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Re: Link Status encodings


I called the Ordered-Set Pulse instead of Link Status because Link
Status represents only the two messages defined for transport, namely
Local Fault and Remote Fault. A third message Break Link, is proposed
but not accepted. It is not a Link Status, but rather a Link Request. In
the future 10GE may have a use for Pulse Ordered-Sets for some reason
perhaps having nothing to go with Link Status. I wanted to chose a
generic name to prevent a potential future naming conflict.

As far a running disparity goes, I see a potential desire for 10GE
implementations to replace an ||R|| with a ||P|| at the 10b level. This
would not be possible if I chose a non-neutral disparity special
code-group for the /K/ of ||P||. All data code-groups associated with
||P|| would need to observe the same rules. However, we're quickly using
up the 12 special code-groups and the /D/ codes are much easier to
change down the line if required. Yes, it's half-baked, but it provides
flexibility and affects nothing. You are 100% correct none of this
discussion is applicable to ||P|| inserted at the 8b level.

In November a liaison letter was forwarded from the chair of NCITS T11
to the chair of IEEE P802.3ae requesting cooperation between 10GFC and
P802.3ae efforts. One of the proposals I will be making to P802.3ae is
the reservation of certain codes for 10GFC usage. This applies to the
10GFC Signal and Sequence Ordered-Sets. 

Best Regards,

"Bharadwaj S. Amrutur" wrote:
> Rich,
> Pulse ordered sets - is semantically extremely confusing.
> I would prefer the simpler  LS : Link status
> You mention a desire to keep the running disparity of the D octets
> in the K/D/D/D  0. If we make sure that the LS code is inserted
> prior to  XAUI encoding and deleted after XAUI decoding,
> running disparity shouldn't be a problem, right?
> You also mention a new ordered set K28.6/D/D/D and its translation into
> 0x0101 for 64/66. Was this proposed in the November plenary?
> regards
> Birdy
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