RE: Short haul PMDs
I would add to your point that much of the anecdotal conversation that I
have actaullay heard over the years since "z" has been that to NOT use CX
for short haul but rather use 1000BASE-T in that application space on the
assumption that 1000BASE-T was going to be a "volume" product where CX
presumably was not. I always assumed that folks were believing that
1000BASE-T would make significant volume in the 100m in-the-wall
application space. That is an assertion that has not been realized to date.
The cross effect of CX on 1000BASE-T and vice versa is something that
should be included in the conversation when/if we reopen the objectives for
short-haul and talk about broad market potential and economic feasibility.
At 10:33 AM 8/7/00 -0600, pat_thaler@xxxxxxxxxxx wrote:
>Perhaps I did not make myself clear enough. Much of the short haul
>discussion has been about links much shorter than 100 m. 1000BASE-T
>reaches 100 m. The question was what 1000BASE-CX numbers look like.
>From: Marshall Eisenberg [mailto:marshall@xxxxxxxxxxxxxx]
>Sent: Friday, August 04, 2000 6:45 PM
>To: Seto, Koichiro; pat_thaler@xxxxxxxxxxx; gthompso@xxxxxxxxxxxxxxxxxx;
>Subject: RE: Short haul PMDs
>According to Dell'Oro's numbers, about 8,000 1000Base-T networking ports
>shipped in Q1/00. The Q2/00 numbers should be out soon.
>[mailto:owner-stds-802-3-hssg@xxxxxxxx]On Behalf Of Seto, Koichiro
>Sent: Thursday, August 03, 2000 4:58 PM
>To: pat_thaler@xxxxxxxxxxx; gthompso@xxxxxxxxxxxxxxxxxx; hakimi@xxxxxxxxxx
>Subject: Re: Short haul PMDs
>[Date: 08/03/2000 From Seto]
>Maybe, HP pro-curve unit has... They are the one of a few vendors actually
>shipping 1000BASE-CX options I believe.
> > So, does anyone have data on what percentage of Gigabit Ethernet links
> > ship with 1000BASE-CX?
> > Pat
> > -----Original Message-----
> > From: Geoff Thompson [mailto:gthompso@xxxxxxxxxxxxxxxxxx]
> > Sent: Wednesday, August 02, 2000 4:45 PM
> > To: Hakimi, Sharam (Sharam)
> > Cc: stds-802-3-hssg
> > Subject: RE: Short haul PMDs
> > Sharam-
> > I think 15 years is a slight exaggeration. 10BASE-T started as a Study
> > Group in August of 1987. It was the first group to have a 100 meter
> > objective.
> > Before 10BASE-T there was the following:
> > 10BASE5 + AUI The AUI cable was 50 meters max
> > 10BASE2 The coax was daisy-chained w/ an overall max of 185m
> > 1BASE5 (StarLAN) The hub to DTE distance was 250 m
> > 10BROAD36 Broadband diameter of 2800 meters
> > FOIRL 1000 meter links
> > The point here is that topology has evolved as well as speed.
> > We have in the recent past had a distance objective for short cables in
> > 802.3z (ref: 1000BASE-CX).
> > The 100 meter distance history is rooted in facilities cabling and is
> > on the (literally) cast-in-concrete distance of 90 m max from the cabling
> > closet to the telecommunications outlet.
> > If the prime market for an Ethernet project is not oriented to
> > "in-the-wall" cabling then the 100 meter distance is not sacrosanct. The
> > objective for 100 meters as approved in York was for "installed" cabling
> > from ISO/IEC 11801. That means that we were talking about generic
> > facilities cabling at the time, not application specific cabling.
> > If we do go to application specific cabling then we have to do the
> > specification in our own standard instead of referencing an outside
> > standard such as ISO/IEC 11801.
> > Geoff
> > At 11:16 AM 8/2/00 -0400, Hakimi, Sharam (Sharam) wrote:
> > >During the past 15 years and through all of 802.3 distance Objectives,
> > >meters has been the minimum and essentially the trademark of IEEE 802.3.
> > >There has always been discussions that if the distance is reduced we can
> > >provide less expensive PHYs, but the cost difference never justified
> > >development of these PHYs . Providing 100 meter solutions does not
> > >anyone from using a 10, 20, 30 or other length cables as their needs
> > >require. However, if time has come that the cost difference between a 100
> > >meter solution and something less will justify such development then we
> > >could look at it later, but changing the objectives at this time is a BAD
> > >idea in my opinion.
> > >
> > >Sharam Hakimi