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[802.3BA] Reach Objective for MMF


On this reflector we have had many discussion on the SMF reach 
objective.  But I want to bring
up your attention to the current MMF reach objective which is only 100 m. 

High density data centers switches will be based on the QSFP (XFP width) 
or the CSFP (~26 mm),
I do not see a viable serial 40G or 4x25G WDM solution in these form 
factor in near future. 
The current proposed 4x25G WDM will be housed in a double wide Xenpak 
(~81 mm).

Currently for reach larger than 100 m you must switch to 100 Gig 4x25G 
WDM!  Unless you are
designing your switch for reduce capacity double wide Xenpak will not 
plug in to a QSFP or CSFP!
 From pure density perspective you will be doing worse than dual stacked 
According to Allan Flatman study page 7 
300 m covers the building backbone and for larger data center more than 
100 m may be needed.

In Atlanta I showed how even with sub 10G laser "300 m link on OM3 fiber
with linear receiver has 1 dBo less penalty than 100 m link OM3 with 
limiting receiver"

I would like to explore the possibility of increasing the reach 
objective on OM3 fiber from 100 m to
220 m or 300 m.  I do understand the draw back of ribbon cable, but here 
we have situation where
the 4x25G solution just doesn't fit in to a QSFP/CSFP.  Maybe after a 
season on biggest looser it might fit :-)

Happy Holiday,


fn:Ali Ghiasi
adr;dom:;;3151 Zanker Road;San Jose;CA;95014
title:Chief Architect