RE: Signal vs. Idle debate (was: Here's a new idea)
Hi Norman,
I have a few issues with the direction you are taking the
discussion so far. Let me explain.
> If the market is growing very rapidly, then existing owners
> of (what will soon
> be) absurdly bulky and expensive switches will be small
> fraction of the total
> Ethernet market, and catering to those old switches with
> add-on boxes to
> supply power will be a niche market.
On the other hand, we are in the business of selling products
today to solve problems, not create them. There are plenty of
switches being sold today that support VoIP but don't supply
power because there is no standard for it. Are these boxes
"old, absurdly bulky or expensive"? I don't think so. Some of
them are highly integrated and very cost effective. I could
give you examples but I think you know I am right.
> Whether we choose the data pair or the
> spare pair should be conditioned more on 1) the total cost
> to the buyer of
> equipment designed with DTE power in mind, and
As a standards committee member, I would put "must support the
installed base of equipment without interference" as a higher
priority than cost. The cost of ripping out existing gear is
substantial. But what I have to say is less relevant than the
decision by the committee to require compatibility with 10/100T.
> 2) on the
> needs of 1G and
> faster links, than on the cost of existing installations.
Again, the committee has clearly expressed that 10/100T is a
higher priority than 1000T. Unlike 10/100T, the Gigabit stuff
today actually operates very robustly. Much of the 10/100T
installed base has been built with less-than-ideal performance
but customers want to use it. If you have a PC with an older 100T
NIC installed, do you want its performance to be impacted by the
addition of mid-span patch panels that are designed to inject
power on PDTEs? In the case of the "spare pairs" no impact would
exist. Sure, future 1000T products would have to deal with power
injection on their outside pairs, but 1000T is better equipped
to do so with echo cancellers, FEC, and DSP capabilities.
> (Note that this
> argument says that the woes of existing 4-wire installations
> is relatively
> unimportant.) In other words, I think that powering 1G is
> more important
> in the long term than cheaply adding on to 10M ports' capabilities.
Unfortunately, that is not the direction that the committee has
already committed to. Support for 1000T should not be demanded at
the expense of either reliable or inexpensive 10/100T operation.
> -- Norm
Best Regards,
Dan Dove
HP ProCurve Networks