Re: Signal vs. Idle debate (was: Here's a new idea)
Mike,
You wrote
"Of the power schemes that have been proposed, only the idle pair proposals have
addressed preserving the investment of all of the current 802.3 users by
allowing mid-span power insertion. While the signal pair camp may claim they
are preserving the wiring infrastructure of a proportion of the of the 802.3
users ignored by the idle pair camp, they require every customers - including
those that followed the recommended practices in good faith - to dispose of all
of their existing hubs/switches/routers to make room for the users (or potential
users) who have cheated or sub-standard plants. This is a huge expense to place
on the backs of customers who have properly engineered plants just to allow a
minority the special advantage of not having to come up to spec".
I don't see it that way. Any scheme of idle pairs mid band insertion runs into
exactly the same problems as phantom power. Both schemes have to address the
compensation required to maintain Cat5 performance through the additional connectors
necessary to insert power.
I believe that phantom power is the better scheme because of its greater
universality. However, why can't we do both and let the market decide? Maximum
backward compatibility should be the goal. If we are careful in writing the
requirements for phantom mid span insertion then I see compenies making devices that
address both two pair UTP and the IBM Cabling System (ISC) as well as four pair 568.
To address the "lots", and "many". At the peak usage about 15% of the installed
cabling was the ICS. I would put the splitting of four pairs into two - two pairs
was a nit usually done by large universities. While these are large users there are
not many who did it.
I hope this is useful and not over kill.
Sorry I will not be attending the interim meeting due to a conflict. Also, I had a
stroke end of March and am still taking easy.
Jack Andresen
Mike_S_McCormack@xxxxxxxxxxx wrote:
> There are conflicting opinions on where the priorities should be. I'll be glad
> to take up the challenge to distract you from your work and make you all wade
> through my opinions for a while.
>
> There are a number of customer who have previously purchased Ethernet
> hubs/switches/routers and deployed them in their facilities. I believe that
> approximately 100% of the installed base fall into this category of investors.
> (I suspect that the number of us who are using near death alpha prototype
> equipment at home is less than a percent - perhaps I'm wrong.)
>
> Some number of the above sub-group of Ethernet users have "cheaped out" and
> either run just two pairs or have decided to alter their plant and run two
> Ethernet links over the installed four pair. I would conjecture that the vast
> majority of the people/organizations that did either of these thing knew they
> were cutting corners. Some potential users may very well have installed other
> facilities that they are migrating to Ethernet. These organizations/people may
> have installed the facilities in good faith and may now find that they can not
> take full advantage of the breath of the Ethernet, they are already precluded
> from 1000BASE-T.
>
> Of the power schemes that have been proposed, only the idle pair proposals have
> addressed preserving the investment of all of the current 802.3 users by
> allowing mid-span power insertion. While the signal pair camp may claim they
> are preserving the wiring infrastructure of a proportion of the of the 802.3
> users ignored by the idle pair camp, they require every customers - including
> those that followed the recommended practices in good faith - to dispose of all
> of their existing hubs/switches/routers to make room for the users (or potential
> users) who have cheated or sub-standard plants. This is a huge expense to place
> on the backs of customers who have properly engineered plants just to allow a
> minority the special advantage of not having to come up to spec.
>
> I am of the opinion (and trust me this whole mail is just opinions) that the
> real markets for power over Ethernet are not yet discovered, and between now and
> then a huge number of Ethernet ports will ship. If we require customers to
> replace all their wiring closet equipment, the adoption rate of power will be in
> fractions of a percent of the total shipments forever. If we provide a means
> for users do not have to fork lift all their capital equipment, we will allow
> the power applications to be added incrementally and the market will develop.
>
> The 802.3 has effectively already told the two pair users they are at the end of
> the road. We did this with the 1000BASE-T standard. These users should not be
> expecting the 802.3 to provide them any new technology on their old plants, we
> have demonstrated this to them previously. Why would we turn around and now say
> we were just kidding about not supporting two pairs, should we also re-examine
> if we can run 1G on two pairs?
>
> I am willing to characterize the performance of powered systems over CAT3 / CAT5
> per 568. Are we really saying we want to characterize this as well as every
> form of STP/UTP that could "commandeered" for Ethernet as well as every form of
> 24/26 gauge telephone wire (with and without stubs and / or but slices) ....? I
> for one would like a chance at completing a spec.
>
> I would say the idle pair mentality is the most inclusive, it allows use of 100%
> of the existing users to upgrade and the signal pairs group is the most
> exclusive, allowing no users to upgrade (without a forklift.) Limiting the
> scope of study to properly engineered plants allow at least some users to enjoy
> the benefits of powered Ethernet while open ended standards will never complete.
>
> The distraction of my opinion storm is over, you may return to your real work.
>
> Mike