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Re: Long distance links


The line coding for 100BaseFX is different from 1000BaseSX/LX, that did not prevent a
change.  Why should it prevent a change with 10000BaseXX?

Thank you,
Roy Bynum
MCI WorldCom

Dae Young KIM wrote:

> Rick,
> Please allow me add to your comments.
> Rich Taborek wrote:
> > However, there is no need for
> > any 802.3 activity to define such coexistence at 10 GbE Ethernet rates. Once the 10
> > GbE standard is set, many efficient implementations which route 10 GbE to SONET will
> > spring up.
> This is quite an interesting and appealing argument.
> > Paul's proposal specifically excludes most 10 GbE PHY proposals by requiring
> > specific encoding and delimiter usage to the point of requiring that the Ethernet
> > PHY = SONET OC-192 PHY. I don't believe that this is in the best interest of 802.3.
> I do also have some concern about the line of logics Paul has suggested.
> As far as I know MII data rate with concern to SONET is one thing and the Ethernet line
> coding is another.
> According to my understanding of Paul' picture:
>     MAC --(MII)-- 9.58Gbps --(backpressure)-- SONET Payload
>             -- Add SONET overhead -- SONET Line Coding(NRZ)
>             -- SONET line rate of 9.95Gbps
> OR
>     MAC --(MII)-- 10.0Gbps -- 10GbE PHY w/ line coding
>             -- 10GbE line rate(;depends on the line code chosen)
> As I understand, we're arguing on the MII rate which sits above the PHY layer. In that
> far, the decision on the line rate should not affect the choice of the 10Gbe PHY line
> code.
> --
> Regards,
> Dae Young