Re: Proper way to install shielded ethernet
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Posted by Phil Schuman on August 13, 2006, 12:07 pm
Please log in for more thread options > "Phil Schuman" wrote:
> > it would be interesting to learn a bit about your environment
> > that prompted the STP.... EMI from radio, radar, microwave, etc ? >
pieces,
> A few nuggets of information. Just nuggets, not hearty, satisfying > since it's late and I was gonna sleep before I logged on... :-)
and
> > What propted the STP? Some speculation about the future, the present, > the past.
bit,
> > THE FUTURE > I consulted with several cabling guys whose opinion I value quite a > which led in turn to my own online research. I found just enough
take 10
> information about 10 gig to become convinced that it makes sense to > gig specs into consideration when evaluating the scope and breadth of
a
> recabling job. The speculation comes into play because the standard
isn't
> actually ratified yet, so it'll be jiggling for a while yet before it
firms
> up. BUT, some cabling companies already sell cable that meets some
version
> of the draft standard, and it's nearly always STP. Ampnetconnect has
a
> number of interesting white papers on the subject, but they agree that
STP
> clearly outperforms UTP in 10 gig testing. They may come up with good
ways
> to deal with the ANEXT in the electronics, but for now, it's looking
like
> STP has the advantage. If we can spend an extra 30-40% on the cabling
job
> now, and that gives us another whole generation of network speeds in
10
> years (or whenever it comes up), then we'll be very happy we spend the
extra
> amount upfront.
not
> > THE PRESENT > We've had some very odd application errors that have defied normal > troubleshooting techniques. It's not the OS on the workstations, it's > the software environment on the workstations, it's not a gazillion
other
> things that we've ruled out. The network is the one thing we haven't
been
> able to provide with a conclusive alibi. Over the past 11 years, any
number
> of people have poked around in our cieling for any number of reasons,
and
> who knows if they all observed structured cabling standards in their
poking?
> So my current cabling infrastructure is a great big question mark.
there) is
> > THE PAST > Work that was done as recently as 2.5 years ago (just before I got > suspect. Jacks were terminated with only 2 pair, for example. I
don't know
> anything about the work that was done in prior years, or, again, if
my
> structured cabling standards were followed (and 2.5 years ago, they > certainly should have been punching down all 4 pair, imho). So again, > current cabling is a big question mark. Since I don't know if there
ARE
> some freakish sources of EMI that are inducing network errors (chances
are,
> not...but when all other possibilities have been ruled out, whatever
no
> remains, however unlikely, must be considered), and since STP seems a > reasonable prediction for 10 gig applications, it seemed best to make > assumptions and play it extremely safe. You have no idea how irksome
these
> bizzare application behaviours have been.
his
> > Also, anecdotally, I spoke to another local admin who recently rebuilt > network from the ground up with new cabling and switches, in
preparation for
> a new VoIP phone system. Wouldn't you know it, the wierd behaviour
some of
> his apps had been exhibiting, and which also defied resolution,
suddenly
> disappeared. His switches had not been reporting errors, yet once
his
> everything was swapped out, his apps were suddenly rock-solid. Since > switches hadn't cried foul, he's assumed his network was clean and
didn't
> give it another thought, so he was very suprised (and pleased) to find
the
> issues resolved.
the
> > All this speculation led to a fuzzy-logic consensus that going STP on > rewire was worth a shot in the short run, and could likely pay off in
the
> long run.
> > BJ > this has been a great thread, as I've not seen STP since the old Token Ring days. With the concept of EMI and various types of "noise" on the line, I was wondering is there any kind of "instrument" that could show exactly what the line was encountering over a period of time ? Especially if the switch is not showing ANY type of errors like CRC, etc. ie - what could the line momentarily experience that would not show up as an error ? hmmm - the circuit overloaded so it looks like a continuous collision ? | ||||||||||
