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Re: Roy's thread


I agree. The 16 bit OIF (or TBI) interface is the simplest universal PMD
interface. It has a place even when Hari exists. 



At 01:47 PM 11/22/99 -0800, Bill Woodruff wrote:
>Roy & others,
>If we want to do a simple serial PHY, then we need a simple parallel
interface.  An OIF style x16 interface is good, as would be a TBI (ten bit
interface).  In either case we have a parallel word with clock.  While this
is simple, it has two issues that the Hari interface avoids; the high pin
count and the tight skew requirments.  
>Just because Hari exists does not make the simple x16 or x10 interface go
away.  Chips and modules with these interfaces either do, or can, exist,
and equipment people can easily use them.
>Meanwhile the Hari world may also want a simple Hari repeater.  Such a
device would be a simple 'eye opener' for a media that retains the 4
channels as independent.  Such a repeater opens the discussion of Hari as a
PHY interface, which up till now has not been well discussed.
>Regards, Bill
>I'm not sure what gave you the idea that Hari was favorable to serial
PHYs.  I do know that
>it is not favorable to anything other than the legacy fiber channel 8B10B
LAN PHY.  Hari is
>NOT a PHY neutral device interconnect.  Some LAN vendors have very huge
boards and they want
>something that will support their 8B10B encoding over the distance of
their board, and also
>the back plane if needed.  By introducing Hari as the standard for device
>between the PMA and the PMD,  they are specifically, and possibly
knowingly, hampering the
>development of the agreed on WAN PHY.  There is no mechanism for rate
controlling over
>Hari.  This is in violation of the agreed objective in this regard.  Hari
is an attempt by a
>specific camp to control the development of 10GbE and limit development of
anything other
>than the 10.0 only rate PHY.
>As you will remember, I called the presenters and floor on the issue of
what Hari really
>was.  It was admitted that it was a LAN extension interconnect by the
individual that
>responded.  For those of us that are attempting to bring 802.3 into the
20th century by
>making a truly ubiquitous MAC, we have been astounded by the brazen push
of this
>"interconnect".   Chip makers will confirm that Hari specifically makes
>extremely difficult to implement.  Since Hari truly is not common to all
of the PHYs as
>specified in the objectives, I suggest that it be withdrawn from
consideration as part of
>the 10GbE standard.
>Thank you,
>Roy Bynum
>Bill Woodruff				ph: 805 496-7181 x14
>GiGA North America Inc.		fax: 805 496-7507
>299 W. Hillcrest Dr., Suite 206		woodruff@xxxxxxxxxxx
>Thousand Oaks, CA  91360
>See us at 00OFC in Baltimore, March 7-9 2000, Booth 2450
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@xxxxxxxxxxxxxxxxxx