Re: XAUI/XGXS Question
Boaz,
Yes. The deskew "marker" spacing needs to be at least 2 times wider than the
maximum skew. 2 x 39 = 78; 78 < 80; 160 is used. I thought that you had
understood this in one of your previous statements:
> If MaxSkew=40 Bits and all /R/ columns are removed, then the
> size of the IPG is 8 characters (=80 bits) which is exactly
> twice the skew. In this case, there is ambiguity.
That only goes to prove that the reflector is far from the best means of
communication :-)
Best Regards,
Rich
--
Boaz Shahar wrote:
>
> OK, but there, in page 16 you wrote:
> "40 UI deskew pattern neds to be 80 bits". I probably did not understand it
> well. Can you help with that?
> Thx.,
> Boaz
>
> > -----Original Message-----
> > From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
> > Sent: Monday, May 15, 2000 9:23 AM
> > To: HSSG
> > Subject: Re: XAUI/XGXS Question
> >
> > Boaz,
> >
> > The 39 bit maximum skew figure is deemed to be worst case and
> > is already less than 1/4 the Align code-group (/A/) spacing.
> >
> > Skip column processing for an Ethernet link including two
> > XAUI may result in the removal of two /R/ columns, reducing
> > /A/ spacing to 140 bits. The same removal would not be
> > required again for more than 13 maximum sized frames.
> >
> > In summary, a 160-bit spacing is overkill and more than
> > adequate. There is no reason to increase the minimum /A/ spacing.
> >
> > Best Regards,
> > Rich
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