but not any cable at any cost.
Just look at the voting records we had in La Jolla, which is not as straight forward as we like to see.
Try to present a creative solution which will include five PMDs.


Edward S. Chang
NetWorth Technologies, Inc.
Tel: (610)292-2870
Fax: (610)292-2872

-----Original Message-----
From: owner-stds-802-3-hssg@xxxxxxxx [mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of David Martin
Sent: Wednesday, July 19, 2000 1:41 PM
To: stds-802-3-hssg
Subject: MMF PMD Selection


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 backbone)
  3. MMF horizontal/vertical runs up to 100/300m (in-building)
  4. New fiber (any type: ribbon, MMF, SMF) runs up to 300m (intra-office)

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 voted
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 later

So why pick 1300 WWDM for app-3? My thinking:

  1. 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 arguments:

  2. 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)