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Re: Clause 48: Errors after T.



Stephen,
	You are missing something.  The XAUI interface occurs twice on the
link, and each time the reciever solves the problem.  Remember RD errors
can only happen on the XAUI electrical interface.

     MAC
     XGXS    Errors pushed into packet here!
     |  ^
     v  |
     XAUI electric
     |  ^
     v  |
     XGXS   Errors pushed into packets here!
     PCS

As you can see, regardless of the direction of the affected lane, and
XGXS will see the disparity error and push it into the packet if needed.

justin

Stephen.Finch@xxxxxx wrote:
> 
> I've been following this thread for awhile and I still don't get it.
> 
> I understand the "desire" to propogate a XAUI disparity error back into
> the packet in those cases where the error was after the T but still
> within "striking distance" of the data, i.e., within one XGMII transfer.
> 
> The method, as defined in the draft, will do this for 50% of the times
> it occurs.
> 
> YES, ONLY 50 % OF THE TIME.
> 
> The XAUI devices are between the MAC and the PCS.  All of the work we
> are doing fixes only those errors in the path from MAC -> XAUI -> PCS,
> but in the path PCS -> XAUI -> MAC, the same, exact, identical sequence
> of events that are detected and handled by the PCS will not be detected
> UNLESS THE MAC DETECTS IT.
> 
> Now, if the MAC must detect it for the second case, why not let it
> detect it for the first case as well, and remove the REDUNDANT LOGIC
> from the PCS?
> 
> Is there an error in my thought process?
> 
> I've been (quietly) against the inclusion of this since I joined
> 802.3ae, but being a new comer I assumed I was missing something.
> 
> Regards,
> 
> Stephen Finch

-- 
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:   www.rocketchips.com
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