RE: 10G-BASE-T question (dd1)

["Grow, Bob" <bob.grow@xxxxxxxxx>]

Dan:

I don't share your primary concern (at least in perceived magnitude). An
8-bit interface is already included in the standard (GMII), all that need
change is the clock rate (not something subject to discriminatory
licensing).  A wider interface presents more constraints, and if wanted as
an option must be used in evaluating a number of the PHY proposals. (A wider
interface can affect preamble, IPG, and latency at a minimum.)

--Bob Grow


-----Original Message-----
From: Dan Dove [mailto:dan_dove@xxxxxx]
Sent: Tuesday, June 08, 1999 9:22 AM
To: stds-802-3-hssg@xxxxxxxx
Subject: Re: 10G-BASE-T question (dd1)



Hi Jaime,

Actually, I would be happy if we architected a solution that allowed us
to set the width/clock-rate at initialization. This way, we could use
a 32 bit wide implementation in early implementations, and possibly an
8 bit wide implementation later. Whether this is a hard configuration or
negotiable via MDIO/MDC is negotiable.

My primary concern is that we not standardize an obsolete technology
that ends up being superceded by a proprietary implementation that
does not have the rigorous design, or non-discriminatory licensing of
an IEEE standard.

I believe a small amount of foresight in the development of this 
standard will save us a lot of pain in the future.

Best Regards,

Dan Dove

-- 
___________     _________________________________________________________
_________    _/    ___________  Daniel Dove         Principal Engineer __
_______     _/        ________  dan_dove@xxxxxx     LAN PHY Technology __
_____      _/           ______  Hewlett-Packard Company                __
____      _/_/_/ _/_/_/  _____  Workgroup Networks Division            __
____     _/  _/ _/  _/   _____  8000 Foothills Blvd. MS 5555           __
_____   _/  _/ _/_/_/   ______  Roseville, CA 95747-5555               __
______        _/      ________  Phone: 916 785 4187                    __
_______      _/      _________  Fax  : 916 785 1815                    __
__________  _/ __________________________________________________________

kardontchik.jaime@xxxxxxxxxxx wrote:
> 
> Rogers,
> 
> The figure on page 4 emphasizes more the maximum clock used in the
> 10G-BASE-T architecture, 1.25 GHz, and the maximum baud rate
> in the optical fiber, 1.25 Gbaud/sec.
> 
> The actual width of the MII interface is a question open to discussion.
> 
> Shimon Muller (Sun) suggested using a 32-bit wide interface (64-bit
> wide if we include both the Tx and Rx). Dan Dove (HP), in the audience,
> suggested that if we use a 32-bit wide interface we might end up with
> a chip that is all I/Os surrounding a tiny design, and he suggested to
> take here an agressive approach and stick to an 8-bit wide interface.
> 
> I tend to agree with Dan for the same reason and for another one:
> 32 TTL-type output drivers at the Rx would introduce a lot of
> switching noise that could affect the analog blocks in the chip,
> including the jitter of the transmitter.
> 
> Jaime
> 
> Jaime E. Kardontchik
> Micro Linear
> San Jose, CA 95131
> email: kardontchik.jaime@xxxxxxxxxxx
> 
> "Rogers, Shawn" wrote:
> 
> > Jaime, I have a question concerning your presentation in Idaho.  On page
4
> > of your presentation you state the following when comparing your
10G-Base-T
> > proposal to 802.3ab (1000Base-T):
> >
> >    1000Base-T           10G-Base-T
> >     GMII-8bit wide      10GMII - same
> >
> > Are you advocating a byte wide chip-to-chip interface between the PCS
and
> > Reconciliation sublayer in the MAC running at 1.25Ghz?
> >
> > Regards,
> > Shawn
> >
> > -----Original Message-----
> > From: Jaime Kardontchik [mailto:kardontchik.jaime@xxxxxxxxxxx]
> > Sent: Monday, June 07, 1999 5:57 PM
> > To: stds-802-3-hssg@xxxxxxxx
> > Subject: 10G-BASE-T presentation
> >
> > Hello 10G'ers,
> >
> > For those that were not able to attend the Idaho meeting:
> >
> > The presentation on the 10G-BASE-T architecture given
> > in Idaho included more material than the original posted
> > two weeks ago.
> >
> > The updated presentation as given in Idaho is now in the
> > web site,  replacing the old one:
> >
> > http://grouper.ieee.org/groups/802/3/10G_study/public/june99
> >
> > Jaime
> >
> > Jaime E. Kardontchik
> > Micro Linear
> > San Jose, CA 95131
> > email: kardontchik.jaime@xxxxxxxxxxx