RE: PMD discussion
Brad,
There are no PMDs in the set of 5 that do not meet at least one of the
objectives. As far as the 850 nm serial PMD, I believe I made a strong case
at the May interim as to why it also broadly meets the criteria. 80% of the
market for 10GbE will be under 300 m. A solution optimized for this large a
portion of the market has broad market application regardless of the number
of distance objectives it covers.
To your point on a small subset getting 100% majority, the indication of the
straw poll from the May interim is that down selecting below 5 PMDs this is
going in the wrong direction to achieve consensus. The poll indicated that
the 5 PMD set was favored by roughly 2 to 1 compared to the closest
alternative of 3 PMDs. Further, I believe that the 3 PMDs are not the same 3
among the supporters of that choice, which subdivides the support. From my
perspective an inclusive approach will work better than an exclusive
approach in getting to consensus. In an inclusive approach you get the PMDs
you prefer, while others also get the PMDs they prefer. If you really
believe the market will be best served by some subset of the PMDs, you are
free to use only those.
Regards,
Paul Kolesar
----------
From: Booth, Bradley [SMTP:bradley.booth@xxxxxxxxx]
Sent: Thursday, June 01, 2000 5:19 PM
To: '802.3ae'
Subject: RE: PMD discussion
Paul,
You touched on a key point. To quote you, "The norm is likely a
choice
between a small subset that is targeted for their needs." I see
this as
applying directly to what we need to work on. If there is something
available from another standards body (i.e. VSR VCSELs), then I
would prefer
to leave that effort in that standards body especially if it doesn't
broadly
satisfy our criteria. I think there is a small subset that the IEEE
needs
to standardize that we (I'm talking 100% majority) believe we should
focus
our effort on to meet our objectives while providing a small subset
to
satisfy our customer's needs.
Cheers,
Brad
-----Original Message-----
From: Kolesar, Paul F (Paul)
[mailto:pkolesar@xxxxxxxxxx]
Sent: Thursday, June 01, 2000 4:06 PM
To: '802.3ae'; 'Booth, Bradley'
Subject: RE: PMD discussion
Brad,
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.
Regards,
Paul Kolesar