On Sun, March 11, 2012 12:41 pm, Spehro Pefhany wrote:
> At 12:54 PM 3/11/2012, you wrote:
>
>>Using integrated magnetics saves a *huge* amount of time and vastly
>>improves your chances of design success.
>>
>>Matt Bennett
>>Just outside of Austin, TX
>>30.51,-97.91
>
> Interesting. Every Ethernet switch that I've opened up has used
> non-integrated magnetics, including the whack of Trendnet 8-port
> gigabit switches that I upgraded to a year or so ago**.

I wouldn't call any Trendnet product high-end... :) At the level of the
stuff I buy at Fry's for my home (I have plenty of Trendnet stuff here)- a
standard non-managed switch is a commodity- price and operation are a
difficult trade-off, usually leaning towards price.  The IEEE standards
are not enforced- they are voluntary guidelines, but they give people
something to fall back on, and a direction to point the blame when things
fail.

A consumer setup tends to be a lot more tolerant of errors- TCP/IP will
hide a lot of issues until they become particularly egregious.  In a
server setup, where they are trying to get as much out of their network
equipment as they can, failures become more obvious, and the customers
will use that as leverage to push costs down in the next generation.

> I would have guessed that for a notebook, integrated magnetics
> would be a no-brainer, and that the Ethernet layout would be
> far from the most difficult part of the motherboard layout-
> the high speed stuff between memory and processor etc. would
> be where the challenge would be.

Inside your own box, you have much more control- but when you have to
connect to something outside of your own control, the specs are the only
thing to fall back on. Build it to the spec, and it will work, as long as
the spec isn't broken. If you have 100% control of the environment, there
are plenty of special tricks that you can use (for example, adjusting
drive levels, pre-emphasis).



Matt Bennett
Just outside of Austin, TX
30.51,-97.91

The views I express are my own, not that of my employer, a large
multinational corporation that you are familiar with.
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