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PMD by cable vintage




Vipul,
Contrary to my previous statement about the lack of data on percentages of
cables by vintage, I believe there is some information that can be extracted
by combining the information from two plots. Looking at the cable vintage
data and the cumulative distribution data for all cables, I believe it is
possible to say that in this data set approximately 50% of the cables are
pre-1991. I arrived at this result by weighting the vintage data so that it
equates to the cumulative data.

Paul

	----------
	From:  Kolesar, Paul F (Paul)
	Sent:  Tuesday, October 24, 2000 10:21 AM
	To:  Equalization Ad-Hoc Reflector; 'Vipul Bhatt'
	Subject:  RE: PMD data available


	Vipul,
	It is not possible to tell exactly where 99.99 percentile is due to
	resolution of the plot. But it is at 99% around 3.6 ps/km^1/2. The
plot
	flattens out at 100% above 4.6. So my best guess is 4.6. However, as
Henning
	Bulow (in a subsequent email) and I both point out, this data set
does not
	reflect the current statistics since much more low-PMD grade fiber
has been
	installed since 1997. Unfortunately, the paper provides no
information on
	the percentages of fiber of any vintage.  
	Regards,
	Paul
		----------
		From:  Vipul Bhatt [SMTP:vipul.bhatt@xxxxxxxxxxx]
		Sent:  Tuesday, October 24, 2000 12:44 AM
		To:  Equalization Ad-Hoc Reflector
		Subject:  RE: PMD data available


		Paul,

		This is useful; thanks. A couple of questions, in
anticipation of
	what
		the P802.3ae members may ask in the November meeting.

		- In the cumulative distribution plots, what is the 99.99
percentile
		value of PMD - the value below which 99.99% of the
population is?
	It's
		probably hard to figure out from the figures, but take a
shot.
		- Does the paper say anything about what percentage of total
fiber
	is
		pre-1992?

		Regards,
		Vipul

		==========================

		> -----Original Message-----
		> From: owner-stds-802-3-hssg-equal@xxxxxxxx
		> [mailto:owner-stds-802-3-hssg-equal@xxxxxxxx]On Behalf Of
		> Kolesar, Paul
		> F (Paul)
		> Sent: Monday, October 23, 2000 12:29 PM
		> To: Equalization Ad-Hoc Reflector; 'Vipul Bhatt'
		> Subject: PMD data available
		>
		>
		>
		> A Bellcore paper by J. Peters, A. Dori, and F. Kapron from
		> NFOEC'97 entitled
		> "BELLCORE'S FIBER MEASUREMENT AUDIT OF EXISTING CABLE
PLANT
		> FOR USE WITH
		> HIGH BANDWIDTH SYSTEMS" provides some field data about the
PMD
		> characteristics.
		>
		> I found a number of points relevant to the IEEE, which I
		> will summarize here

		<snip>