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Re: [HSSG] 40G MAC Rate Discussion

The QSFP MSA is complete and supports 4X 10G for optical and copper. 

So it would be very easy to use 4 lanes of the 10 lane PMD and reference
this MSA.


-----Original Message-----
From: Marcus Duelk [mailto:duelk@ALCATEL-LUCENT.COM] 
Sent: Friday, April 06, 2007 10:58 AM
Subject: Re: [HSSG] 40G MAC Rate Discussion


aren't there already 40G (i.e. 4x10G) transceiver out there ?
I know at least of one transceiver company that is offering these
devices today, there is also the X40 MSA group:

So I get the impression that the PMDs (including SMF) are
already existing, it is maybe more a matter to have a MAC
that supports this as one logical 40G pipe. But then we are
back at that discussion what the difference to 4x10G LAG is,
I assume ...


Matt Traverso wrote:
> I'd like to comment from an optical component / module vendor point of

> view.
> Personally I'm not convinced that broad market potential has been
> demonstrated, but... Operating under the assumption that the 40GbE
> broad market potential is verified with end user input:
> - As we heard/saw in Jack Jewel's presentation focused on the cost &
> reliability of the MMF objective, extending from a 1x10G VCSEL to a
> 10x10G VCSEL does not represent a linear cost increase -- similarly a
> 4x10G would only be an incremental increase
> - The dominant cost in a nx10G MMF interface is likely to be any
> premium charged for the interface IC as well as costs associated with
> the development quad laser drivers & quad amplifiers (or deka drivers
> & amps)
> - I'd like to hear a comment / perspective from the fiber
> manufacturers on the utilization rate of the ribbon fiber strands.
> For a 4x10G MMF approach presumably 8 strands in the 12 ribbon would
> be used 4 for TX and 4 for RX.  For a 10x10G MMF approach it would be
> 2 @12 with 10 @ Tx and 10 @ RX.  What does this do to the cost and
> usage rate metrics of MMF cabling?
> - Would an SMF PMD objective at 40GbE have broad market potential
> (BMP)?  Here I am very skeptical
> - Assuming that BMP was shown for an SMF PMD objective, I would
> advocate a 2km serial 40Gbit/s scheme rather than a 4 lambda approach
> as the transmission problems are not as severe
> - This would represent the path that reuses the most technology and
> allows for a compact & low power dissipation end solution
> - As I have stated one of the primary impediments is the availability
> of a low power interface IC -- this is the primary obstacle for OC768
> (40G SONET/SDH) modules
> - A 4 lambda x 10G at single mode would not simply be able to plug in
> the work done on 802.3ae as the technical challenge of MUX/DMUX
> optical loss and packaging would require a new round of investment
> In closing I'd like to see some supporting data for the Broad Market
> Potential of 40GbE (including distance / media usage
> comments/assumptions) that reflects the timeframe of standard
> development -- eg. demand/need in 2009-2012.
> thanks,
> --matt traverso
> NOTE: This e-mail is being sent from my personal e-mail account rather
> than my corporate e-mail address at Opnext due to default signature
> files embedded in my Opnext e-mail account.

Marcus Duelk
Bell Labs / Alcatel-Lucent
Crawford Hill HOH R-237
791 Holmdel-Keyport Road
Holmdel, NJ 07733, USA
fon +1 (732) 888-7086
fax +1 (732) 888-7074