Re: Data rate standards vs internal switching standards
Roy,
Just a quick reappearance to address your follow up questions.
>
> I would like an additional clarification. In recognizing that the data
> clocking standards are at the exposed interface of the data link, does
> this mean that the standard applies to the MII between the MAC layer
> and the PHY or does it apply more to the PHY?
>
You have examples of both. The MII/GMII case is obvious.
Other exposed interfaces were defined within the PHY to reflect real
life partitioning into:
- Clock recovery being the realm of exotic circuits designed by long
haired gurus that seldom show up for work before 11 A.M.
- The coding layer, can go into CMOS based MAC ASICs, and can be
designed at any time of the day by many mortals skilled in the art of
digital design.
...
> As for the OC rate standard, there are several standards for mapping
> data into SONET/SDH transports. From an 802.3 view point, the
> SONET/SDH standards can be treated as layer 1 functional processes.
> From the other side of that argument, the current packet over SONET
> (POS) standard for mapping required an additional standard for
> inserting a layer 2 functionality between the layer 3 IP protocol and
> the layer 1 SONET protocol. 802.3 does not have that requirement for
> an additional functionality. In many ways it is more of a question of
> how much of the SONET/SDH standards would not used for 10GbE,
> depending on the implementation of the interfaces.
My emphasis was that the optimization of the data rate to 9.xyz is
specific for a particular mapping and cannot be adopted in isolation
unless such mapping is also embraced.
Finally, I hope that your lack of objection to a 10Gbps rate with a
statically programmable IPG is somehow a sign of agreement.
>
> Thank you,
> Roy Bynum
> MCI WorldCom
>
>
Regards,
Ariel Hendel
Sun Microsystems