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Re: Link Status thoughts and other status signals


Thank you for your explanation.  I do believe that it is the PCS that would 
be setting the signalling rate, not the PMD.  The presence of a WIS as the 
PCS2 sub-layer would determine if it is a LAN PHY at ~10.13Gb signal rate 
or a WAN PHY at ~9.85 signal rate.  The PMD may need to know this, or it 
may not.  If the PMD does need to know this then a function to read and 
make adjustments needs to be added to the PMD functionality.  That also 
presupposes that there are signal lines to carry such administrative 
command information.  An alternative would be to make it a function of the 
MAC to be able to recognize the presence of the WIS and then signal the PMD 
via the MDC/MDIO.  Perhaps this has already been discussed and I missed it.

Thank you,
Roy Bynum

At 09:44 AM 10/30/00 -0800, Rich Taborek wrote:

>Rate Select could be used to select specific circuitry to allow both LAN
>and WAN line rate operation at a PMD. For example, the WAN PMD line rate
>is 10.000 Gbps the WAN PMD line rate is 9.952 Gbps. It may be necessary
>to switch in different oscillators, receive filters, etc. to enable a
>combinational physical embodiment of a LAN/WAN PMD.
>Architecturally for P802.3ae, rate select could be a bit in 10G PMA/PMD
>capability register 1.4 as described in Clause 33.
>Best Regards,
>Roy Bynum wrote:
> >
> > Schelto,
> >
> > For those of us that are unfamiliar with Fibre Channel optics, could you
> > explain what the "Rate Select" function is?
> >
> > Thank you,
> > Roy Bynum
> >
> > At 04:42 PM 10/28/00 -0700, schelto.vandoorn@xxxxxxxxxxxx wrote:
> >
> > >In the same sense as Rich did, I would like to throw in my 10 cents.
> > >
> > >Just as the link status needs to be defined, I see also the need to define
> > >two additional signals in the other direction.  Namely transmit disable
> > >and rate select.
> > >
> > >Rate Select
> > >This is also a new single on transceivers and in 10 GbE will be
> > >optional.  But I can see for some implementations that this signal could
> > >be useful to switch between different receive filters for different data
> > >rates, or different PMD's,  if they are implemented.
> > >
> > >I strongly believe that we should also define these signals.
> > >
> > >Have fun
> > >Schelto
>Richard Taborek Sr.                 Phone: 408-845-6102
>Chief Technology Officer             Cell: 408-832-3957
>nSerial Corporation                   Fax: 408-845-6114
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