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RE: 64/66 control code mapping

I am in complete agreement with Brad here.

In Gigabit Ethernet, the PCS was defined in terms of the GMII, which was an
optional interface. In our objectives, we have defined a requirement to
create a 10 gig MII (XGMII) as an optional interface. From the perspective
of convention, we can argue that it is completely reasonable to define the
10 Gig PCS or PCS's in terms of the XGMII. We could also argue that it would
be appropriate to define the 10 Gig PCS or PCS's in terms of the optional
XAUI interface. But, I believe that we should discourage this approach. I
believe that it would simplify the overall structure of the document and
reduce the amount of work we have to do if we clone the same approach used
in previous versions of the standard to the greatest degree possible.

This should in no way impact optimization of practicle implementations,
which may choose to not implement the XGMII.


> -----Original Message-----
> From: owner-stds-802-3-hssg-64b66b@xxxxxxxx
> [mailto:owner-stds-802-3-hssg-64b66b@xxxxxxxx]On Behalf Of Booth,
> Bradley
> Sent: Sunday, March 12, 2000 10:44 AM
> To: stds-802-3-hssg-64B66B@xxxxxxxx
> Subject: RE: 64/66 control code mapping
> I would agree that we have to be careful in how we think of XAUI,
> XGMII and
> 64/66 encoding.  In the standard, XAUI and XGMII may be optional
> instantiations of service interfaces.  XAUI being an instantiation of the
> XGXS service interface.  XGMII being an instantiation of the PCS service
> interface.
> As of yet, the Task Force hasn't decided what those service
> interfaces look
> like, but I think it would be fair to assume that the PCS service
> interface
> is a 32 bit data interface and the XGXS service interface is a 4 pair
> differential interface (one direction only of course).  If that is that
> case, then the 64/66 proposal should be based on the 32 bit data
> PCS service
> interface, rather than the XGXS service interface.
> If the 64/66 proposal could show how it is implemented using a XGMII and a
> XAUI, then I think that would help show a PCS service interface
> implementation and a XGXS service interface implementation.  The XGMII
> implementation would be closer to being a true PCS proposal.
> Thanks,
> Brad

The rest cut.... jt