Re: [802.3BA] Longer OM3 Reach Objective
I agree with you as per our joint presentation.
From: Ali Ghiasi [mailto:email@example.com]
Sent: March 25, 2008 7:09 PM
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
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
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
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.