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RE: XAUI/XGXS Question




OK, Thx., Its clear now.


> -----Original Message-----
> From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
> Sent: Monday, May 15, 2000 6:57 PM
> To: HSSG
> Subject: 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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