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RE: PMD discussion


802.3z not only supported the installed base of 62.5 um fiber (which has two
bandwidth grades), but also included 50 um fiber in two grades. These are a
400 MHz-km grade (representing the worst installed base grade of 50 um) and
a newer 500 MHz-km grade that allowed the SX solution to meet the 550 m
distance objective. I don't think customers have had a difficult time
getting GbE technologies to work in this situation. But we are sensitive to
this issue. So recognizing the need to distinguish new MMF from old, Lucent
has made the new fiber easily identifiable. New MMF cable and patch panels
are distinctly color coded to distinguish them from other fiber types. 

I cannot predict the percentage of new versus old fiber, since I don't have
a crystal ball. But I believe it will be a significant amount with
conversion accelerating as other fiber suppliers come on line. Lucent
already shipped hundreds of kilometers of new MMF and we are still ramping
up production. Also, I believe that deployment will tend to occur most
rapidly in those customer sites that intend to use 10GbE equipment in the
near term. So the absolute percentage conversion is not the key indicator to
monitor, but rather the conversion occurring in 10GbE customers sites.

When I look at the 10 port types, I see them serving several types of
customers. I believe that it will be a rare customer that must make a choice
between all 10 types. The norm is likely a choice between a small subset
that is targeted for their needs. While most of the choices will not apply
for any one customer, all of the choices have their purpose in serving the
entire customer base. Let's not loose site of the fact that 802.3 is
entering new market spaces. These new spaces are embodied in the 10 and 40
km distance objectives that far exceed the scope of building cabling (the
scope of Ethernet up to now), and PHY objectives which address both LAN and
WAN. Larger and more diverse market spaces will naturally need a greater
variety of solutions. 

Paul Kolesar

	From:  Booth, Bradley [SMTP:bradley.booth@xxxxxxxxx]
	Sent:  Thursday, June 01, 2000 3:36 PM
	To:  '802.3ae'
	Subject:  RE: PMD discussion


	We did "fixate" on the installed fiber for 802.3z.  I think that was
part of
	the success of 1000BASE-SX.  As you and I both know, that by the
time the
	standard is complete, the new MMF will be part of the installed
base.  What
	is going to be the percentage of new versus old?  Who is going to
have to
	handle the customer calls to determine if the customer is using the
	"correct" MMF for the job?  Not you, not I, but rather my customer.
I just
	want to ensure that we don't create a bigger mess (which equates to
	marketability) for them.

	I look at what has made Ethernet so popular in the past, and that
has been
	its simplicity for the users.  Five PMDs with 10 port types is not


			-----Original Message-----
			From:	Kolesar, Paul F (Paul)
			Sent:	Thursday, June 01, 2000 11:32 AM
			To:	'802.3ae'
			Subject:	RE: PMD discussion

			Your customer's view is understandable considering
	present installed
			fiber situation. But don't make the mistake of
fixating only
	on the existing
			cable, as was done by supporters of 100BASE-T4 and
			infrastructure composition is dynamic and is ever
	to more capable
			and refined products, just like equipment end points
	By the time the
			standard is complete new MMF will be an installed
	fiber. The 802.3
			experience with 100BASE-T should be our guide. The
fact that
	3 copper PMDs
			existed neither retarded the market or caused
	complications for
			equipment providers. And new Cat 5 UTP became the
	base in less
			than two years, going into horizontals which are
much more
	difficult to
			upgrade than building backbones and equipment rooms.

			Paul Kolesar