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Re: Hari


- Hari has been proposed as a 10 GbE interface in Kauai. What exactly is your concern
with the process?
- Hari is not being proposed as a backplane interconnect 10 GbE. However, it is for
at least InfiniBand.
- Hari is the same as the Serial 10 GMII proposed by Howard Frazier of Cisco in
Montreal. I assume that this is what you mean by "XGMII". Why do you say that the
XGMII did not preclude the existence of other PHY's and Hari does?
- Hari can easily support a pacing mechanism. Would you like me to architect one for
- Which PHY do you believe is being "back doored" before the 802.3ae Task Force is in
place? Is it the LAN PHY? If this is the case I have to disagree on the grounds that
Hari is equally applicable as a PMA to PMD interface for 4 quite disparate LAN PMD
alternatives, 2 of those which may strip off the Hari 8B/10B code and apply a
significantly different and scrambled line code to a serial stream.
- The interface for which Hari is proposed may well we the only non-internal chip
interface in a mature 10 GbE products. As such, this interface is clearly one which
should be considered for standardization.

Best regards,


Roy Bynum wrote:

> Rich,
> I saw a lot of confusion in the presentations of what Hari is intended
> for.  One presentation used Hari as a backplane interconnect.  There is
> confusion on the reflector.  There IS a lot of "support" for Hari from
> vendors that want to stay on the good side of a particular vendor.
> Otherwise, I suspect that there is a lot of concern about the way that
> Hari has been brought to the HSSG.
> When Hari was first introduced at York, I thought that it was a proposal
> for a an XGMII.  While I did not actively support it, as a XGMII it did
> not preclude the existence of other PHYs.  It could be modified to
> incorporate a pacing mechanism between a PHY and the MAC.  The PHY would
> still implement the PCS/PMA/PMD for what ever standard the Task Force
> decided on, even the one from Korea.
> As far as I am concerned, any chip maker/system designer that wants to
> use Hari can.  I just don't want to see it standardized as the PCS to
> PMD interconnect, even as an optional.  The HSSG is not the correct
> forum to be doing implementation practices or standards.  That was one
> of the things that was impressed on me at the June meeting.  There is
> enough disparity between the PHYs to cause a major rift if a PHY
> implementation standard is decided on before the PHYs are even defined.
> Unless a particular vendor is doing their best to back door a PHY
> standard before the Task Force is even in place, there is no need to
> decide on implementation practices before the PHYs are fully defined.
> Thank you,
> Roy Bynum
> Rich Taborek wrote:
> > Roy,
> >
> > Multiple proposals aired in Kauai and I have already explained that
> > Hari is simply a "better" interface for attaching a MAC/PCS/PMA to a
> > PMD. As Dan Dove of HP has explained, Hari would at most be an
> > optional interface as was the case with both the TBI (closest Hari
> > equivalent in GbE) and GbE's GMII. Hari is a serial-based interface,
> > and as such requires a transmission code. 8B/10B was deemed to be the
> > best choice for Hari. That's it! I encourage you to propose a better
> > interface than Hari for its intended purpose or a better transmission
> > code for Hari. In the absence of either, I saw an awful lot of support
> > for Hari in Kauai and will continue to do my best to improve upon the
> > current proposal.


Richard Taborek Sr.   1441 Walnut Dr.   Campbell, CA 95008 USA
Tel: 408-330-0488 or 408-370-9233           Cell: 408-832-3957
Email: rtaborek@xxxxxxxxxx or rtaborek@xxxxxxxxxxxxx