Re: IEEE 802.3 Requirements

[Roy Bynum <rabynum@xxxxxxxxxxx>]

Michael M. Salzman wrote:
> 
> Hi Bruce, Ed, et al,
> 
> My experience is that on average no installer tests fiber for any thing
> other than connectivity.  To imagine that these fellows will carefully
> follow some timeconsuming and deliberate procedure to check out the cable is
> wishful thinking.  You are right that DMD is an innate 'feature' of most
> installed base fibers.  The ethernet community only recently discovered its
> ubiquity and impact.  Nevertheless we can expect the vast unwashed masses to
> blithely ignore any special handling and testing requirements untill their
> installation fails to come up and then they will search for causes.
> 
> In the case of 10 Gig, due to its novelty and likely expense, I think we can
> lay down new standards for fiber to support it, and customers would go along
> with the concept.  For those stubborn souls who insist on deploying the
> technology on existing fiber, I think the 10GEA can develop recommended test
> procedures and recommended equipment sets, and perhaps work with BICSI to
> develop a "gigabit technician" certification program.   If we do not address
> this prosaic aspect of our industry we are doomed to seeing more trial and
> error installations.
> 
> Mike.
> 
> > -----Original Message-----
> > From: owner-stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> >  Behalf Of Chang,
> > Edward S
> > Sent: Monday, May 17, 1999 06:36
> > To: Bruce_Tolley@xxxxxxxx; Chang, Edward S
> > Cc: Thomas Dineen; stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> > Subject: RE: IEEE 802.3 Requirements
> >
> >
> >
> > Bruce:
> >
> > The 62.5 um fibers have been used for over 15 or 20 years.
> > However, we just
> > started paying attention to the DMD fibers two years ago.  Because of the
> > small DMD population, industry did not paying attention to it.
> > In fact, the
> > DMD fibers have been with us since the graded index fibers were
> > introduced.
> > DMD fibers are defected parts like any other products having
> > defected parts.
> >
> > In the past, the MM fibers, particularly 62.5 fibers, were only used with
> > LED sources over-filing the fibers, which is hardly capable of creating a
> > DMD results except low bandwidth.  It was until GbE requiring laser over
> > 62.5 um fiber, the DMD has not been identified as a detrimental
> > problem.
> >
> > The fiber vendors do not characterize "DMD" as one of the parameters in
> > their commercial specification due to its very small, negligible
> > population.
> > As a result, no one really pays attention to verify it, unless an
> > experienced engineer is purposely looking for DMD fibers.  Some time, just
> > to identify DMD fibers from the waveforms is not a simple job.
> >
> > Ed Chang
> > Unisys Corporation
> > Edward.Chang@xxxxxxxxxx
> >
> >
> > ----Original Message-----
> > From: Bruce_Tolley@xxxxxxxx [mailto:Bruce_Tolley@xxxxxxxx]
> > Sent: Friday, May 14, 1999 5:29 PM
> > To: Chang, Edward S
> > Cc: Thomas Dineen; stds-802-3-hssg@xxxxxxxxxxxxxxxxxx
> > Subject: RE: IEEE 802.3 Requirements
> >
> >
> >
> >
> >
> > Ed:
> > As far as I know, hardly any "DMD fibers" have been identified to date.
> >
> > Bruce
> >
> >
Mike,

There are handheld test units for single mode fiber that will determine
the attenuation of the fiber.  I would imagine that such things exist
for MMF as well.  Professional installation people should already have
them.

I think that specifying minimum operational fiber requirements for MMF
and SMF with 10GbE is a good idea.  I have had to trouble shoot fiber
and cable plant before.  Without a minimum specification it is sometimes
difficult to justify, with management, upgrading to the proper physical
meda.  A standard will help those people who have to install and support
10GbE.

					Thank you,
					Roy Bynum