Re: (Another) Question Regarding Open-Loop Control Mechanism
Boaz, et. al.
The baseline proposals, as written today support door #1. That is:
The minimum IPG at the transmitter is 9 bytes and the minimum IPG at the
receiver is 5 bytes.
Idles can be removed at the encoded or decoded data level. The rule
above is supportable by 8B/10B and 64B/66B encoding. The only question
is whether the MAC can deal with a 5 byte IPG every once in a while.
Note that the "average" IPG at the transmitter and receiver would still
be around 12.
Alternatively, if the MAC can't handle a 5 byte IPG, the rule can be
changed to door #2:
The minimum IPG at the transmitter is 9 bytes and the minimum IPG at the
receiver is 9 bytes.
This would work as well since the average IPG at the transmitter is
still 12. Elasticity buffering requirements would need to be increased
to allow a longer wait for a deletable idle.
Best Regards,
Rich
--
Boaz Shahar wrote:
>
> Pat,
>
> > get as short as 9 bytes. I believe it would be possible to write the
> > standard so the gap is never allowed to shrink below that or
> > to allow it to
> > shrink to something smaller.
> >
>
> The standard has to refer to two parameters regarding the size of IPG: 1)
> The minimum size of IPG during transmission (i.e. while packet is output
> from the MAC). 2.The minimum size of IPG during reception (i.e. when it goes
> to the receptor MAC).
>
> I think that the last discussion leads to the conclusions that:
>
> 1.They cannot be equal. If they do, you cannot do clock tolerance
> compensation
> 2.As bigger the difference between Min IPG size (Tx) to MIN IPG size (Rx) -
> System reliability in terms of clock tolerance immunity is better
>
> We may choose one of two options:
>
> 1.Either say that MIN IPG during Tx is 9-12 (As is today), and during Rx is
> 5-8, and allow any unit at the middle to remove /R/ column
> 2.Or go back to the original proposals with MIN Tx IPG 13-16 (/A/, /K/, /R/)
> and 9-12 during reception, an allow any unit to remove an /R/ column
>
> Boaz
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