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Re: [802.3BA] Longer OM3 Reach Objective

Hi Ali,

I agree with you as per our joint presentation.

The purpose of my email was to highlight that a linear interface is
not the only way to get extended reach.  A retimed interface has
already proven its ability to meet multiple distance objectives
(including 300m over OM3).

Best Regards,

> From: Ali Ghiasi []
> Sent: March 25, 2008 7:09 PM
> To:
> Subject: Re: [802.3BA] Longer OM3 Reach Objective
> Ryan and Others
> The standard should not dictate or force an specific implementation in
> 802.3ba.  Any module which has a gearbox does inherently retiming.
> Assuming the MAC ASIC electrical interface has minimum functionally
> i.e. nxXFI "XLAUI/CAUI it can directly interface to any module with
> gearbox which
> retimes the data without any PMA-PMA device.  But, if the PMD is based
> on nx10G then you may need retimer and/or equalizer to drive these
> PMDs.
> If the MAC SerDes has better jitter performance and/or equalizer it
> may be able to drive all PMDs without any external retimer or PMA-PMA.
> For smaller module form factors like QSFP or CSFP if there is a
> retiming and/or equalizer it is expected to be external.  Again the
> interface is optional and should not be forced to be in the module
> unless there is a mux/de-mux in the module, this allow overtime
> elimination
> of this function when the MAC ASIC SerDes performance improves.
> The question of limiting and linear PMD is separate from the having an
> XLAUI/CAUI, having the optional PMA to PMA each PMD
> electrical decision can be made standalone without impacting all the
> pieces of the puzzle.
> Thanks,
> Ali