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RE: Clause 49 /A/ /K/ /R/ on XGMII question

When there is no error on the XAUI, ||A||, ||K|| and ||R|| are translated by
the XGXS to a column of /I/ on the XGMII. I think that it is simpler to do
the same when an error occures in one of the bytes of such a column, except
that the specific erronous byte has to be translated to /E/ on the XGMII.

In the case of 10GBASE-R, the erronous byte is handled like /E/ and the rest
like /I/ on the XGMII.


> -----Original Message-----
> From: pat_thaler@xxxxxxxxxxx [mailto:pat_thaler@xxxxxxxxxxx]
> Sent: Thursday, February 15, 2001 12:52 AM
> To: jgaither@xxxxxxxxxxxxxxx; stds-802-3-hssg@xxxxxxxx
> Subject: RE: Clause 49 /A/ /K/ /R/ on XGMII question
> Justin,
> The XGXS only converts /A/, /K/, and /R/ to /I/ when they 
> occur in a whole
> column: an ||A||, ||K||, or ||R|| ordered set. Therefore, one 
> type of error
> that would cause /A/, /K/, or /R/ on the XGMII output from an 
> XGXS would be
> a bit error that changed the value of one or more bytes in an 
> ordered set.
> If such an error happens, there is no particular reason for a 
> to change the remaining /A/, /K/ and /R/ symbols to an /E/. 
> We have code
> table entries for them and replacing them with something else would
> complicate implementation.
> The primary purposes of sending an /E/ are: 
>   to avoid changing an unencodeable input into something that 
> might produce
> an undetectable error. 
>   to propogate special error detection that preserves 
> delimiter Hamming
> distance so that code dependent 0- to 3-bit errors don't produce
> undetectable errors.
> Neither of those purposes would be served by changing a 
> spurious /A/, /K/ or
> /R/ into an /E/. Furthermore, the RS has to handle receiving 
> these /A/, /K/
> and /R/ code groups because an XGXS might be directly 
> connected to the RS.
> If one believes that /A/, /K/ and /R/ should not be allowed 
> to exist at the
> XGMII interface, than it is the 10GBASE-X/XGXS coding rules 
> that should be
> changed and not 10GBASE-R.
> Regards,
> Pat 
> -----Original Message-----
> From: Justin Gaither [mailto:jgaither@xxxxxxxxxxxxxxx]
> Sent: Wednesday, February 14, 2001 11:29 AM
> To: 802.3ae
> Subject: Clause 49 /A/ /K/ /R/ on XGMII question
> Hello,
> 	Page 345 line 30-31 says "The codes for /A/ /K/ and /R/ 
> are used on
> the
> XAUI interface to signal idle.  They are not present on the XGMII when
> no errorrs have occurred, but certain bit errors cause the 
> XGXS to send
> them on the XGMII."
> What types of errors would this be? and why would we want 
> allow them to
> continue through the 10GBase-R, into the optional WIS and 
> onto the link?
> Should these be replaced by /E/?
> -- 
> Justin Gaither                       Phone: 512-306-7292  x529
> RocketChips a Division of Xilinx     Fax:   512-306-7293
> 500 N. Capital of TX Hwy.
> Bldg 3                         email: jgaither@xxxxxxxxxxxxxxx
> Austin, TX 78746               WWW: