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Re: Interface reality check


Great work! I applaud your efforts.

Best Regards,

Rick Walker wrote:
> Dear Mike,
> > Mike Jenkins <jenkins@xxxxxxxx> writes:
> > I applaud your rigorous standards expressed below (especially liked
> > the analogy about cleaning up campsites), but I want to draw one
> > distinction regarding control codes.  The ordered set control code(s)
> > (/O/) is (are) needed to transmit Fibre Channel traffic, not solely to
> > enable XAUI.  The needs of byte vs. word striping may vary, but that's
> > another issue.  Ordered sets (K28.5, Dxx.x, Dxx.x, Dxx.x) are a
> > necessary part of Fibre Channel, as much as SOP, EOP, etc., are for
> > Ethernet.  (Since it's just K28.5, I admit I'm not sure whether it's
> > extra control codes or just more frame types that are needed.)
> I agree with you completely.
> I fully support any mechanisms that are rationally agreed upon after
> the standardization process.
> > I realize that encompassing FC was not part of your original objective
> > but use of 64b/66b code is being discussed here in the FC plenary
> > sessions.  I think we need to know soon if this code will or won't
> > accommodate Fibre Channel.
> Some people have questioned the idea of not allowing "code leakage".
> Supporting /O/ characters is quite reasonable and completely independent
> of the "code leakage" issue.
> The 64b/66b codec will almost certainly be a superset of whatever 10 GbE
> actually standardizes.  This is similar to the existing case with
> 8b/10b and 1GbE.  I certainly didn't want to imply that I am against
> supporting a rich set of control codes.  My point is really about the
> process of standardizing code usage - not about crippling the code by
> removing functionality.
> That aside, I am working very hard to extend 64b/66b to support FC.  Using
> Information from Osamu Ishida and Rich Taborek, we believe that we should
> support four distinct kinds of /O/ characters. Quoting from Osamu:
>     A) Interoperable XGENIE ordered sets,
>     B) Fibre Channel ordered sets,
>     C) Carrier Specific ordered sets (used in customized option chip),
>     D) Vendor Specific ordered sets.
> I have developed a proposal to support all four kinds of ordered
> sets for all the following frame types:
>     1) ZZZZ/ODDD
>     2) ODDD/ZZZZ
>     3) ODDD/ODDD
>     4) ODDD/SDDD
> The penalty for doing this was that the hamming distance for control
> symbols fell from 4 to 3. However, the TYPE bytes which determine
> Ethernet packet boundaries are still 4-bit strong.
> I believe this expanded code space will amply support Fiber Channel and any
> possible extensions that we may or may not decide to standardize within
> 10 GbE.
> I am not too worried about the reduction in control space hamming distance,
> as the 3 bit distance is already better than the 8b/10b control space
> hamming distance.
> Best regards,
> --
> Rick Walker
Richard Taborek Sr.                 Phone: 408-845-6102       
Chief Technology Officer             Cell: 408-832-3957
nSerial Corporation                   Fax: 408-845-6114
2500-5 Augustine Dr.        mailto:rtaborek@xxxxxxxxxxx
Santa Clara, CA 95054