Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: PCS Tx Diagram (Clause 48)

Boaz Shahar wrote:
> Rich,
> > Qualification by A_CNT_0 is required to insure that ||A|| is
> > sent with aminimum spacing. In the case of a short normal or
> > erred packet, A_CNT_0 qualification prevents the issuance of
> > ||A|| with less than the minimum required spacing.
> Two points:
> 1.Normal short packet is 72 bytes include preamble. This is 18 columns which
> is more than the mimimum spacing anyway.

I misspoke when I said "minimum" spacing. I should have said random
||A|| spacing. Furthermore, the PCS Idle sequence protocol must also
account for unusual events such as packets which terminate early (e.g.
packets less than 72 bytes in length).
> 2.The MAC starts to transmit packets only after de dkewing completion in the
> other side. After de skewing completion, you do not need the minimum spacing
> any more. So in a case of erronous frame, I see no problem.

MAC packet transmission is only partially dependent of the state of
deskew at the remote device. In any case, minimum ||A|| spacing the
transmitter is ALWAYS required since the remote link end may go out of
sync an may invoke the deskew process at any time. 

> > That path covers the case of the anything other than Idle coming over
> > the XGMII/RS. It will be sent as is.
> So an IDLE pattern composed of first /K/ column and then something from the
> MAC is acceptable?

I didn't say it came from the MAC. I said it came over the XGMII/RS. How
it got there is anyone's guess. In any case, the 10GBASE-X PCS must
handle it.

> > Yes. This is correct. SIGNAL may occur anytime. Please note
> > that SIGNAL and SEQUENCE are not part of the P802.3ae Baseline
> > proposal set and I included then for two purposes:
> >
> > 1) Show how these 10 Gigabit Fibre Channel Ordered-Sets operate and
> > interact with all 10GE Ordered-Sets. A 10GFC liaison request
> > is to only reserve 10GE code space for these Ordered-Sets but not
> > include them in P802.3ae state diagrams.
> >
> > 2) Show how these Ordered-Sets may be used to transport Link Status
> > information per taborek_2_1100.pdf
> I see. As a matter of fact it is interesting. Can you provide an
> explanation/pointer for FC operation?

10GFC Baseline Proposal Set -
10GFC Project Report -
10GFC draft 0.1 -

> I see. So: Any decisions made in Tampa regarding the LSS?


> Thx.,
> Boaz


Best Regards,
Richard Taborek Sr.                 Phone: 408-845-6102       
Chief Technology Officer             Cell: 408-832-3957
nSerial Corporation                   Fax: 408-845-6114
2500-5 Augustine Dr.
Santa Clara, CA 95054