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RE: XGMII a/k/r and XGXS - PCS Interface

Title: RE: XGMII a/k/r and XGXS - PCS Interface


You are right about the multiple stage lookahead in the 1000BASEX PCS,
it was called the crystal ball, and was used for looking for 3 symbol
end-of-packet delimiters, /T//R//R/, /T/,/R//K28.5/ etc. So your
suggestion could be a good way to solve this residual error case.


-----Original Message-----
From: Tom Mathey [mailto:tmathey@xxxxxxxxxxxxxx]
Sent: 11 April 2000 10:26
To: Una Quinlan; stds-802-3-hssg@xxxxxxxx
Subject: RE: XGMII a/k/r and XGXS - PCS Interface

Una Quinlan

For the case you described of: 

        (c) EOP Case (with 2 residual bytes):   /E/ /D/ /T/ /K/ /R/ /R/ /R/ /R/. How could this be encoded? It may not be       possible to adopt an approach like the SOP case, where an Error codeword        is transmitted, and a delayed EOP indication follos. Because this would         eat into the IPG by up to 7 bytes.

one possible solution is to have a multiple stage delay from input to output such that
the error can be detected and then change the data that is at the output of the delay just
before it is shipped on out to the next layer.

My memory tells me that someplace in 802.3z (1Gig) there was a multiple stage delay
on receive before a packet was delivered to the RS/MAC.

Tom Mathey