Re: I/F locations
Rich:
I didn't intend to imply that XSBI was required. It is an optional
interface for 10GBASE-LW4.
Rich, I believe some or us would like to build systems using XSBI
interfaces. It is inconvenient
that 10GBASE-LR4 is unsupported using XSBI.
Rich, the current SUPI implementation does not support LAN mode in the
UNIPHY, however this
could easily change by adding a periodic A1/A2 sequence to the 64b/66b data
stream. It would
only be necessary to add 8 A1 octets and 8 A2 octets. The current clause 53
operation can then
operate without modification. This would be nice since it makes the UniPHY
really unified around
the provided electrical interfaces.
Cheers,
Paul
At 09:38 PM 12/1/2000 -0800, Rich Taborek wrote:
>Paul,
>
>I have to respectfully disagree that the XSBI is in any way a required
>interface of the 10GBASE-LW4 PHY. As you clearly indicate in D2.0,
>Clause 53, Figure 53-1, the XSBI is an optional interface for the
>10GBASE-LW4 PHY. Figure 53-1 clearly illustrates that the WIS may be
>directly attached to the LW4 PMA.
>
>I don't understand your point of suggesting the extraneous insertion of
>a high pin count, extraneous parallel interface (the XSBI) into the
>10GBASE-LR4 PHY. Is there some specific benefit or purpose of this
>suggestion?
>
>I am very confused by your second paragraph where you mention as SUPI
>"extension" to allow WWDM attachment to the LAN 64b/66b encoder over
>XSBI.
>
>1) All of the aforementioned elements, with the exception of the XSBI,
>are required for the 10GBASE-LW4 PHY;
>
>2) SUPI is a PMA which is only applicable to the 10GBASE-LW4 PHY. It is
>not applicable to either the 10GBASE-LR4, 10GBASE-XR, or 10GBASE-XW
>PHYs.
>
>Here are my specific questions:
>
>A) What is a SUPI extension?
>
>B) How does a SUPI extension enable the use of the XSBI to "all optical
>modules"?
>
>C) How would the XSBI be used as an optical interface for the
>10GBASE-LR4 PHY? Do you have a proposal to do this?
>
>D) What is the advantage of using the 64b/66b PCS for the 10GBASE-LR4
>PHY? Do you have a proposal to do this?
>
>E) What specification/Clause specifies SUPI electrical operation,
>specifically the channel model, jitter budgets, transmit eye and receive
>eye? I am not aware that this is covered by any clause including Clause
>47. In essence, the lower line rate advantage of SUPI is offset by
>undesirable characteristics which significantly increase jitter such as
>very long and unpredictable run lengths. It appears that no such
>specifications exist.
>
>Best Regards,
>Rich
>
>--
>
>Paul Bottorff wrote:
> >
> > Ted:
> >
> > I agree, the two demarcations are XSBI and XAUI. SUPI is not an interface
> > as standardized by IEEE. Instead SUPI supports the 10GBASE-LW4 by attaching
> > WWDM to and XSBI interface. The 10GBASE-LW4 WWDM is supported attached to
> > XSBI using SUPI, while the 10GBASE-LR4 WWDM can only be supported by
> > implementing clause 48 and cannot attach to XSBI.
> >
> > Though late for this discussion, it is possible to extend SUPI to allow
> > WWDM attachment to the LAN 64b/66b encoder over XSBI. This has three
> > advantages: 1)it means all optic modules and modes could be supported using
> > a XSBI interface; 2)the transmission frequency of the 10GBASE-LR4 would be
> > reduced from 3.125 MHz per lane to 2.578125 MHz per lane; 3)we end up with
> > a single 64b/66b PCS layer for all interfaces. Using this scheme XSBI could
> > support all optic module types. In addition, the XAUI option would also
> > support all types.
> >
> > Cheers,
> >
> > Paul
> >
> > At 01:35 PM 12/1/2000 -0800, Speers, Ted wrote:
> >
> > > I realize this is an implementation question, but is there a
> likely
> > >demarcation point between the transceiver module and the MAC. It's
> hard to
> > >sort out a lot of these discussions (LSS, XAUI/SUPI, etc.) without
> have this
> > >in proper context.
> > >
> > > Possible points of demarcation would seem to be either the
> XAUI or
> > >the XSBI interfaces. I've seen presentations suggesting both.
> > >
> > > It seems that a break at the XSBI would offer the most in
> terms of
> > >end-user flexibility and economies of scale for both the users and the
> > >vendors ... with one exception, 10GBASE-X4 would be left out in the cold
> > >because, as far as I can tell, there is no way to implement the standard
> > >across an XSBI.
> > >
> > > Ted Speers
> > > Strategic Marketing
> > > Actel
> >
> > Paul A. Bottorff, Director Switching Architecture
> > Enterprise Solutions Technology Center
> > Nortel Networks, Inc.
> > 4401 Great America Parkway
> > Santa Clara, CA 95052-8185
> > Tel: 408 495 3365 Fax: 408 495 1299 ESN: 265 3365
> > email: pbottorf@NortelNetworks.com
>
>-------------------------------------------------------
>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@nSerial.com
>Santa Clara, CA 95054 http://www.nSerial.com
Paul A. Bottorff, Director Switching Architecture
Enterprise Solutions Technology Center
Nortel Networks, Inc.
4401 Great America Parkway
Santa Clara, CA 95052-8185
Tel: 408 495 3365 Fax: 408 495 1299 ESN: 265 3365
email: pbottorf@NortelNetworks.com