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RE: RS minimum IPG




It occurs to me that one source of confusion may be on how to count the IPG.
The IPG includes the /T/. A minimum IPG of 5 characters is a /T/ plus 4
/I/s.
Currently, clause 49 states that the minimum is 5 /I/s but I have submitted
a comment to change that to 4.

10GBASE-R requires that minimum IPG for encoding. With an IPG of 5, a start
and terminate never fall within the same block. 

10GBASE-X requires that minimum for disparity checking. The check_end
function returns an error if the column after the ||T|| is neither ||A|| nor
||K||.

Regards,
Pat

-----Original Message-----
From: THALER,PAT (A-Roseville,ex1) 
Sent: Tuesday, February 20, 2001 9:48 AM
To: 'Sanjeev Mahalawat'; stds-802-3-hssg@ieee.org; yariv@galileo.co.il
Subject: RE: RS minimum IPG


Sanjeev,

Where do you find such a definition in the standard? I don't know of
anyplace a minimum receive IPG of 5 is stated. Further, that is a parameter
that has varied based on speed so what it was at 100/1000 Mb/s does not
limit our choice at 10 Gig. 

Regards,
Pat  

-----Original Message-----
From: Sanjeev Mahalawat [mailto:sanjeev@cisco.com]
Sent: Monday, February 19, 2001 11:25 AM
To: stds-802-3-hssg@ieee.org; yariv@galileo.co.il
Subject: Re: RS minimum IPG



The min IPG varies from 9 bytes to 15 bytes
based on the packet size and due to clock compensation
the PHY may delete a column that will lead to min
IPG of 5 Bytes. So, thoeritically it should not be
less than 5 bytes but the spec. always defines it
to be 4 bytes as this was in the 100/1000 mbps
specs.

Thanks
-Sanjeev