Re: I/F locations
I agree, the two demarcations are XSBI and XAUI. SUPI is not an interface
as standardized by IEEE. Instead SUPI supports the 10GBASE-LW4 by attaching
WWDM to and XSBI interface. The 10GBASE-LW4 WWDM is supported attached to
XSBI using SUPI, while the 10GBASE-LR4 WWDM can only be supported by
implementing clause 48 and cannot attach to XSBI.
Though late for this discussion, it is possible to extend SUPI to allow
WWDM attachment to the LAN 64b/66b encoder over XSBI. This has three
advantages: 1)it means all optic modules and modes could be supported using
a XSBI interface; 2)the transmission frequency of the 10GBASE-LR4 would be
reduced from 3.125 MHz per lane to 2.578125 MHz per lane; 3)we end up with
a single 64b/66b PCS layer for all interfaces. Using this scheme XSBI could
support all optic module types. In addition, the XAUI option would also
support all types.
At 01:35 PM 12/1/2000 -0800, Speers, Ted wrote:
> I realize this is an implementation question, but is there a likely
>demarcation point between the transceiver module and the MAC. It's hard to
>sort out a lot of these discussions (LSS, XAUI/SUPI, etc.) without have this
>in proper context.
> Possible points of demarcation would seem to be either the XAUI or
>the XSBI interfaces. I've seen presentations suggesting both.
> It seems that a break at the XSBI would offer the most in terms of
>end-user flexibility and economies of scale for both the users and the
>vendors ... with one exception, 10GBASE-X4 would be left out in the cold
>because, as far as I can tell, there is no way to implement the standard
>across an XSBI.
> Ted Speers
> Strategic Marketing
Paul A. Bottorff, Director Switching Architecture
Enterprise Solutions Technology Center
Nortel Networks, Inc.
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Santa Clara, CA 95052-8185
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